General Advice

  • Do not exceed the appropriate application rate. Increasing the dosage may result in damage to your plants
  • Store in a dry, frost free place away from children, pets and foodstuff
  • Wash hands and exposed skin after use
  • Gloves are recommended when handling this product
  • Land where the product has been applied should not be used for grazing or cropping for feeding stuffs within the following periods:
  • (a) two months in the case of pigs, and (b) three weeks in the case of other farmed animals
  • Children and pets can continue to use treated areas immediately after application. Some dogs may attempt to eat the product. To avoid this we recommend mixing well with the soil.
  • Contents may settle in transit

Frequently Asked Questions

Q. Can my children & pets go into the treated area?

A. Yes, children and pets can return to the treated areas after application. However some dogs will attempt to eat the product. To avoid this mix well with the soil.

Q. Will animals be attracted to this product?

A. Animals may be attracted to this product. Land where product has been applied should not be used for grazing or cropping for feed stuffs within the following periods (a) 2 months for pigs and (b) 3 weeks for other farm animals.

Q. What should I do if I put on too much of the product?

A. Remove any visible granules and heavily water the area to dissolve and wash through excess product.

Q. Can I use this on my lawn?

A. We do not recommend using this product for lawns. Choose a fertiliser that has been specifically designed for lawn use such as Aftercut ultra green Plus or SafeLawn.

For any other questions or advice please contact our Technical Advice line on: 01480 443789 (Mon-Fri 9am- 5pm) or email [email protected]

Blood Fish and Bone Fertiliser

Blood Fish and Bone Fertiliser is a balanced organically based fertiliser in powder form. The nitrogen in Fish, Blood and Bone encourages strong growth and healthy rich green foliage, whilst the slow release of phosphate promotes vigorous root growth. The added potash promotes flower colour and improves ripening of fruit and vegetables. Ideal for all round use – Shrubs, Vegetables, Root crops and Herbaceous plants.

Blood, Fish and Bone is a general purpose plant food for strong healthy growth. Blood, Fish and Bone fertiliser is a plant food provides a rapid boost to flowers, fruit and vegetables. Fish, Blood & Bone is an organic-based general purpose plant food which provides the major nutrients required for strong healthy growth. It is suitable for use on most types of flowers and ideal for feeding fruit and vegetables. Fish, Blood & Bone provides both a rapid boost and long-lasting results so a single application lasts up to six weeks to keep plants in best condition and encourage flowering.

How to use Blood Fish and Bone:
Before planting or sowing
1. Ensure that the area is free of weeds and that the soil is moist
2. Sprinkle granules evenly over the planting area at a rate of 70 g/m2 (2 oz/yd2)
3. Fork in well and water thoroughly if the soil is dry

Feeding established plants
1. Ensure the area is free of weeds and that the soil is moist
2. In spring and summer sprinkle granules evenly on to the soil around plants at a rate of 70 g/m2(2oz/yd2), avoiding contact with the plant itself
3. Water well after feeding
4. Repeat at intervals of up to 6 weeks for best results


  • Keep off plant leaves and stems
  • Do not exceed recommended application rate
  • Dogs may be attracted to the bonemeal in this product. Avoid use in areas where dogs have access or work the fertiliser into the soil after application and cover with a 5 cm (2”) layer of chipped bark, soil improver or similar material
  • Do not use in areas where cattle, sheep, goats and deer have access

We use Blood Meal as a fertilizer in two different applications: as a part of our primary all-purpose fertilizer mix and as a stand-alone nitrogen supplement. For most garden situations, the all-purpose mix is adequate, but we use the Blood Meal as an additional feed for Brassica crops (broccoli, cauliflower, kale, Brussels sprouts, cabbage), as a spring feeding for alliums (garlic and onions) and in soils that are seriously depleted of nitrogen.

Nitrogen is the plant macronutrient most likely to be depleted in your garden soil. Nitrogen comes from many sources, including the air, animal manure, compost and decaying plant residue. However, to be absorbed by your vegetable plants, Nitrogen must be converted into either ammonium (NH4+-N) or nitrate (NO3–N). The chemical form of Nitrogen is always shifting in your soil in a complex process known as the Nitrogen Cycle (read this article for more on the chemistry of soil Nitrogen), the important thing to know as an organic vegetable gardener is that Nitrogen in your soil is often lost due to leaching, denitrification and other natural processes. Therefore, to keep Nitrogen levels adequate in the garden, it is essential to add supplemental forms each season.

Nitrogen is the nutrient that is most responsible for the vegetative growth of a plant. This means that nitrogen is especially important for plants early in their development, as they develop the vegetative structure that will supply your harvest later on in the season.

Generally speaking, the larger and healthier your plant is, the more harvest it can produce. When planting fruiting crops such as tomatoes and peppers, it is essential to encourage lots of bushy growth on the plant before it starts to produce fruit. We’ve all seen the sad-looking bell pepper plant that is about 6 inches tall, has 4 leaves and puts on exactly one tiny pepper. This growth habit is an indication that the plant did not receive adequate nitrogen and has simply made due with the nutrients available. You can certainly commend the tenacity of this pepper, but as a gardener interested in voluminous harvests, it’d be better to encourage large, healthy plants that are able to produce many, many pepper fruits.

Blood meal is a pure source of nitrogen (13-0-0). It is a dry powder derived from cow’s blood which has been steamed or boiled to kill pathogens and remove impurities. It will supply crops with an immediate boost and continue to release useable N over the course of several weeks or months (depending on weather and soil conditions). We recommend using it as part of a balanced fertilizer blend and as a single ingredient application when appropriate. Rough guidelines are as follows:

  1. Apply ¼ Cup of blood meal to brassica plants at planting time

  2. Apply 1 Cup of blood meal per 5’ row of alliums in spring.

  3. Use a balanced fertilizer including blood meal when planting new vegetable crops each season. Application rates for fertilizers vary, follow the recommendations on the product label.

What Is Balanced Fertilizer – When To Use A Balanced Fertilizer

We all know that fertilizing now and again is an important part of keeping our plants healthy and increasing yields. However, purchased fertilizers come in many different formulas which are represented as an NPK ratio on the packaging. That is where balanced plant fertilizers come in. What is balanced fertilizer? These are indicated with the same numbers showing that equal amounts of macro-nutrients are present in the product. Knowing when to use a balanced fertilizer can help reduce any of the mystery behind these numbers.

What is Balanced Fertilizer?

Fertilizers are an essential part of gardening. You can fertilize with synthetic or natural products. Synthetic fertilizers are found in many different strengths and the amount of nutrients are indicated by the 3-number ratio on the product. Balanced fertilizer information is represented in identical numbers, such as 10-10-10.

The amounts of each macro-nutrient are identical in the formula which may sound like a perfect fit for all around plant feeding but actually may contain too much of one of the nutrients for individual plants. It is best to perform soil tests and know individual plant needs before using a balanced fertilizer.

The best way to demystify balanced plant fertilizers is to take a common formula and break it down into its nutrient amounts. So for a 10-10-10 balanced fertilizer in a 50-pound bag, you have 5 pounds or 10% of each macro-nutrient. These nutrients are nitrogen, phosphorus and potassium. These macro-nutrients are the essential building blocks of plant health.

Nitrogen drives foliar development while phosphorus develops vital root systems, fuels flower growth and eventually fruit production. Potassium is responsible for healthy cell development and plants that are strong enough to withstand any stress.

A balanced formula may not meet every plant’s needs and, in fact, can be detrimental to soil and plant health because it delivers too much of a nutrient. This is often the case with balanced fertilizers, as they contain more phosphorus than plants and soil require.

Additional Balanced Fertilizer Information

If you are confused as to what formula to purchase, try breaking down the ratio even further. For instance, the 10-10-10 is actually a 1-1-1 ratio where equal parts of each macro-nutrient are present.

If you are trying to get more fruit, the balanced fertilizer will not be the best method of feeding your plants. Instead, try a formula with a higher middle number to promote flowering and fruiting. A good example of this formula for growing tomatoes and other fruiting plants might be 5-10-5 or 10-20-10.

If you want green, leafy growth, such as that needed in growing lettuce crops, use a formula with a higher first number like a 10-5-5 distribution. At the end of the season, plants need to develop resistance to the cold temperatures that are coming and should not be growing new tender leaves. A formula with a higher last number will promote good root development and healthy cell structure.

When to Use a Balanced Fertilizer

If you are still trying to figure out what fertilizer is best for your landscape, a general purpose formula of 5-1-3 or 5-1-2 is usually sufficient for most plants. This is not a balanced fertilizer but is a complete fertilizer with some of each macro-nutrient present in the formula. The first number is higher to provide nitrogen to drive green growth.

If you use a balanced fertilizer, do so only once per year and make sure to provide plenty of water so any unused nutrients can be leached away from plant roots. This can result in a buildup of one or more of the nutrients in soil and can actually increase the amount of that nutrient in water tables if consistently used.

A better method is to skip the balanced fertilizer and use a formula that more directly targets your plant’s needs. This may mean that you need to keep around several fertilizers to accommodate fruiting plants, leafy vegetables, acid loving plants and other persnickety specimens.

Houseplant fertilizer basics: How and when to feed houseplants

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Being a houseplant parent can be confusing business! Unlike human babies, houseplants don’t cry when they’re hungry or uncomfortable. Instead, they respond to their environment in different, far more subtle, ways. Knowing when it’s time to feed houseplants is challenging stuff, even for long-time houseplant growers. Today, I’d like to review the basic ins and outs of houseplant fertilizer, and cue you in on how and when to feed your houseplants.

When to feed houseplants

Houseplants wilt when they need water. Their leaves grow pale and lanky when they aren’t getting enough sunlight. When the humidity is too low, they turn crispy; when it’s too high, they may develop rot. But, knowing when your houseplants need to be fertilized is far trickier. There’s no clear signal from your plant that shouts “Hey, it’s time to feed me!”, other than perhaps slowed or stagnant growth, which for many houseplant parents, is barely noticed. So, instead of waiting for a signal from the plant, you’ll have to take matters into your own hands and use houseplant fertilizer on a schedule that’s based on their growing cycle.

The timing of houseplant fertilizer applications should follow the seasons and their growth habits.

Each specific houseplant has slightly different needs when it comes to houseplant fertilizer amounts and frequency, but there’s no need to overly complicate the process. Yes, you could study up on each individual houseplant species you care for, determining its specific nutritional needs, but the truth is that the vast majority of common houseplants have fertilizer requirements that are similar enough that treating them in a singular way is more than enough to satisfy their nutritional needs. Some houseplants are heavier feeders than others, it’s true. But, a houseplant fertilizer schedule like the one found below, offers a good balance that both satisfies heavy feeders and keeps you from going overboard with those houseplants that require lower amounts of fertilizer.

Here’s the best fertilizer schedule for most common houseplants. It’s based on the cycle of the growing season, which, though they are inside where temperatures are more consistent, influences houseplants much the same way it influences outdoor plants.

Water-soluble liquid houseplant fertilizers are applied only during periods of active growth.

The best houseplant fertilizer schedule

In a bit, I’ll discuss different houseplant fertilizer products mentioned here and how to apply them, but here’s the low-down on when they should be used.

Spring houseplant fertilizer schedule:

  • Start fertilizing houseplants about 8 weeks before the last expected spring frost. For example, here in Pennsylvania, where I live, the danger of spring frost typically passes around May 15th. This means I begin to fertilize my houseplants in mid-March. This is when the days begin to lengthen noticeably and houseplants shift from a semi-dormant state into a period of active growth.
  • The first three fertilizer applications should be made at half the recommended strength. If it’s a granular product, use half the amount suggested on the label. If it’s a liquid houseplant fertilizer, mix it to half strength (more on these two types of fertilizers in a bit). This feeds houseplants at a time when they’re really just gearing up for active growth and they don’t yet require larger amounts of nutrients to fuel prolific growth.

Summer houseplant fertilization schedule:

  • When summer arrives, it’s time to switch to a more regular houseplant fertilizer program.
  • Base the frequency of summer fertilizer applications on the type of fertilizer you’re using.
  1. Liquid fertilizers are applied more frequently, bi-weekly or monthly, for example.
  2. Granular products are used less frequently, perhaps once every month or two.
  3. Slow-release houseplant fertilizers break down slowly and release their nutrients in small amounts, over a longer period of time. A single application of most of these products lasts for three to four months.

Liquid organic houseplant fertilizer is a great choice because it’s made from naturally derived ingredients.

  • Follow this schedule regardless of whether you move your houseplants outdoors for the summer or not. Houseplants are in a state of active growth when summer light levels are high, regardless of whether they’re exposed to the consistent temperatures of a home environment or the ups and downs of sitting out on a patio or terrace.

Fall houseplant fertilization schedule:

  • About 8 weeks before your first expected fall frost, taper off your houseplant fertilizer amounts and frequency. At my house, that means starting in mid-August, I reduce the amount of fertilizer by half and start extending the amount of time between fertilizing for about 3-4 applications, which typically takes me to about the time of winter’s arrival.

Winter houseplant fertilization schedule:

  • None. Houseplants are not in a state of active growth during the winter and therefore should not be fertilized. Doing so can lead to fertilizer burn and brown leaf tips (more on why this happens here).

Don’t fertilize houseplants, such as this large spotted Dieffenbachia, during the winter when they’re not in a period of active growth.

Two exceptions to these rules:

  1. If you live in a climate that does not receive regular winter frosts, continue to fertilize houseplants all winter long, but do it at half the strength and frequency of your summer applications. Again, this is due to light levels more than temperatures.
  2. And, if you live in a tropical climate, where it’s warm all the time, keep your houseplants on a summer fertilization schedule year-round.

What’s in houseplant fertilizer?

Most houseplant fertilizers contain a mixture of both macro- and micronutrients. The three primary macronutrients, nitrogen, phosphorous, and potassium, found in a container of fertilizer are listed as a ratio on the front of the bottle or bag. Called the N-P-K ratio, these numbers tell you the percentage of each of those nutrients inside the container. The ratio of these macronutrients in a tomato fertilizer or a lawn fertilizer is different than the ratio found in a houseplant fertilizer as each of these groups of plants has different nutritional needs. This means using a fertilizer formulated specifically for houseplants is a must. That should be the first thing you look for when purchasing houseplant fertilizer. It should say “for houseplants” somewhere on the packaging.

The ratio of N-P-K is on the label of every houseplant fertilizer. This one is higher in P, making it good for blooming plants like African violets.

Phosphorous (the middle number on the container) is essential for flowering. Houseplant fertilizers for flowering plants should have a slightly higher amount of phosphorous in them (1-3-1, for example). Those used on green houseplants that don’t typically produce flowers, should be slightly higher in nitrogen. They may also contain a balanced ratio of nutrients (5-3-3 or 5-5-5, for example). I typically use one houseplant fertilizer for my flowering houseplants and a separate one for non-flowering types. This isn’t necessary unless you’re growing flowering houseplants like African violets, begonias, or gloxinia.

Many, but not all, fertilizers also contain secondary macronutrients, like calcium and magnesium, as well as micronutrients, such as iron, zinc, and boron. These nutrients are used in smaller amounts than the primary macronutrients of N, P, and K, but they are still essential to every plant’s metabolic pathway. You’ll want to be sure your houseplant fertilizer contains a small amount of these nutrients as well.

Houseplants won’t tell you when they need to be fertilized, so you’ll need to put them on a schedule.

Ingredients in houseplant fertilizers

The ideal houseplant fertilizer is made from naturally derived sources of these macro- and micronutrients, not made from chemicals synthesized in a laboratory. Though those blue, water-soluble fertilizers are commonly recommended, they aren’t the most eco-friendly source of nutrition for your plants, nor do they contain any micronutrients. Instead, turn to either a liquid or granular houseplant fertilizer made from natural ingredients to feed your houseplant babies.

Organic plant fertilizers are made from plant-, animal-, and mineral-based components.

Types of houseplant fertilizer

Now that you know when to fertilize houseplants and what nutrients houseplant fertilizers should contain, it’s time to look at the different types of houseplant fertilizer to determine which one is right for you.

Liquid houseplant fertilizer

They need to be used a bit more frequently than granular fertilizer, but organic liquid houseplant fertilizers are my personal favorites. Brands like Grow!, Espoma’s Indoor Houseplants, Liquid Love, and Jobes Water-soluable All-Purpose Fertilizer contain ingredients derived from plants and animals, as well as from mined minerals. Liquid fertilizers also come with a reduced risk of fertilizer burn. Another benefit of using liquid fertilizers made from naturally-occurring ingredients is that in addition to providing a houseplant with nutrients, they also act as growth enhancers. They are full of dozens of micronutrients, trace elements, vitamins, amino acids, and plant hormones, each of which plays a vital role in the health and vigor of your houseplants.

Organic liquid houseplant fertilizers are made from liquid kelp, fish emulsion, compost tea, worm tea, liquid bone meal, rock phosphate, plant extracts, and humic acids, to name just a few.

Liquid and water-soluble houseplant fertilizers are mixed with irrigation water and applied to plants.

Granular houseplant fertilizer

Granular fertilizers for houseplants are found in one of two formulations: as loose, granular pellets or as compressed fertilizer “spikes.” Pelletized granular fertilizers for houseplants, such as Organic Plant Magic and Be-1, are sprinkled on the surface of the soil. Compressed fertilizer “spikes,” such as Jobes Organic and EarthPods, are pushed down into the soil to come in close contact with plant roots.

The best pelletized and compressed granular houseplant fertilizers are made from naturally derived ingredients. These include dehydrated worm castings, bone meal, blood meal, sulfate of potash, limestone, rock phosphate, and other animal-, mineral-, and plant-based ingredients. Synthetic chemical-based granular fertilizers are available for houseplants, too, though I avoid them. A quick check of the ingredient list on the label tells you what the fertilizer is made from. If you don’t see any ingredient list at all, it’s a synthetic fertilizer.

Houseplant fertilizer spikes are easy to insert into the soil.

Slow-release houseplant fertilizers

Also called time-released fertilizers , slow-release houseplant fertilizers are made from a synthetic source of nutrients. The liquid nutrients are encapsulated in a coating. This coating breaks down slowly and releases the nutrients in low doses over a long period of time. Products like these mean you’ll be fertilizing less frequently. It’s very convenient, but do be aware that they aren’t made from eco-friendly ingredients.

The coating on slow-release fertilizers mean the nutrients are available to plants for a long period of time. However, they are chemically derived.

Houseplant fertilizer in a nutshell

As you can see, fertilizing houseplants doesn’t have to be an overly complex practice. Use the right products and apply them according to a seasonal schedule, and your houseplant family will be as happy and healthy as can be.

For more on houseplants, check out the following articles:
Apartment Plants: The best houseplants for apartment living
Air Plant Care: How to tend, water, and fertilize Tillandsia
Tips for repotting a Phalaenopsis orchid
Easy projects for mini holiday houseplants

How do you feed your houseplants? We’d love to hear about it in the comment section below.

Summary: A complete fertilizer or plant food – organic or inorganic – is one very key “item” for success in the lawn, with landscape plants, in your garden, and with your houseplants. With a little study of fertilizers and their recommended uses, you can save money and increase productivity.

Question: The garden center recommended a “complete fertilizer” to use on the lawn, landscape trees and shrubs for my yard, how do I go about choosing the right fertilizer for my use? Martin, Peachtree, Georgia

Answer: Martin, homeowners face many options in choosing from a great variety of foods for their fertilizer applications on the market today, and may at times be uncertain which one to select for their particular needs.

It’s always best to get a soil test before applying and type of “plant food” the lawn, or garden.

There are organic and inorganic fertilizers, both of which are available in powdered, liquid and granular fertilizer forms.

Then, some are complete, or balanced fertilizers; others are prepared for special purposes like a starter fertilizer.

A study of fertilizers and their recommended uses is well worthwhile, both in terms of money saved and in increased productivity.

What Are The Essential Elements of Complete Fertilizer?

All complete fertilizers must contain three basic elements:

  • (1) Nitrogen, which promotes leaf and stem growth
  • (2) Phosphorus, which helps plants grow and flower as well as makes their stems strong
  • (3) Potash, (potassium) which aids root growth and, to a certain extent, acts as a balance wheel between the other two.

By law, the percentage of these three fertilizer elements making up the “plant food” must be printed on the bag or container.

The percentage, or the number of pounds of each fertilizer element per 100 pounds, is expressed in numbers such as:

  • 10-5-5
  • 5-10-10
  • 5-8-7
  • 20-20-20

… and so forth, and always in the same order: nitrogen, phosphorus, potash also known as n-p-k ratio.

For example, a low nitrogen fertilizer 5-10-10 is such because the 1st number represents nitrogen.

If the total amount of each element in a particular fertilizer is not in a form which plants can use as plant food, the analysis must also show the percentage which is available to plants.

Many fertilizers also contain some:

  • Iron
  • Copper
  • Manganese
  • Calcium

… etc., which may or may not be listed. The bag also lists the recommended amount of fertilizer material to apply per square foot.

What Are The Basic Types Of Plant Food Fertilizer?

There are several ways to classify fertilizers, but first we shall divide them according to whether they are organic or inorganic.

Complete organic fertilizers are those derived from animals or from plants.

Bone meal comes from ground bones of animals and other waste materials from the slaughterhouse.

Widely used as an organic fertilizer due to its high phosphorus and protein content.

Blood meal or dried blood serves as one of the highest nitrogen sources. It also provides high protein content.

This comes as a dry, inert powder made up of cattle or pigs blood from the abattoir.

Fish emulsion fertilizer or fishmeal, this organic fertilizer develops from bones, left-over offals, and wild-caught, small marine fish.

This fertilizer delivers more protein than any other plant nutrients.

According to EPA in the US, treated and recycled sewage sludges (milorganite) for sustaining and improving productive soils. Also, it distributes enough plant nutrients that support plant growth.

Cottonseed meal comes as a by-product of cotton and works as a slow-release fertilizer which everyone sees as a high-quality nutrient recommended for great plant growth.

This slow-release fertilizer improves soil texture, aids in the production of humus, and protects the soil from rapid erosion.

On the other hand, kelp meal or seaweed fertilizer serves as another good organic amendment to the soil. It wakes up microbes in the soil to help break down organic matter for plants to consume.

Manure (fresh or dried), derived from animal feces is a common organic fertilizer used by farmers to cultivate the soil.

High in organic matter and nutrients, this material greatly contributes to the fertility of the soil and a bounty harvest. You find manure often mixed with compost.

These materials are comparatively low in their chemical analysis but they often appear to furnish benefits out of proportion to their content.

They cannot burn your plants and they release their chemicals slowly as they gradually decay.

Natural Chemicals In Fertilizer

The inorganic fertilizers are already in their basic chemical form. A number of them, like some limes and rock phosphates, are natural chemicals.

Others are manufactured chemicals. Since they are already in chemical form—which is the only way in which the plants can absorb them regardless of their origin – they take effect much faster than organic fertilizers. Decay is not necessary.

Other points in their favor are that they are usually cheaper, you can control more accurately the amount of plant foods you provide.

They also have higher concentrations of plant fertilizers so that you need less inorganic than organic fertilizer to do the same job.

What Is Synthetic Fertilizer? = Man-Made Chemicals

To confuse us, however, science has now given us synthetic organics, man-made “natural foods.”

These fertilizers are members of the urea-form group, relatives of the plastics, and release their one plant food, nitrogen, slowly as they decay.

In the North they may release it over the entire growing season; in the South they break down more quickly.

Although they are highly concentrated – containing up to 40 percent, or more – they cannot burn roots or leaves. Nitroform has been a widely advertised brand.

Liquid Fertilizers

A third basic group is the water-soluble liquid plant fertilizers.

Here we include both types the organic liquid fertilizers such as the liquid fish emulsions and the purely chemical, or inorganic, water-soluble fertilizer powders and liquids.

Both are convenient to use and equally effective in the soil. The inorganic group, however, lends itself to somewhat more rapid absorption when used for foliar or on-the-leaf feeding.

They usually come in more highly concentrated form and a little goes a long way. But, by the same token, they must be used with greater care and strict adherence to the manufacturer’s instructions.

Read More On: How To Use Plant Fertilizer Concentrates

Specialized Fertilizer

Finally, we have specialized fertilizer such as lime-free Azalea bush food, Camellia, and holly fertilizers, natural rose fertilizers, bulb foods, and African-violet fertilizers etc.

Their uses are indicated by their names. In this category, too, are the common gypsum, used in limestone sections to supply calcium without increasing alkalinity, and sulfur, used as a minor plant food and soil acidifier.

Fertilizer By Content Type

We can also divide fertilizers into two groups according to their contents.

One is the high-nitrogen fertilizer type, which promotes leafy growth on lawns, leaf vegetables, and foliage plants – this is why you should Know the Fertilizer numbers.

A good example of this is 10-5-5, used as a grass fertilizer in some areas. The other is the low-nitrogen type, in which phosphorus and potash play a more important part.

One of these is 5-10-10, used primarily as a tree, rose, and bulb food. Use the first type where stem and leaf growth is wanted and the second where flowers and fruits are important, as well as for all root crops.

Read More On: Applying Fertilizer… How Much

Hopefully you now have a better idea of the fertilizer you need for the job and can now buy the “complete fertilizer” needed to do the job.

Slow release fertilizer VS. Controlled release fertilizer

Both slow release fertilizers (SRF) and controlled release fertilizers (CRF) supply nutrients gradually. Yet, slow release fertilizers and controlled release fertilizers differ in many ways: The technology they use, the release mechanism, longevity, release controlling factors and more.

Follow the table below to learn about the main differences, by comparing Haifa’s Multicote™ technology with the three main technologies used by slow release fertilizers:

Multicote™ SCU, Poly-SCU IBDU Methylene Urea, Ureaform
Technology Polymer coating Sulfur-based coating Urea reaction product Urea reaction product
Release mechanism Diffusion Rapture of coating Hydrolysis Microbial degradation
Longevity 2-16 months, depends on the coating thickness 2-2.5 months Depends on particle size MU: 12 weeks
UF: 12 months
Release controlling factors Temperature Microbial activity, moisture, temperature Soil moisture, temperature Microbial activity, moisture, temperature, pH, organic matter
Controlled-release N (% of total N)* 100% 40-50% 85% MU: 50%
UF: 20%
Additional nutrients in a controlled-release form Controlled-release NPK formulae

Slow release fertilizer: less control over nutrient release

As shown in the table, only one factor – soil temperature – affects the nutrients release of controlled release fertilizers. As for slow release fertilizers, there are multiple factors affecting the release (soil moisture, temperate, pH, etc.). Thus, using controlled release fertilizers the nutrient release is much more predictable.

Haifa’s controlled release fertilizers

Haifa’s controlled release fertilizers offer continuous release of nutrients throughout the growth season, optimized nutrition in a single easy application, reduced application rates and many other benefits.

Controlled release fertilizers – how does it work? watch the video:

Learn more about our Multicote™ products

An introduction to Controlled Release Fertilizers

Coated or controlled release fertilizers (CRF) have become increasingly popular and have gathered a great deal of attention from growers and agronomists around the world.

Applying lower amounts of fertilizer is one solution to dealing with new regulations limiting the amount of leached nitrogen. Scientific proof has shown that growers can achieve the goal of higher production and higher quality with coated fertilizers. These fertilizers achieve results which are at least as good as standard fertilization while using less fertilizer, sometimes up to 25% less, with the benefit of leaching fewer nutrients, and requiring fewer application passes.

CRFs are used in all agricultural and horticultural crops all over the world. Each application in a particular climate calls for a specific fertilization strategy. Due to the differing length of time that each CRF granule takes to release the nutrients inside, it is possible to fertilize on cycles as short as six weeks and as long as eighteen months.

CRF’s are fertilizers with one or more primary macro-, meso- or micro-nutrients in a coated granule. There are different types of coating which gradually release the nutrients. Blends are often produced in order to achieve the correct nutrient levels for every crop. There is a wide range of available product; from 100% coated NPK with trace elements to partially coated blends (N and/or P and/or K) with or without trace elements.

These are all CRF products! However, the most important part of a CRF is the coating itself. The difference in coating percentages affects the direct availability of nutrients to the plant as well as the leaching during the growth season. The type of coating is also important, whether it’s a resin coating, a sulphate coating with a higher initial release, or a coating of polymer (polyethylene). Each coating technology has its own specific characteristics. Factors influencing the release of nutrients are moisture content and soil temperature. In resin or sulphate coatings, the release mechanism is primarily determined by the thickness of the coating. There are also coated products available in which the microbiology within the soil affects the release pattern.

During the production process, the choice of nutrients combined with the type of coating are the key factors in the release of macro- and micro-nutrients. If this combination is not correct, not all of the macro-nutrients (or especially the micro- elements) will be released. If the nutrients remain in the granule, they cannot benefit the plant.

What are the advantages of CRFs?

For the best results, choose a CRF to meet the needs of a particular crop, taking into account soil type, temperature and cultivation method. Also consider how the individual elements are released as well as the CRF’s period of effectiveness. For example, autumn leeks have a different requirement to winter leeks.

CRFs have many advantages:

  • Better plant growth due to the continuous and uniform availability of the nutrients.
  • It is possible to reduce fertilizer application by 20-25% as the risk of leaching is minimal. Of course, even with a CRF, rain will wash away the minerals which are present in the root environment, but the CRF will immediately release new nutrients.
  • The positive effects of CRF application include higher yields, better quality distribution, more uniform grading, a higher tuber, and greater plant weight. Because the plant grows evenly and gradually, it is less susceptible to damage and diseases such as aphids or powdery mildew and will show less deficiencies.

How do you select the right CRF?
It can be hard for growers to differentiate between the various CRFs and choose the one that is right for their crop needs, climate needs and, of course, their budget. Perhaps the most important aspect is the efficiency:
Does the release of nutrients meet the needs of the plant during the whole growth stage?
Suppliers of CRF will be able to advise you on specific fertilization questions and in consultation with the producer (ICL SF, for instance), it is possible for growers to receive custom advice without obligation. It is even possible to draw up a nutrient release chart over time, per nutrient, taking all the relevant conditions into account.
ICL SF has a very broad portfolio of CRF products; e.g. Agroblen, Agromaster and Agrocote. These products have different types of coating, differing coating percentages and different longevities and can thus suit a wide range of crops.

Our production methods are verified by three different ISO certifications and all products are REACH compliant.

By ICL Specialty Fertilizers
Agronomist team

Controlled-Release Fertilizer

Do you want to benefit from state-of-the-art technology and offer farmers a broad smart fertilizer product range, fine-tuned to specific customer and crop needs? Our Controlled-Release Fertilizer Design with PurActive Technology, developed in partnership with Pursell Agri-Tech, offers you a one-stop-shop package to kick-start your new product line.

Our modular design is easy to implement and allows you to produce under your own brand name and colour. The PurActive technology trademark serves as a warranty for farmers, guaranteeing them the best product available.

A smart fertilizer

In order to feed the growing world population, more efficient and sustainable fertilizers are needed. Our Controlled-Release Fertilizer Design with PurActive Technology provides the required nutrients at the right time and the right rate, resulting in a more efficient use of nutrients. This smart innovation helps farmers improve their yields and optimize their production.

How it works

The smart fertilizer has a polymer coating that contains the nutrients inside the membrane. It prevents valuable nutrients from leaching into the soil and volatilizing into the air. The coating provides a semi-permeable membrane around the fertilizer. Due to the fertilizer’s hygroscopic nature, water will permeate through the membrane, allowing the nutrients to dissolve. The low nutrient concentration outside the membrane, will act as a driving force to permeate dissolved nutrients through the membrane into the soil. This process is mainly controlled by temperature and thus synchronized with the growing process of the plant, leading to an extremely effective nutrient uptake.

High Phosphorus Plant Food

Phosphorus is included in most plant foods and fertilizers because it helps develop plant roots and improve bloom production and size. Plant foods with high phosphorus content can help when soil has plenty of the other major nutrients but lacks phosphorus, or when a plant has especially high phosphorus needs.


Plants need high amounts of phosphorus because it is essential to building their genetic material and helps plants store and transport nutrients quickly. When nutrition transport happens rapidly, the plant is free to produce ample blooms, push roots further into the ground faster, and develop quickly overall. This is one of the reasons that high-phosphorus plant foods and fertilizers are often labeled “bloom-boosters.”


On a plant food or fertilizer label, there are three numbers separated by dashes. Phosphorus is the middle number. Therefore, if the middle number is higher than the other two numbers, then it is a high-phosphorus plant food. High-phosphorus plant foods come in liquid or granular form. The form does not affect how well the plant food is absorbed, so long as it is applied correctly. Granular fertilizers and bone meal are best mixed into the planting medium before planting, while liquid fertilizers should be applied after the plant is established. Guano and rock phosphate are other organic phosphorus sources, but guano sometimes has a higher nitrogen content.


Annual flowers and annual fruit, seed, and root crops benefit most from high phosphorus plant foods, since they have only a year to absorb, transport and use nutrients before the end of their lives. Perennial flowering plants and crops that are valued for their blooms or fruits benefit from an application of high-phosphorus plant foods, but take care when re-applying. Phosphorus does not leach through the soil the way that nitrogen does, so test the soil before reapplying.


Repeat applications of phosphorus, whether organic or chemical, can harm your plants. Too much phosphorus in the soil locks up zinc and iron, which plants need to survive. It can take several years for phosphorus to stabilize in the soil so that it no longer inhibits zinc and iron. Excess phosphorus on the surface of soil can also wash down into nearby clear water, where it encourages the growth of weeds and algae. Test your soil every two to three years to make sure you are not overfertilizing your garden.


Using balanced plant food or switching to well-rotted manures and compost provides plants not only their phosphorus needs, but also nitrogen, phosphorus, trace nutrients, good soil structure and high beneficial microbe activity. To help your plants develop healthy roots and plentiful blooms, plant them in rich, well-drained soil in a sunny location. Rotate crops and annual flowerbeds with plants that do not require as much phosphorus so you will not need to apply high phosphorus plant foods as often.

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Fertilizer 101: The Big 3 – Nitrogen, Phosphorus and Potassium

It’s the earth’s cultivated cropland that keeps humanity alive and thriving. Plants provide food, fiber, housing and a host of other benefits, and fertilizer plays a key role in this process. As the world population is expected to exceed 9 billion by 2050, fertilizer will be needed more than ever to boost crop production to keep people fed and healthy.

All growing plants need 17 essential elements to grow to their full genetic potential. Of these 17, 14 are absorbed by plants through the soil, while the remaining three come from air and water.

Generations of soil science have yielded knowledge of how to test nutrient levels in soil, how plants take them up and how best to replace those nutrients after harvest. That’s where fertilizer comes in.

Nitrogen, phosphorus and potassium, or NPK, are the “Big 3” primary nutrients in commercial fertilizers. Each of these fundamental nutrients plays a key role in plant nutrition.

Nitrogen is considered to be the most important nutrient, and plants absorb more nitrogen than any other element. Nitrogen is essential to in making sure plants are healthy as they develop and nutritious to eat after they’re harvested. That’s because nitrogen is essential in the formation of protein, and protein makes up much of the tissues of most living things. Below is a picture of corn that is nitrogen deficient.

The second of the Big 3, phosphorus, is linked to a plant’s ability to use and store energy, including the process of photosynthesis. It’s also needed to help plants grow and develop normally. Phosphorus in commercial fertilizers comes from phosphate rock. Below is a picture of corn that is phosphorus deficient.

Potassium is the third key nutrient of commercial fertilizers. It helps strengthen plants’ abilities to resist disease and plays an important role in increasing crop yields and overall quality. Potassium also protects the plant when the weather is cold or dry, strengthening its root system and preventing wilt. Below is a picture of corn that is potassium deficient.

The Big 3—nitrogen, phosphorus and potassium—provide the foundational nutrients of today’s commercial fertilizers. Keep following The Voice as we continue to explore fertilizer in-depth in the weeks ahead.

For more information on the the “Big 3” nutrients in commercial fertilizers, check out the 4R Educational Modules on nitrogen, phosphorus and potassium.

Fertilizing Flower Gardens and Avoid Too Much Phosphorus

Most home garden fertilizers are complete fertilizers, which contain the macronutrients required by plants in the largest amounts. The numbers on a fertilizer bag refer to the percentage of nitrogen (N), phosphorus (P2O5) and potassium (K2O) (in this order).

Complete fertilizers sold as “all-purpose” fertilizers for gardens, such as 24-8-16 or 12-4-8 often contain higher amounts of nitrogen (the first number) than phosphorus or potassium. However, complete fertilizers sold for flowering plants (including roses and bulbs) such as 15-30-50 or 10-30-20 contain higher amounts of phosphorus (the second number) than nitrogen or potassium and are often labeled as “blossom or bloom booster”. The use of high phosphorus fertilizers originates from the need for phosphorus on agricultural fields heavily used for crop production which were deficient in phosphorus. However, most non-agricultural soils contain adequate amounts of phosphorus.

All three of the major nutrients are necessary for plant health. In general, Nitrogen is often required in the largest amount. Nitrogen is an integral part of chlorophyll manufacture through photosynthesis, stimulates green leafy growth and promotes fruit and seed development; Phosphorus supports the transfer of energy throughout the plant for root development and flowering; Potassium is essential for photosynthesis and regulates many metabolic processes required for growth, fruit and seed development.

Avoid Over-Applications of Phosphorus

Do home gardeners and landscapers really need to apply high phosphorus fertilizers to get gorgeous blooms?

Answer – it depends. Most non-agricultural soils (unless acid sandy) contain adequate amounts of phosphorus. A soil test is the only way to know for sure if a flower garden needs phosphorus.

What harm could it do to apply extra phosphorus?

Answer – Excess phosphorus (and potassium) can be detrimental to the environment by moving in runoff water and posing a threat to water quality. Aquatic plants are limited by phosphate and the addition of phosphate will induce algal blooms (eutrophication). Algal blooms are followed by increased bacterial activity, resulting in lowered oxygen levels and the eventual death of fish and other animals.

Also, high levels of phosphorus, either from chemical fertilizers or natural sources such as bone meal or rock phosphate, can inhibit growth of beneficial soil organisms called mycorrhizal fungi. Without beneficial organisms, plants must put additional resources into root growth at the expense of other tissues and functions.

Nitrogen is much more likely to be limiting in gardens. Nitrogen deficiency is characterized by overall leaf yellowing (chlorosis). Among other things, the lack of nitrogen reduces the plant’s ability to take up phosphorus. When nitrogen is restored to optimal levels, the plant’s ability to use phosphorus from the soil is markedly improved. It’s important to realize that when nitrogen is deficient it does not necessarily follow that other nutrients must be deficient as well.

So, don’t guess, soil test. The UMass Soil and Plant Nutrient Testing Laboratory offers soil testing for landscapes and gardens.

Once you receive your soil test report and recommendations from the UMass Extension Soil Test Laboratory:

  • Calculate the square foot area of the flower garden.
  • Calculate how much fertilizer to use.
  • Apply limestone, if needed according to the soil test recommendation.
  • Apply fertilizer based on the recommendation and calculation described below.

How to Calculate the Square Foot Area of the Flower Garden

For flower beds, lime and fertilizer recommendations by the UMass Extension Soil Test Laboratory are provided for a 100 square foot area. Therefore, you need to determine the size of your garden before spreading lime or fertilizer. The length multiplied by the width of the garden will give you the total area. For example, a garden 5 feet wide and 10 feet across would be an area of 50 square feet. Often flower gardens are irregularly shaped and the square footage would need to be estimated.

How to Determine How Much Fertilizer to Use Based on Soil Test Recommendations

The numbers on a fertilizer bag refer to the percentage of nitrogen (N), phosphorus (P2O5) and potassium (K2O) (in this order).

To determine how much fertilizer to use, divide the lbs. of the specific fertilizer material recommended in the soil test result by the percent of that same material in the fertilizer being used. First, convert the number to its decimal form when using percentages in calculations.

For example:

The soil test recommends 0.25 lb. of nitrogen per 100 sq. ft. and you plan to use a 10-5-10 fertilizer, then this is how to figure how much fertilizer to use to supply 0.25 lb. of nitrogen.

Use of Organic Matter

The addition of organic matter to very sandy soils or those low in organic matter can be very beneficial. Organic matter will increase both the water and nutrient holding capacity of the soil, moderate soil temperatures, encourage earthworm and other soil organism activity, increase soil nutrient levels, enhance the soil’s structure and make it easier for plant roots to penetrate the soil. Sources of organic matter include peat moss, leaf mold, rotted manure, bagged humus or compost. The use of organic mulch such as straw or bark mulch will also add soil organic matter as it decomposes.

Care should be taken when using composts, manures or other materials that are potentially high in nutrients as a source of organic matter. Heavy continuous use of compost can lead to imbalances or excess levels of some nutrients after a number of years. As with any soil amendment, it is advisable to periodically test your soil for nutrient levels, pH and organic matter and adjust your fertilizer and organic matter applications accordingly.

Guidelines for How and When to Fertilize Flowering Plants

Use the amount of fertilizer recommended on the soil test report at the times of year listed below for the type of flowering plants being grown. Note that these are guidelines. Plant health, types of fertilizers, weather conditions, soil types and other factors influence plant nutrient needs and timing of application.

For new flower beds, work the fertilizer into the top 4 to 6 inches of soil before planting. For established plantings, spread the fertilizer evenly around the plants and lightly rake it into the soil, then water thoroughly. If possible, pull back the mulch around plants so the fertilizer is applied to the soil and not on top of the mulch.

Annuals – Apply fertilizer during flower bed preparation. Make a second application at the same rate 6 to 8 weeks later. Annual selections that will continue blooming into fall may benefit from a third application at the same rate made in late August.

Perennials and Ornamental Grasses (new plantings) – Apply fertilizer during flower bed preparation. Make a second application at the same rate 6 to 8 weeks later.

Perennials and Ornamental Grasses (established plantings) – Apply fertilizer when growth resumes in the spring. Perennials with long lasting foliage or extended bloom periods may benefit from a second application at the same rate 6 to 8 weeks later.

Spring Flowering Bulbs – Do not apply bone meal or other source of phosphorus unless a soil test indicates it is needed. Apply fertilizer as soon as new growth emerges in the spring. Also apply fertilizer at the same rate when preparing beds in late August or early September.

Summer Flowering Bulbs – Apply fertilizer at planting time or, in the case of hardy summer flowering bulbs, when growth resumes in the spring. Make a second application at the same rate after flowering for plants with short flowering periods. For plants with long flowering periods such as cannas and dahlias, make a second fertilizer application at the same rate in mid-July.

Roses – Make separate applications of fertilizer in May, June and July. Do not fertilize after mid-July as new growth may be encouraged. It most likely will not have time to harden off properly in the fall and will be very susceptible to winter kill.

Wildflowers – Wildflowers that are native to New England’s woodlands or meadows generally have low nutrient requirements. Apply fertilizer once in the spring as new growth begins, or during bed preparation.

Types of Fertilizers for Flowers

There are several ways to supply nutrients to flowering plants. These include granular chemical fertilizers, which may or may not be controlled-release, water soluble fertilizer and organic fertilizers. Controlled-release fertilizers are also called continuous feed, slow-release or timed-release.

Granular fertilizer formulations that are not controlled – release will generally supply nutrients to the plants for about 6 to 8 weeks. During periods of excessive rainfall or frequent irrigation, the nutrients may be leached out of the soil and fertilizer may need to be reapplied.

Controlled (Continuous) – release granular fertilizers consist of water soluble fertilizer that is encased in a semi-permeable resin coating. When they come in contact with water, small amounts of nutrients are released to the soil for use by the plant. The rate of nutrient release for most of these fertilizers is regulated by temperature. The warmer the temperature the faster nutrients are released. When the initial fertilizer has been depleted, fertilizer will need to be re-applied. Many of the products for use with flowers will supply nutrients for 3-4 months depending on the temperature and amount of moisture.

Some gardeners may also prefer to use water-soluble fertilizer formulations. Water-soluble fertilizers are purchased ready to use or as a concentrated powder or liquid fertilizer that is mixed with water and applied to either the soil, or to both the soil and the plant’s foliage. Since the nutrients are in a soluble form, they are subject to leaching (movement through the soil). Because these nutrients are available for only a short period of time, the label of a water-soluble fertilizer will direct you to apply it at more frequent intervals than when using a granular or controlled- release formulation. In the flower garden liquid fertilizer is useful for a quick boost or to supplement granular or controlled-release fertilizers when then they have been depleted. However, most gardeners prefer products that do not have to be constantly reapplied.

Organic fertilizers can also be used to supply nutrients to flowering plants. They can be purchased as complete fertilizers or for individual nutrients and as liquids or solid bulk forms. Organic fertilizers are often lower in nutrient analysis and solubility than synthetic fertilizers. So, they may need to be applied at higher rates and greater attention should be given to soil preparation during the initial stages of bed preparation to ensure uniform distribution. Thoroughly incorporate organic fertilizers into the soil.

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