Kale is a cool-weather crop that requires two months of cool weather to reach harvest.
Sow seeds indoors or outdoors 4 to 6 weeks before the last frost in spring or as soon as the soil can be worked.
Kale is commonly started indoors and transplanted into the garden when seedlings are 4 to 6 weeks old.
Kale is a hardy biennial plant grown as an annual. The leaves of kale are similar to cabbage. Scotch kale has crumpled and curly gray-green leaves. Siberian or blue kale is less curly and a bluer shade of green.
Kale Yield. Plant 4 to 5 plants per household member.
- Where to Grow Kale
- Kale Planting Time
- Planting and Spacing Kale
- Caring for Kale
- Kale Pests and Diseases
- Kale Harvest
- Kale Varieties to Grow
- Growing Kale: Information On How To Grow Kale
- How to Grow Kale
- Caring for Kale Plants
- When Is Kale Ready to Pick?
- Curly Kale
- When to Harvest Kale
- How to Harvest Kale
- How to Store Kale
Where to Grow Kale
Kale prefers rich, well-drained soil with a soil pH between 5.5 and 6.8. Plant kale in full sun; plant kale in partial shade in warm regions. For optimal flavor, grow kale in cool weather.
Start kale indoors in late winter for planting out in early spring.
Kale Planting Time
Kale is a cool-weather crop that can tolerate temperatures as low as 20°F. Kale does not tolerate heat. Direct seed or transplant kale so that it comes to harvest before day time temperatures exceed 80°F. In cool-summer regions, plant kale in early spring for summer to early fall harvest. In warm- and hot-summer regions, plant kale in late summer for harvest in late fall or winter. In mild-winter regions, kale can be sown in fall for winter harvest.
Planting and Spacing Kale
Sow kale seed ½ inch deep spaced 3 inches apart; thin plants to 12 inches apart when they are 4 to 5 inches tall. Space rows 18 to 24 inches apart. Set transplants with crooked stems up to the first leaves.
More tips: Kale Seed Starting Tips.
Caring for Kale
Water and Feeding. Keep kale well watered for sustained growth and to keep leaves from getting too tough. Add aged-compost to planting beds in advance of planting. Side dress kale with aged compost every 6 weeks.
Companion plants. Beets, celery, herbs, onions, and potatoes. Not pole beans, strawberries, tomatoes.
Kale Care. Mound straw around kale once it is 6 inches high to prevent plants from touching the soil; soil easily sticks to kale’s often crinkled leaves.
Container Growing Kale. Kale will grow in a 6-inch container. Plant kale on 8-inch centers in large containers. Move kale grown in containers into the cool shade when the weather warms to extend the season.
Kale Pests and Diseases
Pests. Kale can be attacked by cutworms, cabbage loopers, and imported cabbage worms. Control these pests by handpicking or spry with Bacillus thuringiensis.
Diseases. Kale has no serious disease problems.
Kale will be ready for harvest 55 days from transplanting, 70 to 80 days from seed. Cut individual leaves for use when the plant is 8 to 10 inches high; cut the outside leaves first. If you harvest the entire plant, cut 2 inches above the soil and the plant will sprout new leaves in 1 to 2 weeks. Harvest kale before it gets old and tough.
More tips: How to Harvest and Store Kale.
Storing and Preserving Kale. Leave kale in the garden until you are ready to use it. Its flavor will be sweetened by frost. Kale will keep in the refrigerator for 1 to 2 weeks in a plastic bag. Kale can also be frozen, canned, or dried.
Kale Varieties to Grow
Common name. Kale, borecole
Botanical name. Brassica oleracea acephala
More tips: Kale Growing Quick Tips.
Save Money Growing Veggies: KITCHEN GARDEN GROWERS’ GUIDE
Quick Guide to Growing Kale
- Plant kale 3 to 5 weeks before the last frost. In-ground gardens, raised beds, and containers are all excellent growing options.
- Space kale 18 to 24 inches apart in an area with full sun and well-drained, fertile soil with a pH of 6.5 to 6.8.
- Improve native soil by mixing in several inches of aged compost or other rich organic matter.
- Kale is a fast grower, so keep the soil moist by giving it 1 to 1.5 inches of water each week.
- Get the most out of your harvest by regularly feeding plants with a continuous-release plant food.
- For nutritious kale year-round, consider an indoor, water-based growing system.
- Harvest kale starting with the lowermost leaves once they reach the ideal color and are large enough to eat. Leaves reach their peak flavor once they’ve been kissed by a light frost.
Soil, Planting, and Care
Set out plants in spring 3 to 5 weeks before the last frost; in late summer, you can begin planting kale 6 to 8 weeks before the first frost for fall and winter harvests, and continue planting throughout the fall in zones 8, 9, and 10. Be sure to choose kale starter plants from Bonnie Plants®, so you know they’ll be strong and vigorous.
Kale grows best in full sun, but will tolerate partial shade as well. Plants that receive fewer than 6 hours of sun daily will not be as stocky or leafy as those that get ample sun, but they will still be plenty edible! Like collards, kale likes fertile soil to grow fast and produce tender leaves. Enrich the soil with compost and fertilizer before setting out the seedlings. Apply fertilizer and lime according to test recommendations. If you forgo the soil test, work nitrogen-rich amendments such as blood meal, cottonseed meal, or composted manure into the ground before planting.
The soil pH should be 6.5 to 6.8 to discourage clubroot disease, although the plants will grow fine in a pH of 6.2 to 6.8 if clubroot is not a problem in your garden. To be sure about your soil pH, test the soil with a do-it-yourself kit, or by using your regional Cooperative Extension office. If that seems too complicated, you can simply improve your existing soil by mixing in a few inches of Miracle-Gro® Performance Organics™ All Purpose In-Ground Soil with the top layer. Enriched with aged compost, it will improve both the texture and nutrition of the native soil.
Kale is easy to plant, and grows beautifully in both raised beds and containers. To create the ideal growing environment for the plant roots, fill raised beds with 100 percent organic Miracle-Gro® Raised Bed Soil and containers with Miracle-Gro® Performance Organics™ All Purpose Container Mix. Set plants at the depth at which they are growing in the container. Space them 18 to 24 inches apart. The leaves will grow bigger if given a lot of space, but smaller leaves tend to be the most tender.After planting, water plants well. Plants grow best when they have access to both great soil and a continuous source of nutrition, so apply a water-soluble fertilizer such as Miracle-Gro® Performance Organics™ All Purpose Plant Nutrition regularly for excellent results.
At this point you may need to be patient, because spring-planted kale may stay small until slightly warmer soil temperatures trigger vigorous growth. Kale planted in late summer or early fall may sulk through spells of hot weather. Then, when conditions improve, the plants will take off, quickly multiplying in size.
Kale likes a nice, even supply of water, about 1 to 1.5 inches per week. You can measure how much water rain has provided by using a rain gauge in the garden. Mulch with compost, finely ground leaves, weed-free hay, straw, pine needles, or finely ground bark to keep the soil cool and moist and to keep down weeds. Mulching will also help keep the leaves free of splashing soil for a clean harvest.
You also have the option of growing kale indoors. An easy way to do that is in a hydroponic growing system like the Miracle-Gro® Twelve™ Indoor Growing System. There’s no soil—plants grow directly in water that circulates around the roots, delivering moisture, nutrition, and air. With plenty of light courtesy of a grow light, the system provides top-notch growing conditions for kale. Best of all, you won’t even have to go outside to harvest.
Growing Kale: Information On How To Grow Kale
If you have a vegetable garden, consider planting kale. Kale is very rich in iron and other nutrients, like Vitamins A and C. When it comes to healthy eating, kale should definitely be included in your diet. Kale plants are extremely robust, adaptable to many different situations, and will grow in winter. Growing kale can be done in all types of soil, although they prefer sunny, well-drained areas.
How to Grow Kale
Although kale is quite versatile, there is a proper way for planting kale in the garden in order to attain the healthiest growth. Kale prefers well-drained soil in sunny locations but will tolerate shade too.
This means you should choose your garden area wisely, as kale grows best when planted after the soil reaches temperatures of 60 to 65 F. (16-18 C.). However, hot weather can turn it bitter, so you may want to mulch the ground to protect from too much heat and to keep down weeds. Likewise, you can opt for a somewhat shadier location in regions where extreme heat may be an issue, or even where sun just isn’t that plentiful.
When planting kale, start the plants indoors to get a jump early in the season. Growing kale isn’t too demanding. Simply cover the kale seeds with 1/2 inch of soil and keep moist to germinate. After all chance of frost has passed, transplant the seedlings into the ground.
In late summer or early fall, you can also direct seed kale plants outdoors. Cover the seeds with 1/2 inch of soil. Don’t cultivate around the seed area until the seedlings appear, then do so only when necessary, as you don’t want to disturb the roots.
Caring for Kale Plants
Keep the ground well watered and, as your kale grows, hoe the soil shallowly around the plants, removing any weeds starting to grow.
Growing kale is pretty simple, and plants take only about two months to mature. Since they take so little time, you can start a couple of batches early, a couple more later in the summer, and a couple in the fall. This succession planting provides you with fresh kale plants to pick from for about six months or so.
When it comes to picking kale, simply harvest the young leaves from the bottom of the plant up. Being able to pick kale all season long is definitely a plus to growing this hardy vegetable.
Go-to green: Kale is in fashion. Photo: Peter Stoop
Where did the superfood kale come from? V. Chan
Only three words should come after super. Man. Phosphate. Annuation.
Kale is a northern British word for Brassica oleracea var acephala, which basically means cabbage without a head. During the Middle Ages kale was the go-to green leafy vegetable. It was easy to grow, fairly frost resistant and a healthy addition to any mealy gruel. At the end of the Middle Ages kale mutated to develop a “head” and so cabbages were born. Stone-walled kailyards can still be found in the Scottish highlands. In southern England kale was known as “cole” or “colewort”. Colewort was transformed in the southern states of the US to “collard”, as in “black-eyed peas and collard greens”.
Although I loathe elevating any ostensibly peasant food into the Superfood Halls of Justice I will say that I lived on kale and lentil soup when I was living in Scotland for two years. I washed it down with Scottish ale and single malt whisky and have never been healthier.
I try to make my own frozen dinners but they have dry, discoloured spots and the meat looks mummified. B. McKenna
You have what is called freezer burn, in which water escapes from the food to the air surrounding it in the form of ice crystals, effectively freeze drying the food. Follow the lead of frozen dinner manufacturers, who carefully cover any meat in a layer of thick sauce or gravy. Don’t spread your food out, instead arrange it in compact piles to reduce surface area and therefore air contact. Cover tightly with plastic film and aluminium foil, and label with date and contents.
I have recently been diagnosed with an allergy to alliums and my work is organising a lunch at an Italian restaurant. What should I do? S. Wilson
You could take a container of brown rice and fork it into your mouth defiantly in the corner but I assume you want to get on with your colleagues. Allium is the botanical genus that contains garlic, leeks, onions and shallots. So going to an Italian restaurant could possibly drive fear into your heart with no way of avoiding cramps and pain after eating – right? Give the restaurant a ring. Although Italians are genetically programmed to put garlic in everything they are also one of the most hospitable races on earth, plus they are exceptionally creative cooks who will be able to navigate a course for you around their dishes. My partner has this problem. We always call ahead and it’s rarely a hassle.
Why does some cheese go stringy when you heat it and some not? B. Chovanec
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Some cheeses are made in an acid environment either by adding acid to make the milk curdle or by using lactic cultures. This acid stops the calcium from helping the protein to form long, ropy strands and instead come together to form clumps. When you heat these types of cheeses, such as Indian paneer or Italian ricotta, they lose moisture but the proteins hold tight. Other cheeses, such as mature cheddar or parmesan, don’t become stringy when you heat them because the enzymes have broken down those long, ropy protein chains as the cheese matures.
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Kale, (Brassica oleracea, variety acephala), loose-leafed edible plant derived from the cabbage of the mustard family (Brassicaceae). Kale is grown mainly for autumn and winter harvest, as cold improves its eating quality and flavour; its hardiness permits harvest of fresh greens after most fresh vegetables have become unavailable. The leaves can be eaten fresh or as a cooked vegetable and are a source of vitamin A, vitamin C, calcium, iron, and vitamin B6.
Kale plants produce a rosette of elongated leaves with wavy to frilled margins. The leaves are typically blue-green in colour but can also be light green, red, or purple, depending on the variety. In a long growing season the main stem reaches a height of 60 cm (24 inches) or more. The plant may be harvested by cutting off the entire rosette before the stem has elongated, or (especially in areas with long, cool growing periods) the individual lower leaves may be removed progressively as the main stem elongates. Though usually grown as an annual, kale is a biennial plant and produces yellow four-petaled flowers borne in loose clusters in its second year. The fruits are dry capsules known as siliques.
Who knew a vegetable could be so cool? Although kale has early roots in Greek and Roman culture, it remained a relatively minor commercial crop in the U.S. until recent years. This leafy green reached celebrity status around 2012, appearing on menus of Michelin star restaurants and becoming the choice ingredient of millennial food bloggers. Kale displaced other greens in salads, soups, and pesto, and even showed up in the snack aisles as chips. Bon Appétit magazine named 2012 the year of kale, and on October 2, 2013, “National Kale Day” was launched in the U.S.
While curly and lacinato (also known as dinosaur or Tuscan) are generally the most common types of kale, this vegetable comes in a wide variety—each with its own unique colors, flavors, and textures: redbor is characterized by its deep purple, curly leaves; the blue-green and purple-red leaves of red Russian are known for being semi-sweet; the large green leaves of Siberian are particularly cold weather-hardy; and Chinese kale (Gai Lan), or “Chinese broccoli,” can be used in place of conventional broccoli in many dishes. Like broccoli, kale is part of the Brassica oleracea family, which also includes cabbage, cauliflower, bok choy, collard greens, and Brussels sprouts. Another more commonly recognized name for this vegetable family is Cruciferae or cruciferous, which refers to the shape of its sprouts that resemble a cross.
- Vitamin K
- Vitamin C
- Vitamin A
- Carotenoids lutein and zeaxanthin
- Vitamin B6
Kale and Health
Cruciferous vegetables contain a plant chemical called glucosinolates, sulfur-containing compounds that are broken down into isothiocyanates and indole-3-carbinol after chewing, chopping, or cooking. In nature, glucosinolates act as a first-line defense for plants, protecting them from environmental and biological stresses (insects, fungi, drought conditions). These same substances are being researched for their proposed ability in humans to affect chronic conditions including certain types of cancer and heart disease. Laboratory studies have shown that isothiocyanates and indole-3-carbinol inhibit inflammatory processes, prevent the growth and spread of tumor cells, and protect healthy cells.
Observational studies that follow groups of people over time have sometimes suggested a protective effect of cruciferous vegetables on various cancers and cardiovascular health, but findings have not been consistent. There are several possible reasons for this discrepancy. The use of different study designs and methods, as well as the way in which the vegetables were cooked can change the bioavailability of isothiocyanates and their effects on the disease process. Genes may also play a role, as some people metabolize isothiocyanates more efficiently than others. It is also possible that the amounts of cruciferous vegetables consumed by study populations have no important impact on disease risks. More research with larger and longer-term studies is needed.
Regardless, kale remains a highly nutritious food to include as part of a healthful dietary pattern. The 2015-2020 Dietary Guidelines for Americans recommend that adults eat a variety of vegetables as part of a healthy meal plan, and specifically at least 1½ cups of dark-green vegetables (including cruciferous) per week.
People who are placed on blood thinners or anticoagulant medication to prevent blood clots are sometimes concerned about eating kale and other green leafy vegetables that are rich in vitamin K. Vitamin K has a unique action that assists in clotting blood, and can interfere with the effects of some blood thinners. However, people taking these medicines can safely eat these vegetables with a general precaution: eating a relatively consistent amount from day to day can allow one’s physician to adjust the dose of medication to balance the dietary intake of vitamin K, and should not interfere with the anticoagulant medication’s effectiveness. For those who are on blood thinners or anticoagulant medications, it would be wise to check with their physician and possibly a clinical dietitian.
Another concern has been the goitrogen content of kale and other cruciferous vegetables. Goitrogens are naturally occurring substances that can block iodine from entering the thyroid gland. Iodine is a trace mineral needed by the body to make thyroid hormones that promote normal metabolism. A deficiency of iodine can lead to a condition called goiter, or enlargement of the thyroid. Healthy persons who eat enough iodine and metabolize iodine normally will not be affected by dietary goitrogens. However, if one has an underactive thyroid called hypothyroidism and cannot produce enough thyroid hormone, eating excess goitrogens, especially in raw form, may further suppress thyroid activity and increase the risk of goiter. Those who have hypothyroidism specifically due to an iodine deficiency are at greatest risk. A simple solution is to cook cruciferous vegetables, which deactivates the enzyme responsible for causing the goitrogenic effect. Including a wide variety of vegetables each week other than cruciferous will also protect against eating an excess amount of goitrogens.
- Available throughout much of the year, Kale is even tolerant to frost and cold weather. Low temperatures can actually cause kale and other cruciferous vegetables to convert starch molecules into sugar, resulting in a sweeter, less bitter flavor.
- Despite their tough and fibrous texture, kale stems are edible if cooked.
- Cut stems into small pieces and add to a stir-fry.
- Add diced stems to soups.
- Use to make a vegetable stock.
Kale has hearty leaves that withstand all types of cooking: boiling, braising, steaming, microwaving, and stir-frying. Kale can also be served raw but the texture may be difficult to chew.
- Sautéed Kale: This is one of the simplest, quickest methods to enjoy kale. Add 2-3 tablespoons of olive oil to a saucepan on medium-high heat. Add 2 cloves of minced garlic and cook for 1-2 minutes until softened. Add ½ cup water or broth and 1 – 1½ pounds kale (washed, stems and leaves coarsely chopped). Cover the pan and allow to cook for 5 minutes until kale is softened and at desired texture. Season with herbs and spices as desired.
- Kale Chips: Preheat oven to 350 degrees F. Line a baking sheet with parchment paper. Wash and dry 1 bunch of kale thoroughly; use paper towels to blot if needed. Using your hands, pull leaves from their stems and rip into small pieces; or you may use kitchen shears to cut leaves from stem and into small pieces. Place into a large bowl and drizzle with oil. Massage oil evenly into kale pieces. Spread in single layer on baking sheet. Sprinkle herbs or spices as desired (try curry, cumin, garlic powder, onion powder, smoked paprika, nutritional yeast, or chili powder). Bake until the leaves shrink and the edges turn slightly brown, about 15 minutes.
- Kale Pesto: This recipe uses walnuts instead of the classic but more expensive and obscure ingredient of pine nuts. Place into a food processor: 2 cups kale leaves (stems removed), ¼ cup extra virgin olive oil, and 2 cloves garlic or ¼ teaspoon garlic powder; pulse until smooth. Add ¼ cup toasted walnuts, and pulse until blended. Add ½ cup Parmesan cheese and pulse again until blended. Serve pesto mixed into pasta or whole grains, as a sauce for chicken or fish, as a pizza sauce, or spread on crackers.
- Kale Salad: If using in a salad, there are two methods to soften the leaves so they are easier to chew: 1) Place leaves in a bowl and drizzle with olive oil; massage the leaves for 1-2 minutes, or 2) Blanch leaves by placing in a pot of boiling water for 1 minute. Drain the leaves and place into a bowl filled with ice water to quickly stop the cooking. Place leaves in a colander and gently press out excess water. Use paper towels to blot dry as needed. Blanching can also help to remove some of the bitter flavor from kale.
Three-Green & Wheat Berry Salad with Mushroom “Bacon”
More recipe ideas and serving suggestions featuring kale:
- Add kale leaves to soups, stews, and casseroles at the start of cooking.
- Add a few handfuls of chopped kale into a burger mixture before cooking.
- Use large hardy lacinato kale leaves as a wrap to replace bread or tortillas.
- Add a handful of kale leaves to smoothies.
- Kale with Carmelized Onions
- Three-Green & Wheat Berry Salad with Mushroom “Bacon”
- Garlic-Braised Greens
- White Bean and Kale Hummus
Did you know?
- Prior to its dramatic rise to popularity in edible form, kale leaves were most commonly used in restaurants as decorative garnishes.
- Some types of kale offer white, lavender, blue, pink, or purple leaves that are used in floral bouquets.
- Thomas Jefferson was a kale aficionado, growing and recording several varieties of kale in his garden at Monticello in the early 1800s.
The contents of this website are for educational purposes and are not intended to offer personal medical advice. You should seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this website. The Nutrition Source does not recommend or endorse any products.
When Is Kale Ready to Pick?
When to Pick Kale Sprouts
Kale sprouts are ready to pick almost as soon as you see the first two little “leaves” appear. When planted, the seeds should have been spaced so tightly that you see a solid sheet of leaves covering your container. These first leaves, called the cotyledon, nourish the plant until the true leaves appear, but kale sprouts should be picked before the true leaves form.
When to Pick Baby Kale
Baby kale should be picked while the leaves are still smaller than your hand. The approximate number of days from planting to the date when you can begin picking baby kale for some of the popular varieties of kale are:
- Vates Blue Dwarf – 30 days
- Lacinato/Toscano – 30 days
- Winterbor – 28 days
When to Pick Mature Kale
Different species of kale reach maturity at different times, and kale sprouts and baby kale are harvested before reaching maturity. Your kale is mature when the leaves reach the size of your hand. The approximate number of days from planting to the day you can begin picking mature kale for some popular varieties of kale are:
- Dwarf Blue Curled – 55-60 days
- Dwarf Green Curled – 50-60 days
- Improved Dwarf Siberian – 50 days
- True Siberian – 70 days
- Red Ursa – 65-70 days
- Redbor – 55-65 days
- Lacinato – 60-80 days
- Winterbor – 52-60 days
- Toscano – 65 days
- Red Russian – 50-60 days
- Vates Blue Curled – 55-56 days
- Siberian – 60-70 days
- Winter Red – 50 days
- Ripbor – 65 days
Preserving Kale for Winter Use
Like spinach, kale can be frozen or canned, but it can also be dried and crumbled or powdered. Follow these directions to dry your kale:
- Wait until the sweet flavor of the kale has been enhanced by one or two weeks of morning frosts, then pick it. If this will be your last harvest for the season, cut the plant off of the stalk.
- Rinse and soak the leaves and briefly allow the leaves to dry in your colander.
- Remove the stems and veins and discard them or dry them separately because they require a longer drying period.
- Place the leaves on your cutting board, and, using a sharp knife, chop the leaves into fine strips.
- Stack the strips on top of each other, roll them up as you would roll a jelly roll, and chop them up into slivers no larger than 1/8″.
- You can dry small batches overnight in your oven using just the oven light, but a dehydrator is best for preserving large batches for the winter.
- You also dry kale in the oven by setting the temperature below 145°F (63°C) and turning the kale over hourly.
- In a dehydrator, dry the leaves or the stems and veins on medium until they are crisp, brittle, and crumbly. If any moisture remains, continue drying.
- Once they are dry, allow the leaves to cool to room temperature, and store them in glass jars. Make sure that the lids fit tightly. You can store your dried kale as slivers, crumble it, or even powder it.
Kale is a versatile vegetable, whether you grow it as sprouts, baby kale, or mature kale. When considering how to use your kale, remember that the smaller the leaf, the milder the flavor. In general, you will probably want to use smaller leaves for salads and larger ones for soups and stews. Try some of these serving ideas.
Ideas for Serving Kale Sprouts
You can toss your kale sprouts into a salad, use them as a garnish, use them as a seasoning, lightly roast them, or sauté them and serve them as a side dish with your entree.
Ideas for Serving Baby Kale
You can use baby kale leaves whole or chopped. Use them in your recipes as a substitute for spinach or other greens, or chop them up to add a twist to your seasonings. You can also serve them fresh in a salad, or apply the seasoning of your choice and roast them until they become crispy to create kale chips for snacking.
Ideas for Serving Mature Kale
Baby kale has a milder, sweeter flavor than mature kale. Massaging mature leaves or those grown in summer’s heat can restore some of the sweet flavor. You can also remove the plant’s tougher stems and veins from the leaves or eat them, as you prefer.
While the flavor of mature kale leaves might be too strong for a salad, you can add them to soups, stews, and other dishes, especially as a substitute for spinach.
Light requirements: Full sun is ideal, but plants yield in part shade. Protect plants from strong afternoon sun in warmest regions.
Planting: Space 12 to 24 inches apart, depending on type. (Read the stick tag that comes with the plant for specific spacing recommendations.)
Soil requirements: These greens need moist, nutrient-rich soil. Amend soil with 4 to 6 inches of compost or other organic matter prior to planting. Soil pH should be 6.5 to 6.8.
Water requirements: Keep soil consistently moist throughout the growing season. Aim for 1 to 1.5 inches of water per week through rainfall or irrigation. Mulch soil to reduce water evaporation and keep leaves clean from splashing soil.
Frost-fighting plan: Established plants tolerate hard frosts (temperatures below 28º F) and produce new leaves all winter long in zones 7 to 10. Frost-kissed leaves boast sweeter flavor. Protect newly planted seedlings from late spring or early fall frosts by covering plants with a frost blanket.
Common issues: Watch out for cabbageworms, harlequin bugs, slugs, grasshoppers, and cabbage aphids. Kale is a cole crop, so clubroot can attack plants. Kale can be slow to take off in the garden. Spring plantings may linger until soil warms; fall crops can stall a bit with warm air.
Harvesting: Harvest leaves when they are up to 10 inches long. Younger, shorter leaves have the mildest flavor. Pick lower leaves first, and the plant will continue to produce new upper leaves.
Storage: Refrigerate unwashed leaves in a lightly damp paper towel slipped into a very loosely closed plastic bag and store up to 5 days.
For more information, visit the Kale page in our How to Grow section.
Kale is ready for harvest as soon as the leaves are large enough to eat. Kale matures 55 to 75 days from seed sowing. It is best grown to mature in spring or fall before temperatures climb into the 70°sF . In mild-winter regions, kale will produce new leaves nearly all winter.
When to Harvest Kale
- Harvest kale as soon as the leaves are large enough to eat. Pick large, outside kale leaves first; leave the center ones to grow on.
- Regular harvest and even watering will keep kale plants producing new tender leaves for several months—as long as the weather stays cool.
- Kale leaves will be sweeter if harvested after frost; cool temperatures cause carbohydrates in the leaves to turn to sugar.
- Kale can survive but not thrive where winters are cold; plants can withstand temperatures as low as 14°F (-10°C).
- In hard freeze regions, grow kale under row covers, plastic tunnels, or in cold frames. When temperatures in the teens are predicted, cover plants to keep the leaves from freezing. Still, frozen leaves can be cooked.
- Kale planted in the spring and grown into the summer will be bitter if hit by summer heat. When summer comes keep roots cool by mulching around plants and make sure plants are well watered; these efforts will improve flavor.
Cut kale leaves as needed (called cut-and-come-again) new leaves will grow from the center of the plant.
How to Harvest Kale
- Cut kale leaves one-by-one as needed with garden scissors or knife or cut away the whole head. If you cut kale leaves as needed (called cut-and-come-again) new leaves will grow from the center of the plant.
- After harvesting kale, wash the leaves thoroughly to remove any soil that may be clinging to the leaves.
How to Store Kale
- Kale will store for two to three weeks at 32° to 34°F (0°-4°C) and 90 to 95 percent humidity (moist) with some air circulation.
- Wrap leaves in a moist cloth or paper towel and store them in a perforated plastic bag in the vegetable crisper of the refrigerator; this will keep leaves from drying.
- If you cook the whole leaf, the stems will become tender.
More tips: How to Grow Kale.