By: Amy Grant
Kale has become extremely popular, notably for its health benefits, and with that popularity has come an increase in its price. So you might be wondering about growing your own kale but perhaps you lack garden space. What about container grown kale? Will kale grow in containers? Read on to find out how to grow kale in containers and other information on potted kale plants.
Yes, kale (Brassica oleracea) will grow in containers, and not only that, but it’s easy to grow your own potted kale plants and they don’t need much space. In fact, you can grow one or two kale plants in a pot along with your annual flowers or perennials. For a bit more drama, you can add colorful Swiss chard (Beta vulgaris) into the mix for another supply of healthy greens.
If you comingle the kale with other annuals and perennials, be sure to use those that have the same requirements in light, water, and fertilization.
Kale is a biennial, cool weather crop that will grow in a container year-round in many regions, except during the hottest part of the summer. Kale is suited to USDA zones 8-10.
Choose a sunny location for the container with at least 6 hours of direct sun when growing kale in pots. Kale plants require rich, well-draining soil with a pH of 6.0-7.0.
Choose a pot with a diameter of at least a foot (.3 m.) across. For larger containers, space the plants 12 inches (30 cm.) apart. Use a good quality potting soil (or make your own). You can directly seed after all danger of frost has passed for your region in the spring or you can plant seedlings.
Although kale needs sun, it can wilt or die if it gets too much, so mulch around the base of the plants with straw, compost, pine needles or bark to retain moisture and keep the roots cool.
Keep the kale watered with 1-1 ½ inches (2.5-3 cm.) of water per week; the soil should be moist down to an inch into the soil. Since potted plants dry out faster than those in the garden, you may need to water container-grown kale more often during hot, dry periods.
Fertilize with a tablespoon of 8-4-4 water-soluble fertilizer mixed into one gallon of water once every 7-10 days when growing kale in pots.
Many pests can affect kale, so here are some tips that should help:
Harvest the kale from the bottom of the stalk upward, leaving at least four leaves on the plant for continuous growth. If you have planted the kale in amongst other decorative, flowering plants and this looks unsightly to you, remove the plants and reseed or tuck in new kale seedlings.
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Both kale (Brassica oleracea) and chard (Beta vulgaris var. cicla) are biennial cool-weather crops that grow well in pots all year round except for the hottest part of summer, but chard tolerates the heat better than kale. These leafy greens require similar care, and both produce the sweetest, mildest leaves during cooler weather. The colorful stems of chard look attractive in pots, while kale produces yellow flowers during warm weather. You can plant them together in a large planter or separate them into individual pots. Kale and chard grow in U.S. Department of Agriculture plant hardiness zones 8 through 10 and 5 through 10, respectively.
Grow kale and chard in pots with at least a 12-inch diameter. If you use a large planter, space plants 12 inches apart. Use well-draining standard potting mix with a pH between 6.2 and 6.8.
Place the pots in areas that receive at least six hours of direct sunlight daily. Kale can also grow in areas with partial shade.
Apply 1 or 2 inches of straw, compost, finely ground leaves, pine needles or finely ground bark to the soil around the base of the plants to keep the soil cool and moist.
Water kale and chard with at least 1 to 1 1/2 inches of water per week. The soil should feel moist at a depth of 1 inch. Water more often during hot, dry periods.
Fertilize kale and chard with 1 tablespoon of 8-4-4 water-soluble fertilizer mixed into 1 gallon of water once every seven to 10 days. Use the fertilizer in place of water, and pour it onto the soil slowly until it drips through the bottom of the pot.
Spray the kale and chard plants with insecticidal soap once a week if you notice aphids or mites. Hand pick and destroy caterpillars. Spray the kale plants thoroughly with bacterial thuringiensis (Bt) if you notice cabbage moths or worms on or near the plants. Use it as often as needed. Cover kale plants with tulle in late summer to protect it from harlequin bugs, if necessary.
Harvest kale leaves from the bottom of the stalk upward. Leave at least four leaves on the plant to continue growth. Harvest the outer chard leaves, leaving the center ones to continue to grow.
Melissa Rae has been a writer since 2008, specializing in home-and-garden, business, technology and education topics. Rae holds a Bachelor of Science in business administration from Herzing University.
Kale is a particularly easy and rewarding crop for the home gardener. It’s a nutritional powerhouse, rich in vitamins A, C and B6, as well as, minerals and dietary fiber. It’s also a long-lived low-maintenance crop, cold hardy and not very prone to disease. Last but not least it’s versatile, adding nutrition and flavor to many different dishes.
Kale is a heavy feeder with an appetite for nitrogen. Organic growers should add plenty of compost or well-rotted manure to their soil. Kale can be direct-seeded or transplanted outside up to 5 weeks before the date of the last expected spring frost and succession-planted until 6 weeks before the first expected fall frost. It will produce over a long season, but its flavor is best after fall frosts increase the sugar content of leaves.
Spacing will depend on how you want to use your kale. Baby kale for salads or juicing can be sown 1″ apart in furrows spaced 4″ apart, or on a 2″ grid in a bed. Mature kale for cooking requires more space–allow 12″ between plants for smaller varieties like Red Russian, 18″ or more for larger plants like Winterbor.
Plant kale seeds 1/4″ – 1/2″ deep in moist soil, in a space where it will receive at least 5 hours of sun every day. In hot climates summer-sown kale will benefit from afternoon shading.
Kale is a fairly hardy crop, but there are still some pests and diseases that may occur.
Curled, puckered, yellow leaves may be a sign of aphid infestation. Look on the undersides of leaves for soft-bodied green, brown or pink insects about the size of pinheads. Aphids can be handpicked or killed with organic insecticidal soap. Ladybugs eat aphids.
Ragged holes in leaves may be caused by cabbage loopers or cabbage worms, light green yellow-striped caterpillars. Handpick them or spray with Bacillus thuringiensis.
Tiny pinholes in your leaves may be the work of flea beetles, tiny black jumping beetles that are very hard to handpick. Skeletonized leaves may be caused by the Mexican bean beetle. Leaves chewed to the stem suggest the presence of vegetable weevils. Pyrethrum spray may control these pests. Pyrethrum is organic but toxic to bees–spray it in the evening when pollinators aren’t active. Curly kale may be less susceptible to beetle damage than flat-leafed kale.
Powdery mildew is more apt to strike kale seedlings in the greenhouse than outdoor kale. Dusty gray spots spread rapidly over the leaves and the plants are weakened. Prune off infected leaves, dipping your cutters in a bleach-and-water solution after each cut, or spray with organic fungicides. Curly kale is less susceptible than flat-leafed kale.
Black leg causes sunken areas to develop around the stem near the ground and gray spots to appear on leaves and stems. The whole plant may wilt and die. This is hard to cure. Remove and destroy (do not compost) infected plants.
Flat-leafed kales like White and Red Russian are prized for their tenderness and flavor, but they are susceptible to pest and disease problems as noted above.
Curly kales like Vates and Winterbor are highly productive and more cold-hardy, pest-resistant and disease-resistant than other kale varieties.
Dinosaur kale or Tuscan kale has crinkly smooth-edged leaves and excellent flavor. It is not very cold hardy–leaves may be ‘burned’ by temperatures in the twenties.
image from morguefile: http://mrg.bz/mSH9IO
Young leaves may be eaten raw in salads or juiced. Older leaves are best cooked. Here are a few cooking suggestions, and really our favorite ways to eat kale:
If you like steamed kale, try mixing them with cheese and pesto for lasagna filling. Or, make a kale pesto! Add them to fried rice along with onions, eggs and soy sauce. Kale can be thrown in just about anything as you are cooking.
Using kale in salads is one of our favorite ways to use kale from the garden, specifically with an Asian dressing or seasonings. This is a great side dish that is really easy. You can add apples and cheeses. But it can stay simple, too, with a light Asian dressing.
Make “kale chips” by tearing leaves into pieces, drizzling them with olive oil and salt and baking them on paper-lined cookie sheets at 350 – 375 F for 5-7 minutes. This makes a great cooking project with children.
Kale and other members of the brassica family should not be planted near tomatoes because they can stunt the growth of the tomatoes. Brassica plants include arugula, bok choy, broccoli, broccoli raab, Brussels sprouts, cabbage, cauliflower, honesty, horseradish, kohlrabi, radishes, rutabaga, sweet alyssum, turnips, and watercress.
Yes, kale can be grown in containers. Each plant needs a container at least 12 inches wide by 12 inches deep filled with good quality potting soil. Find a sunny place for your kale plants where they will get at least six hours of sun each day. Give potted kale plants one to one and a half inches of water per week, keeping the soil moist to a depth of one inch. Kale growing in containers should be fertilized every seven to 10 days with a water-soluble 8-4-4 fertilizer mixed into water.
The flowering stalks of the kale plant are edible and are especially sweet. You may see them available for sale at farmer’s markets as kale raab. Similarly, broccoli raab is the flowering stalk of the broccoli plant.
Although kale is normally grown as an annual plant, it is actually a biennial, which means it has a two-year life cycle. In its first growing season, your kale plant will produce lots of leafy green foliage. In USDA hardiness zones 7 through 10, it will keep producing new leaves throughout the winter. Kale that survives through the winter and enters its second year will soon bolt, producing a flowering stalk that creates seeds.
Kale is categorized as having roots of medium depth, which means the plants need 18 to 24 inches of vertical space to really thrive. However, you can have success growing kale plants in containers as long as the container is at least 12 inches deep and 12 inches wide.
Kale needs one to one and a half inches of water per week, which should keep the soil where it’s growing moist to a depth of at least one inch. If you’re not sure whether your kale plants need to be watered, there is an easy way to check the moisture level of the soil. Just stick your finger into the soil about an inch deep near where your kale plants are growing. If the soil feels damp or sticks to your skin, it is still moist, and it isn’t yet time to water your kale plants again.
Kale needs at least six hours of direct sunlight each day in order to thrive. During especially hot seasons, your plants will benefit from partial shade, especially during the hottest part of the day.
When kale is harvested carefully, it works as a cut and come again vegetable that grows back to regenerate its leaves for multiple harvests. For your kale to grow back, harvest the oldest leaves first—the ones on the outside of the plant at the base. Use clean, sterilized shears to clip the leaves from the plant along with their stem. As long as you remove the stem along with the leaves and harvest the oldest leaves first, your plant will keep producing more leaves to replace the ones you’ve harvested.
Kale is categorized as a plant with roots of medium depth, and the root system extends 18 to 24 inches into the soil. That said, you can successfully grow kale in a container as long as the container is at least 12 inches deep by 12 inches wide.
Most gardeners begin to harvest their kale once leaves have grown to be as big as a person’s hand. That said, kale can be harvested at practically any stage, from tiny microgreens to baby kale to fully mature leaves. You can begin harvesting kale leaves as soon as they are large enough to make cooking them or including them in a salad worthwhile. Even when you thin out your kale plants as they grow from seedlings, the baby plants you cull from your rows can be included in a salad or stir fry.
From the day seeds are planted, it takes kale between 70 and 80 days to mature until it’s ready for harvesting. If you count from the date young plants are transplanted into the garden, it takes kale 55 days to be ready to harvest.
Kale performs best when it gets full sun or light shade, with shade especially benefiting plants when the weather gets hot. It needs at least four hours of sun each day. (Light shade means plants get four to six hours of sun per day, and full sun means plants receive six or more hours of sun per day.)
Kale seeds should be sown three inches apart, and thinned once they reach between four and five inches tall to have 12 inches of space between plants. Grow kale in rows that are spaced 18 to 24 inches apart.
Kale plants can typically be harvested 25 to 30 days after planting and can harvest again every four to five weeks throughout the growing season and again in the fall. In cool climate areas, you can continue to harvest kale year round.
Keep kale watered with one and a half inches of water once aper week. Provide a deep drink once per week instead of multiple smaller waterings. If you live in a dry or hot climate, or are experiencing drought in your area, you may need to water kale plants two or three times per week.
Different varieties of kale reach different heights on average, but as a general rule, kale plants grow between 12 and 30 inches tall. Kale plants grow to reach widths between eight and 12 inches, on average.
Kale is most often grown as an annual, but kale plants are actually biennial, which means their growth cycle lasts two years. The first year kale is planted, it will produce lots of green leaves, and it will continue to produce leaves throughout the winter season in USDA hardiness zones 7 through 10. In its second year, kale will eventually begin to bolt, or go to seed, sending up a flowering stalk that can be eaten or left on the plant to produce seeds that, once they have matured, the gardener can collect and save in order to plant a new crop.
When kale is harvested properly, it works as a cut and come again vegetable that quickly grows back to regenerate its leaves for multiple harvests. For your kale to grow back, harvest the oldest leaves first—those on the outside of the plant at the bottom. Use clean, sterilized garden shears to clip the leaves from the plant along with their stem. As long as you remove the stem along with the leaves and harvest the oldest leaves first, your plant will keep producing more leaves to replace the ones you’ve harvested.
Kale is easy to grow by directly planting seeds outdoors, or by starting seeds indoors and transplanting. It grows well in-ground, in raised beds, or in containers if you don’t have a lot of garden space to work with. Kale is very hardy, and if provided with the proper growing environment, is a very plentiful crop to grow in your vegetable garden.
Fertilize the beds by mixing in several inches of compost or aged-manure prior to planting kale. When planting, use 0.5 cups of an all-purpose 5-10-10 fertilizer for each 10 feet of row. Mix it into the top 3 to 4 inches of soil. Keep your kale growing with side dressing throughout the growing season. Use compost or feed with some type of high nitrogen fertilizer like fish emulsion.
Kale can be planted in the spring for a summer harvest or in the late summer for a fall harvest.
From the day seeds are planted, it takes kale between 70 and 80 days to mature until it’s ready for harvesting. If you count from the date young plants are transplanted into the garden, it takes kale 55 days to be ready to harvest.
To harvest kale so it continues to grow and replace its leaves, use clean, sterilized shears to snip off the oldest leaves first, stem and all. Make sure to take the oldest leaves, which are on the outside of the plant at its base. As long as you remove the stem along with the leaves and harvest the oldest leaves first, your kale plant should continue growing and producing leaves for future harvests.
You can grow kale in in-ground gardens, in raised beds, or in containers. Just place them in a location with full sun and well-drained, fertile soil with a pH of 6.5 to 6.8.
Kale leaves turning bitter is a sign that your plant has begun to bolt, or flower. The leaves of the plant become slightly tough in texture and bitter in taste as the focus of the plant has shifted to producing flowers and has turned its attention away from the leaves. Another culprit that tends to turn garden kale bitter is warm weather, which often leads to bolting. Cool temperatures equals sweet kale leaves. Help promote a cool environment by providing a steady supply of water and mulch around your kale plants to improve the soil temperatures and help boost moisture retention.
If you harvest kale correctly, the plant will continue to grow and produce leaves. Wait until your kale is 8 to 10 inches tall to harvest it. This takes about 55 days after transplanting the kale as small seedlings in the garden, or about 70 to 80 days after sowing seeds. Cut the outer, lower stems with scissors or hand clippers to harvest them. You can also bend and snap them off if desired. If any look damaged or yellow, discard them. Green leaves are ready to be washed and stored or cooked. Leave at least four inner leaves that are still developing on each plant so it continues to produce more leaves throughout the winter as needed. Cut all the stems with hand clippers if you want to harvest the whole plant. Leave about 2 inches of stems intact and your kale might produce another harvest.
Kale can survive in temperatures as low as 10 degrees and is also known for improved sweetness after frost. Kale is a very hardy vegetable which not only tolerates the cold, but it has no problems with common insects like cabbage has.
For more information, consult Rodale’s Garden Problem Solver and/or the following resources:
The Book of Kale: The Easy-to-Grow Superfood 80+ Recipes (Amazon affiliate link)
How to Grow Kale from Seed from NC Cooperative Extension
Kale: A nutrition powerhouse from Alaskan gardens from University of Alaska Fairbanks Cooperative Extension
Please note that links to Amazon from Gardening Channel are affiliate links.
Jan Vessell says
I have a packet of seeds from Johnnys for Kalettes. Can’t find them in grocery stores so I’ll try to grow them myself. I use 4’x8′ raised beds.
john cahill says
im going to try and grow things in my garden again … green veg high in nutrition , and hardy .. kale ! .. and ?? … thank you very much … john
it maybe the dummest question you will ever encountered, but can you use apple cider vinegar as replacement to any soap or chemical spray for apids and other organic plant pest?
Joe Richardson says
I dont grow Kale but I do grow chard and my favourite way of preparing either chard or spinach is to cut the leaves into strips fry in a wok using olive oil with some 2cm squares of bacon then when the bacon is ready sprinkle some parmesan and serve.
tony stiga says
If you like creamed spinach, you’ll love creamed kale………………..
I like my kale chips made with sesame oil. It really ramps up the flavor.
Rosalind Simmons says
I like Kale done as a puree.
Fry onion and garlic. Add chopped up kale and cook gently as is with lid on a heavy saucepan. Season with salt, pepper and nutmeg. Blend in a food processor. Eat like soft mash.
Nonemail of you have mentioned good old fashioned kale greens
My mom cooked kale with chopped onions, a small chunk of ham, diced, and red pepper flakes, and salt to taste. Then you simmer it, stirring occasionally until the color fades a bit
May not be the healthiest way, but it’s the tastiest. Same deal for collards and Swiss chard. Nothing beats a good pot of greens!
Cabbage worms will own your kale plant in my area if you don’t take preventative measures. I cover the leaves with row cover material, allowing slightly reduced sunlight in but no cabbage moths get access to the leaves. The result is I get plenty perfect kale leaves that I’m not sharing with any pests.
Dear Roger: I’m a kale freak. I can’t grow them in my apartment. Will they grow in pots on my balcony? — Patricia Harrison, Wilmington
Dear Patricia: You absolutely can grow fine kale in a pot. Kale grows big and needs a big container. Use at least a 3-gallon pot. Or try a 5-gallon pail, or be creative and go for three plants in an oak half-barrel.
You may sow seeds now or in early spring, late March through April, in your containers on the balcony. They’ll come up in just a few days. In two weeks, they’ll start to have true leaves. That’s the best time to thin the seedlings. Leave the biggest two or three seedlings in each pot. In half-barrels, leave three or more groups of two or three.
Your young kale seedling may be damaged by sudden and extreme cold snaps. So start the kale in small pots that can be easily moved indoors during any sudden dip below 20 degrees Fahrenheit. Move the plants outdoors as soon as nights warm into the mid-20s. Leaving them indoors too long will destroy their cold resistance.
Move strong young plants to larger pots after a few weeks. Despite the large pots, the plants will need daily watering when they reach full size in the heat of spring or summer. You may pick a few young, tender leaves to add flavor to salads all winter, but leave plenty on the plant to produce good greens for boiling with fatback or olive oil.
Late-started kale produces great fall and spring crops with huge leaves and remarkable flavor.
Good potting mix is worth more than its price in increased production of big, sweet leaves. Some fertilizers contain slow-release nutrients that last for several months.
If you grow kale in the ground, you don’t need potting mix, just a good 3- to 4-inch mulch to protect soil moisture in summer and soil temperatures all year.
Kale grows best with plenty of nitrogen. In pots, give plants frequent watering with half-strength soluble high-nitrogen fertilizer, or use coated, slow-release fertilizer once or twice depending on whether it’s a three-month or six-month fertilizer.
In garden soil, mix in a tiny bit of organic fertilizer before planting and side dress with more each month.
Remember to take into account the nitrogen that may be included in your potting mix. You may not need any extra nitrogen for the first few months.
Lots of sun will help your plants be as productive as possible. A northern exposure will produce wimpy plants, but you will still get some pretty tasty greens. Sun-grown kale are very high in vitamins. They have high amounts of vitamin K, and good amounts of vitamins C, A and B6 and the minerals manganese and calcium.
A south-facing patio is ideal.
Start the seeds outdoors. Seeds started indoors this time of year may be damaged by freezing when they are moved outdoors. Seeds started outdoors will generally take care of themselves, except when they are less than a month old.
Freezes down into the mid-20s in winter may burn the leaves somewhat, but a rapid recovery can be expected.
Freezes down to 5 degrees may kill plants to the ground, but they will generally recover vigorously in time and make plenty of leaves to eat. A loose mulch of pine needles 6 inches to a foot thick will help protect the plants.
Dear Roger: I stored some daylily seeds from my garden. I am drying them, and I have a quick question. I looked on the Internet and, of the several pieces I read, the directions said to soak the seeds and refrigerate from three to eight weeks and then plant. One site said to dry the seeds and plant directly in a good potting medium, keep moist, and in the bright sun (for energy).
Which is best? — Joni Martin, Laurinburg
Dear Joni: Thank you for your faith in my advice. I do the following:
• Pick seeds when pods turn brown and begin to crack open. Shell them out in a day or two.
• Let them dry on the porch outdoors for at least two days. Toss out the seeds that have nothing but air in them. And eliminate the squishy ones, too. Give them a light squeeze. If they are not firm, throw them away.
I eliminate the “air seeds” that contain nothing by putting the seeds in a shallow bowl. I blow on the seeds while I turn the bowl and walk around. This is done outdoors, of course. The lighter, empty seeds will blow out of the bowl while the heavy, fertile seeds stay in.
• Put the seeds in plastic, sealable baggies on a humid day, or blow your hot breath into the bag. Insert any labels or tags you want to make before sealing. We use jewelry price tags or small pieces of paper and a Sharpie pen.
• Refrigerate at least four weeks at 41 to 42 degrees. Some seeds will be very dormant. Most will come up without a cool period. Some may sprout in the refrigerator. Most won’t, especially if the parents are types that can go completely dormant in winter.
The eight-week cooling period is better if dormancy is important to you. It will ensure that all viable dormant seeds come up, along with the ones from evergreen parents that need no cool period. After cooling, plant in a good potting mix in seed flats or pots in spring or in a greenhouse anytime. When the seedlings get planted in the ground, we make labels for them using the tags from the baggies. We print labels using a Brother label printer for outdoor labels. We paste the labels onto pieces of cut plastic slats from discarded blinds. These usually last for the four to six years it takes us to evaluate a daylily seedling. We grow about 80,000 to 120,000 new seedlings a year for evaluation.
Since we evaluate our seedlings for many years for multiple qualities, we will have more than 250,000 daylilies in bloom in any given year. That represents three to four years worth of seedlings, plus the thousand or so we may have selected to keep as the best from the 80,000 or so we bloomed in a previous year. Eventually, we get the keepers down to fewer than 100 per year, including the 30 or so that we choose to name.
I say this by way of warning. Many of your daylily seedlings will be so beautiful year after next that you will find it hard to part with them.
One of my customers in Greensboro once told me he had torn out his paved driveway to make more room for his daylilies. So you must learn to be very picky about which ones you keep when you start growing daylilies from seeds. Or you will have more daylilies than you can deal with.
You can plant kale in a container in two ways. You can start the plant from seeds directly in the pot or transplant an already established seedling.
When you direct sow kale seeds in a container, you’ll want to plant many more seeds than the number of plants you’ll end up growing. Plant the seeds about three inches apart and about 1/2 inch deep.
Once the seeds germinate and produce a small seedling, you’ll need to thin the plants out. As soon as the plants have about two sets of leaves, cut down any unhealthy looking ones, at the soil line and discard.
Leave only as many plants as you were hoping to grow in the container. In a smaller container, that should be just one kale plant. In a larger pot, you can safely grow two or three plants.
If you’re getting a late start on growing kale or know that you just want to grow a single plant, starting with a transplant is often easiest.
The video from the Wisconsin Public Gardener shows you how simple it can be to plant a kale seedling in a container. Fill the pot with soil, make a hole in the soil about the size of the transplant’s root ball, then place the seedling in the hole.
Plant the kale as deep as its root ball. There’s no need to cover any part of the stem with soil. Once it’s planted, add water to help it get settled.
Container grown kale might need more attention and care than kale grown in the ground. Containers often dry out more quickly than garden soil, so you will most likely find yourself watering the plant more often.
Water enough that the soil stays moist, but not so much that it’s water logged or has puddles on the surface.
If you used a container mix designed for vegetables, you might not need to fertilize the kale during the growing season. If your kale looks a little worn or starts to develop yellow leaves, you can add a handful of compost to the mix in the pot or water it with a compost tea every few weeks.
Growing kale in a container lets you maximize a limited amount of space in your garden or grow veggies even if you don’t have any in-ground space. You can put the containers on a small balcony, patio or any location that gets enough sunlight.
It’s time to harvest when the leaves are about the size of your hand. Pick them one by one, starting with the lowest, outermost leaves and working toward the center. Always leave a few of the small central leaves attached to encourage growth. In most cases, you’ll be able to harvest from the same plant again in five to seven days.