Growing Kale: How To Get Great Greens Harvests
Grow your own superfood! Growing kale is easy and fun. Learn all about it in our complete guide, along with tips for storage and preservation!
In recent years, it’s gotten a reputation as a superfood. Leaf cabbage, also called kale, is a brassica species that really packs a punch. But growing kale isn’t something a lot of people consider doing.
They should! Vitamin-packed kale (Brassica oleracea) is considered to be among the world’s healthiest foods. Rich in Vitamins A, C, and K, it’s also mineral-rich, packing a good calcium and potassium punch. For a leafy green, it’s protein-rich as well. One cup of kale will give you 2.2 grams of protein.
We’re going to give you the best tips in this guide to growing kale, including information about the various types and a good number of planting tips. By the time we’re done, you’ll be an expert in growing kale.
Good Products At Amazon For Growing Kale:
- Neem Bliss 100% Cold Pressed Neem Oil
- Monterey BT Caterpillar Killer (Bacillus thuringiensis)
- PyGanic Botanical Insecticide (Pyrethrin)
- Garden Safe Snail & Slug Bait
- NaturesGoodGuys Beneficial Nematodes
- Southern Ag Liquid Copper Fungicide
Quick Care Guide
|Common Name(s)||Kale, lacinato kale, dinosaur kale, leaf cabbage, etc.|
|Scientific Name||Brassica oleracea|
|Days to Harvest||45-110 days, depending on the variety|
|Light||Full sun to partial shade|
|Water||1” to 1.5” per week|
|Soil||Well-draining, rich soil, slightly acidic|
|Fertilizer||Balanced 10-10-10 fertilizer or rich compost|
|Pests||Aphids, whiteflies, thrips, cabbage worms, cabbage loopers, etc.|
|Diseases||Clubroot, alternaria leaf spot, anthracnose, etc.|
Recommended Kale Varieties
A member of the cabbage family, kale comes in different varieties. Before we get into teh weeds that are this guide to growing kale, let’s go over those varieties now and explore the variations.
These kale types are considered ruffled or frilled leaf types. These leafy greens form dense, deep curled patterns which look almost like gathered lace.
Often used for ornamentation or plating in cooking, these also work extremely well in salads and soups. Because of their pretty leaf shape, they’re some of the most common plants chosen for growing kale.
- Siberian Dwarf: 50 days. 14″ tall, super-hardy to cold weather and cold temperatures. Ruffled leaves.
- Redbor: 50 days. My favorite kale, a magenta to deep purple frilly variety. Tasty stuff!
- Scarlet: 50 days. Green with purple tinges to full purple, beautifully frilly leaves.
- Dwarf Blue Curled Vates: 55 days. Bluish-green leaves, this kale grows best in cooler spring or fall weather.
- Dwarf Blue Curled Scotch: 56 days. Heirloom early winter kale, great frost resistance. Good flavor due to winter harvest.
- Casper: 60 days. This kale grows snow-white veins and sage-green margins. Unusually beautiful and tasty!
- Prizm: 60 days. Short, tight-ruffled deep-green leaves with almost stemless stalks.
- Winterbor: 60 days. Thick, blue-green leaves, vigorous. Especially good for a winter harvest but this kale grows in spring/fall well too.
- Red Ursa: 65 days. A frilly Red Russian with vivid green leaves and deep red stems/petioles.
- Darkbor: 75 days. Hybrid medium-green kale with a tight curling to the leaves.
Flat Leaf Kale
By contrast, these kale varieties tend towards flatter, easier-to-trim leaves. Some have fringe-like exteriors, giving them an interesting shape. One variety is even described as being like maple leaves.
Flat-leaf kales tend to be more tender than the curly varieties and work well in salads. Try growing kale of flat-leaf varieties for faster harvests too!
- Fizz: 40 days. Quick growth, makes perfect baby greens. Finely-lobed leaves in golden-green.
- Russian Red: 50 days. Oak-like leaves with a red tinge and purplish stems. Tender and mild.
- Bolshoi: 55 days. One of the sweetest kales. Silvery-green leaves, magenta veins and stems.
- Red: 60 days. Flat leaves with cut margins, young plants are green but turn reddish-purple.
- Roulette: 60 days. Slate-green leaves, purple veins/ribs/stems. Flavorful and vigorous.
- Premier: 65 days. Medium-green foliage, with up to 1-foot-long leaves. Big producer!
- Forage Proteor: 70 days. A forage kale for livestock feed with extreme winter hardiness.
- Beira: 80 days. Traditional leaf kale for Portugese kale soup, and is also called sea kale. Can reach 2-foot height.
Lacinato kale or Tuscan kale is commonly referred to as “dinosaur kale” simply because of the size and texture of the leaves. If you want to try growing kale that’s tall with narrow leaves which are deep green and bumpy like dinosaur skin, these are the ones for you.
However, because of its savoyed and long leaf shape, Tuscan kale is extremely easy to trim out stalks. The long leaf shape makes it easy to slice up for salads and use in soups and stews.
- Nero di Toscana: 60 days. Deep, black-green leaves that reach lengths of up to 24″. Italian heirloom.
- Black Magic: 65 days. Toscano-type kale with long, narrow savoyed leaves.
Don’t let the name fool you! Ornamental kales are just as edible as the other kale varieties. Also referred to as “flowering kale”, growing kale that’s ornamental provides vibrant little patches of color in the garden.
Most ornamental varieties have a shorter leaf and a more cabbage-like round head, revealing their close relation to the cabbage. The center of these kale heads tends to provide a bright pop of color in the winter garden.
- Red Chidori: 50 days. A frilly-leaf ornamental kale. Rich purple hue and sweet flavor.
- Crane Red: 110 days. Ornamental kale that’s also available as Crane Pink or Crane White. Beautiful in winter gardens.
- Crane Feather King White: 110 days. Serrated ornamental kale, also available as Crane Feather Queen Red.
- Sunrise: 110 days. Small-headed, leaf-type kale. Green outer leaves fade to creamy white with a delicate pink center.
- Sunset: 110 days. Similar to Sunrise, but in vibrant pink.
- Nagoya Rose: 90 days. Available also as Nagoya Red and Nagoya White, formerly called Emperor. Beautiful ornamental with leaves like flowers.
- Song Bird Pink: Only available as cuttings/plants. Outer deep green leaves, inner pink leaves. Also available as Song Bird Red.
- Glamour Red: Only available as cuttings/plants. Glossy leaves, multiple rings of different leaf colors. Beautiful winter kale.
Planting kale itself is extremely easy, much like growing kale. Just follow the steps below for planting before you dive in to this guide to growing kale!
Depending on where you’re located, early spring through summer is best for planting kale. If you’re in an area where it doesn’t regularly get below 15 degrees Fahrenheit, you can also grow most types throughout the winter.
For these areas, plant kale for winter harvests in the fall so it has time to become established before the chilly weather comes on.
If you’d like to get a jump and grow spring-planted kale, you can plant kale seeds indoors in the latter part of the winter. Use a seedling heat mat to keep the soil warm.
Once the kale seeds emerge, use a grow light to provide ample “sun” until you can harden them off outdoors.
In most cool climates, plant kale in full sun conditions. For locations where there are extremely hot summers, you can plant in partial shade to prevent the leaves from bittering.
Kale grows extremely well in raised bed situations but will also grow just as happily in a standard garden bed.
You can also grow kale in a container. You’ll want pots that are gallon-sized or larger for each plant. I actually prefer larger ones so the roots have plenty of room. Our store has our grow bag line including lined grow bags and unlined grow bags, and we also stock Air Pots which are equally perfect for container-grown kale. To save space, consider a 5-tiered or 7-tiered GreenStalk!
As this plant can last for more than one year, you may want to take into consideration how large you want it to get. Older kale can get tall, and you may need to take that into consideration when planning for growing kale in general.
Naturally, kale is biennial, meaning that it can take up to two years to complete its flowering cycle and then die off. Most people grow crops of kale as an annual.
It’s a gorgeous ornamental, even if you don’t want to eat kale! Some varieties, like Redbor, produce stunning, ruffled purple or reddish leaves that can create a bright counterpoint for other plants.
Begin growing kale by loosening the soil and adding any fertilizer you wish to add.
Once your soil is prepared, plant kale seeds 1/4″ to 1/2″ deep. Once they’ve come up, wait 2 weeks and then thin out the kale seedlings. Ideally, your kale plants should be about 10″ apart, but anywhere from 8″ to 12″ is fine.
For transplanting young kale plants, see the section below, as planting kale seedlings is slightly different.
Caring For Kale Plants
For the most part, a kale plant will take care of itself, provided it’s got what it needs. When growing kale, make sure you have the best conditions you can provide. Keep reading to learn what conditions are optimal.
Sun and Temperature
In most moderate climates, growing kale in full sun conditions is just fine. The more light you can provide, the better. Same with cooler climates and times when the weather keeps the soil cool.
However, if you live in the desert, aim for partial sun conditions. Kale will benefit from some afternoon shade during the worst heat of the day.
Kale requires at least 6 hours of sun per day even in partial shade for best growth.
Kale seeds will germinate at as low as 40 F, but they sprout more quickly at soil temperatures in the 60s.
The plant itself loves temperatures between 65 and 75 degrees and will thrive at that range. However, it can tolerate weather extremes very well.
In the heat, leaves will become more bitter. In light frost conditions, the leaves become sweeter and can pick up an almost nutty flavor.
Full freeze conditions and consistent cold weather require some form of protection, such as a cold frame. Established kale plants will tolerate extreme heat but will require extra water and can benefit from mulching to slow evaporation.
You can grow kale as a biennial, as it will often grow year-round. Trying to provide the best temperature range possible each season will make for happier, healthier kale plants.
Water and Humidity
Speaking of water, kale likes even, consistent moisture. An inch to an inch and a half of water per week is sufficient to keep your kale pleasantly happy.
However, you are going to need to ensure that your soil drains well. Kale typically doesn’t like to have wet feet. If your soil’s too soggy, it promotes fungal diseases like root rots, which will kill off an otherwise-healthy plant.
Well-drained soil is best for kale, as I just said. However, it’s a heavy feeder. Be sure to mix in plenty of compost prior to planting, along with a slow-release fertilizer. This provides ample nutrition for your kale plants.
If you have sandier soil, consider working in some organic material. Peat moss can provide moisture retention while still allowing the excess water to drain easily. Most composts work similarly as well.
Clay soils need to be repaired to prevent water buildup on the soil surface. While you can grow kale in a clay soil, it’s more susceptible to problems, and may not get as large as it might in other soil types.
Kale prefers a pH range of 5.5-6.5. You can use a neutral soil for kale, but it tends to be a bit happier if the soil is lightly acidic. Pine needle mulches work extremely well for kale as a result.
Fertilizing Kale Plants
If you’ve prepared your soil properly, a single feeding of a slow-release fertilizer once you’ve harvested the leaves once is all that’s required for annual kale. Aim for a balanced fertilizer like a 10-10-10 range.
If that’s not available, opt for higher nitrogen to promote leaf growth.
Granulated fertilizers should be broadcast over the soil’s surface, but avoid touching the side of the plant to prevent fertilizer burn.
Liquid fertilizers are usually diluted and are safe on the plant itself. Kale is especially fond of compost tea and fish emulsions, so these are great choices.
A high-quality compost used as a top dressing will generally provide all of the nutrition needs for your plant as well.
For those growing kale as a biennial, you will want to fertilize once per season to ensure it has sufficient nutrition. It will continue to produce leaves as long as it’s fed right!
For pruning tips, see the “harvesting kale” section below. You shouldn’t have to prune it except during harvest time!
I recommend removing bug-eaten leaves or those which are yellowing, browning, or withering, as they might be diseased. Dispose of those appropriately.
As the plant ages, the lower leaves become inedible first. They will yellow and drop off on their own. Remove them to the compost pile, so they don’t encourage pests to take up residence.
If you’re growing kale that’s ornamental, you can also remove outer leaves to try to brighten up the bunch. Simply snip them off close to the stem as necessary.
Kale Plant Propagation
Kale is most often propagated by seed, as mentioned above. You can also start growing kale from cuttings.
For cuttings, find an extremely healthy side stem with multiple leaves, and cut it at the main stem of the plant. Trim off the lower side leaves, leaving only the top leaf.
Once your side leaves are removed, examine what’s left. If it’s a large leaf, cut off the top half of the leaf, leaving only the bottom half attached to the stem. This reduces the size of the leaf that the stressed plant will need to care for.
Cut the base of the stem at a 45-degree angle just below one of the leaf nodes, and place it into a pot of prepared, well-draining, and damp potting soil. Mist the soil regularly to keep it moist but not wet.
It should develop roots within 3 weeks.
You can dip the stem into rooting hormone before planting it, but this is purely an optional step. Some reports indicate that rooting is quicker and the plant healthier as a result.
You should be able to transplant your rooted cutting into the garden in about three months after hardening it off to the outside weather.
Planting a young kale plant is quite easy. Prepare your soil, then dig a hole that is large enough to fit all of the soil with the plant to be transplanted.
Carefully remove your kale seedling from its pot. Examine the bottom to make sure the roots are not wrapping around the soil. If they are, gently massage the root and soil mass to loosen it up.
Set your plant into the hole and cover it to just barely above where it had been planted before. Water it in well.
Did you know that you can grow kale extremely well as a microgreen? As the stem is edible along with its leaves, it makes for a tasty treat!
You can read our article on how to grow kale microgreens for a wealth of information on this topic. In that piece, I’ll take you through the entire process. Everything from seeding the tray, caring for the sprouts, and harvesting them is covered.
When you’re planting, don’t forget to include kale companion plants too!
Harvesting and Storing Kale
While this process may seem a bit tricky, I’ll show you how to do it quick and easy!
But before we begin, here’s our video on how to harvest kale.
How To Harvest Kale
The trick to know about harvesting kale is when it’s best to harvest.
In the heat of the summer, larger leaves can become more bitter, so it’s important to pick them when they’re still young and new rather than grow kale to monstrous sizes. This is also a great season to harvest kale microgreens.
Early summer and fall harvested kale tends to be less bitter. When you grow kale in winter, it is surprisingly sweet, as long as it doesn’t endure frost conditions that can harm the leaves.
If you are trying to harvest kale for young leaves, you can begin removing the lowest leaves on the plant once it’s 4″ in height. Harvest full-grown leaves once the plant is 10″-12″ in height.
Allow the top clusters of leaves to remain intact for future growth. Usually, a typical harvest is just a handful of leaves.
In the peak heat of the summer, do a hard cutback of your kale to encourage new growth. This helps eliminate those bitter leaves. Remove all but the top four or five leaves from the kale plant, leaving a tall stalk.
Allow the leaves to grow back on their own. You should have new leaf growth within two weeks, allowing you to harvest kale in late summer.
Kale can be stored in the refrigerator for up to a week without any problem at all as long as you know how to protect it.
Do not wash your freshly-harvested kale unless you make sure it’s completely dry before storing.
Instead, bring your kale inside and wrap the bundle in paper towels. Place it in a zip-top bag in the coldest part of your refrigerator. Be sure to remove as much air as possible from the bag before storing.
If you have a flat-leaf kale variety, it’s even easier to protect your leaves. Lay out a strip of paper towel, and place your leaves on top of it. Top with another strip of paper towel.
Then, starting at one end, gently roll it up into a bundle that will fit into your zip-top bag. Remove excess air from your bag and place in the coldest part of your refrigerator.
If you’d like to prepare kale for future salad use, you can remove the stems and slice it into ribbons. Place it between paper towels in a zip-top bag with excess air removed.
Don’t waste the stems, though! You can cook the stems on their own as a nutritious green vegetable.
Prepare a large pot of boiling, salted water, as well as a bowl of ice water. Remove the stems from your kale and drop the leaves into the pot until they brighten in color. This should take 1-2 minutes.
Then, remove the leaves. Place them in a colander and shake out any excess hot water, then submerge the leaves in ice water to stop the cooking. Once fully chilled, dry your leaves in a salad spinner or pat them thoroughly dry.
Place your dried kale leaves onto a baking sheet in the freezer until the leaves are frozen solid. This should take a couple of hours. Once they’re completely frozen, transfer the leaves to a freezer bag with excess air removed.
These can be added to soups or stews while still frozen. They’ll thaw and cook in the soup, and they’re easy to chop down to a reasonable size while frozen. You can also add them directly to smoothie mixes.
Kale can be canned. This requires a pressure canner, as it’s a low-acid food. Check the manual that comes with your pressure canner for a recipe, or look for a canning recipe book to ensure you have a safe method.
It can be dehydrated too! Have you seen kale chips at the market? They charge a small fortune for them, but you can make them at home and eat kale in its most fun form.
A dehydrator with heat will quick-dry kale in under 5 hours, whereas an unheated or low-heat dehydrator may take as long as 8 hours.
If you don’t have a dehydrator, you can always use your oven to make kale chips. Once made, either store them in a sealed, airtight container with a desiccant packet or a zip-top bag with all the air removed and a desiccant packet.
Kale can also be freeze-dried. While few of us have an expensive freeze-drier, those who do will find that you can freeze-dry the leaves to use later in soups, stews, or as kale chips on their own.
If it’s dehydrated or freeze-dried without any added flavoring, you can powder the dried leaves and store them in a mason jar with a desiccant packet. This kale powder makes a great addition to smoothies.
Troubleshooting Kale Problems
From reading this guide to growing kale, you may know it doesn’t have many problems. When it does, they’re typically pest or disease-related. Let’s go over some of those now and how to handle them.
Aphids, especially cabbage aphids and turnip aphids, find kale delicious. They also carry a wide number of plant diseases, and can cause major plant wilting.
Beating all three is easy, as regular spraying of neem oil repels them. It also kills off existing infestations.
Thankfully, there’s one solution for all of these caterpillars: bacillus thuringiensis var. kurstaki. A BT spray is usually the simplest solution.
The root knot nematode can be another problem. They chew into root structures under the soil’s surface, causing major damage.
With these, you’ll want to fight back by applying beneficial nematodes as plant defenders. They take out many pests, including root-knot nematodes, fungus gnats, root maggots, wireworms, cucumber beetles, and more.
While beneficial nematodes can help wipe out root maggots, they don’t work against flea beetles. In these situations, I recommend a naturally-derived pyrethrin spray that can demolish both pests.
Finally, snails and slugs will leave slimy trails along your kale leaves and chew leaves into oblivion.
Use a snail and slug bait and sprinkle it around the outskirts of your garden. They’ll find it on their way to eat your kale, eat the bait instead, and die.
Clubroot is a common fungal disease among cole crops. It causes the roots of your kale to become clubbed and misshapen, plus prevents them from easily taking up water or nutrition.
The most difficult thing about clubroot is that most common fungicides won’t fix the problem. It’s spread by tiny fungal spores that can live in your soil for up to 20 years.
Your only real solution is to avoid planting susceptible crops in that location. Solarizing the soil to sterilize it may also help kill off the spores, but isn’t always successful.
Alternaria leaf spot is another problem. This fungal disease causes water-soaked brown or black spots on kale leaves, sometimes with a yellowish ring around the spots.
While there’s no cure for alternaria, there are prevention measures. Using a product with bacillus subtilis in it will help build up plant resistance. Neem oil can help protect the leaves against fungal spores.
Another fungal disease that strikes kale is anthracnose. This causes greyish to straw-colored spotting on leaves and can also spot stems. Untreated, it weakens the plant and can lead to other diseases such as bacterial root rot.
Treatment for anthracnose involves spraying the plant thoroughly with a copper-based fungicide. Keeping the soil slightly more dry can help prevent further outbreaks.
The soil fungus Rhizoctonia can cause a number of problems for kale. Young seedlings can fall victim to damping-off, where they rot right at the soil line in moist soil. When you grow kale that’s older, it can become susceptible to wirestem, which can stunt the plant’s growth. It also causes bottom rot.
Avoiding rhizoctonia is usually as simple as being sure to rotate crops. Don’t plant new kale crops in the same location year after year. The fungus can live in the soil for up to three years, so practicing good crop rotation can allow it to die off.
Black leg, or phoma stem canker as it’s alternately called, is a newly-emerging fungal disease in the Pacific Northwest. It causes stunted growth and girdling of the stem, and can lead to reduced yields or plant death.
This disease currently has no established treatment other than to stop the spread of the fungal spores. Some chemical fungicides have proven to assist slightly with prevention.
Blackleg appears in areas which are prone to humid or wet conditions, and can be spread by soil, infected tools, or on the seed itself.
The only things that have offered hope so far are hot water seed treatment prior to planting and the prevention of the conditions for the spores to develop.
Avoid planting brassicas — or other members of the cabbage family — in an area where black leg has developed for at least four years, and consider solarizing the soil to try to kill off fungal growth. Destroy infected kale plants before they can produce more spores.
Downy mildew rounds out the list of fungal diseases that can hit kale. This causes yellow to white patches on the top of leaves, and underneath the leaf a grey fungal mass develops.
To avoid downy mildew, improve airflow around your kale plants and try to avoid getting them wet. It develops quickly in humid or moist conditions. Copper fungicide will kill it, and neem oil is also effective.
Finally, there’s black rot, the only common bacterial infection of kale. All cruciferous crops are susceptible in varying levels to black rot. This causes yellowing on the edge of the leaf, which gradually spreads to a V shape. It can destroy the entire plant if it gets into the plant’s veins.
While copper fungicides can help with black rot, what’s truly most effective is prevention. Ensure there’s good airflow around your kale plants, and try to reduce humid conditions as much as possible. Rotate crops annually and wait at least two years before growing kale or other crucifers in that spot.
Frequently Asked Questions
Q: Does kale regrow after cutting?
A: If you harvest kale at a rate of less than 1/3 of your kale plants at a time, focusing on outer leaves, they will continue to grow kale leaves from their center.
Q: How long does it take to grow kale?
A: Most varieties take 65 to 75 days to grow to mature kale plants. However, in the scope of all cultivars, there’s a range of 45 to 110 days.
Q: What should not be planted by kale?
A: Avoid planting kale next to too many other brassicas. Keep vegetables like broccoli, cauliflower, cabbage, Brussels sprouts, bok choy, and collards away from kale.
Q: Does kale come back every year?
A: Yes! As long as you leave your kale plants mostly intact, they’ll be biennial to perennial, depending on your region. Warmer regions can sometimes create conditions where kale can be a perennial.
Q: Should you let kale flower?
A: If you would like to continue harvesting from the plant, pinch off flowers as they appear. Otherwise, you can let it flower to attract pollinators and collect the resulting seeds.
Q: What month do you plant kale?
A: Regardless of the month, plant kale seeds 3 weeks before or after frost in spring or fall. Both fall and spring-planted kale are possible!
Q: Does kale need a lot of water?
A: Not necessarily. Give it about 1 to 1.5 inches of water per week.
Q: Do tomatoes and kale grow well together?
A: Aside from other cabbage family members, tomatoes are another bad kale companion. That’s because both plants compete for the same nutrients.