Is there any vegetable that offers a better return on investment than kale? Not only is this stately green extremely nutritious and easy to use in a wide variety of dishes, it is also hardy, extremely cold tolerant and takes up almost no space in your garden bed. Frankly, that isn’t a good reason why a motivated gardener shouldn’t start growing kale.
As a member of the Brassica family, kale is closely related to broccoli, cauliflower, and cabbage. However, you get more food from kale plants because the leaves are what is eaten, not the flower buds or cabbage. This means that kale is an extremely efficient crop for the space-conscious gardener. Once your plants are established, you’ll be in shock at just how easy it is to grow kale.
- When & Where You Should Grow
- Understanding Seed Germination
- Moving Outdoors
- Direct Sowing
- Watering & Mulching
- Companion Planting
- Common Pests & Diseases
- Harvesting & Storing
- Saving Seeds
- Best Variety for You
Start Growing Kale
Kale is a versatile plant that can grow in a wide variety of conditions. From traditional garden beds to raised beds or pots, and even in flower gardens as an ornamental edible. The range of colors in the leaves of kale plants can make them a stunning display crop.
When and Where Should You Grow Kale?
Kale can be grown well in just about every climate zone, and colder climates can even overwinter their crop in order to get an impressively early spring harvest. Though it tends to do best in full sun, you can grow kale in partial shade in especially hot climates. Too much sun exposure often leaves kale leaves tough and bitter.
Understanding Seed Germination for Kale
Kale seeds are surprisingly hardy and can germinate in cool soil, though you’re most likely to have success if you plant them in temperatures above 70 degrees F. Row cover can be used to warm up the soil and keep seeds above the 45 degrees needed for germination.
When stored properly, your kale seeds should last up to five years.
Starting Seeds Indoors
For an early spring planting, you can start growing kale indoors four to six weeks before the last frost date. To start your kale seeds, sow seeds in small pots filled with planting soil and composts. Plant each seed at least half an inch deep and keep the soil around the seeds consistently moist until the seeds start to germinate.
Preparing a Kale Bed
Kale beds are most effective when they are in full sun and filled with organic compost. Try to keep your pH levels between 6.0-7.0 for best success. For a more robust harvest, grow a legume cover crop in your kale bed before tilling over the soil to plant your kale.
You can bring your kale plants outside one to two weeks before the last frost date in your area, so long as they have formed three to four “true” leaves. Be sure to harden the plants off first by taking them outdoors for varying amounts of time so that they can get used to outside temperatures.
Space your seedlings about 12 to 15 inches apart in rows that are 18 to 24 inches apart, allowing them the space they need to get big and lush. So long as your plants have some protection from chilly winds, they should be able to establish themselves quickly and grow fast.
Growing Kale in Containers
Because of its minimal space concerns, kale can be easily grown in containers. Make sure you chose a pot that has at least six square inches for the plant to grow in, and that you can move it from sunny to shady places as the weather changes. If you plan to keep your kale plants indoors, be sure to position them near a sunny window or under grow lights.
Kale seeds can be directly sowed early in the season, usually about a month before the last frost date or as soon as the ground thaws enough to be worked. Plant each seed a quarter inch deep and spaced six to eight inches apart. When the plants are about four inches tall you can thin them to about 18 inches apart. Be sure to keep the small plants as they are delicious when mixed in salads!
For a late fall harvest, you can plant your kale seeds six to eight weeks before the first fall frost date.
Watering and Mulching Requirements
Kale tends to be a thirsty plant and appreciates at least an inch of water a week, especially during the hottest part of the growing season. Once cooler weather hits you can limit your watering to only when the leaves begin to droop.
It’s a smart idea to keep your plants well fertilized throughout the growing season. Monthly injections of fish emulsion or compost tea can go a long ways towards healthy leaf growth.
You can keep your kale leaves clean and hydrated by mulching heavily under each plant. This prevents rainwater from splashing dirt onto the leaves and also allows the soil to retain moisture longer. A biodegradable mulch like grass clippings or leaf litter is beneficial.
Companion Planting and Rotation Considerations
Because kale is a brassica, you should avoid planting it where other brassicas have been planted recently to prevent the spread of disease. Beyond that, just about any garden plant does well when planted next to kale, with the exception of beans, grapes, and strawberries.
Common Pests and Diseases for Kale
Pests and diseases tend to leave kale plants alone, but there are a few that have the potential to wreak havoc on your plants. A common pest is the cabbage worm, which is the larval stage of the white cabbage butterfly. These flying insects lay eggs on your kale plants that soon hatch into the cabbage worms that so happily munch on your plants and create large holes in the leaves. The best way to control cabbage worms is to pick them off your leaves and squish them, or use an organic pest control spray to get them back under control. A floating row cover can stop the cabbage butterflies from landing on your kale, preventing them from laying their eggs.
Harvesting and Storing Kale
Kale leaves can be harvested after the plants are at least one month old, or when the leaves have reached the size you desire. A deep rich color and firm texture is a sure sign that the leaves are ready for harvest. Smaller leaves make great salads while the bigger, darker ones are excellent for cooking and stir-fries. To harvest leaves, simply push on the kale stalk until they snap off. Harvesting kale leaves throughout the season helps to stimulate the plant to continue to produce new growth.
Don’t be afraid to continue harvesting your kale after the first frost of the season hits. In fact, a few frosts actually cause the kale plant’s natural sugars to concentrate in the kale leaves, making them sweeter!
Kale leaves can usually last about two weeks in the refrigerator, but you can also store the leaves through blanching and freezing for winter cooking, or dehydrating for some tasty kale chips.
Saving Kale Seeds
If you want to harvest seeds from the kale plants you need to be sure to keep the species isolated from any other kale varieties that it might pollinate with. Because kale is a biennial, it will produce yellow flowers during its second year of growth. Allow these flowers to turn into elongated seed pods and let them dry out on the plant. Gather these dried seed pods in a bag and let them dry indoors for a week before shattering the pods and collecting the largest seeds for planting. Store these seeds in a cool place and they should last for four to five years.
Choosing the Best Kale Seeds for Your Conditions
There is a wide variety of kale varieties that can be grown, and all of them have different advantages for growing them. A brief summary of some of the most popular kale varieties is below.
- Red Russian: these leaves have light purple stalks and veins surrounded by a grayish-green tint. These leaves are exceptionally tender when harvested small and are delicious when used in raw salads.
- Lacinato: often called “dinosaur kale” this variety has dark green leaves and a bumpy texture. It is one of the hardiest varieties and can survive some of the harshest winter conditions. The leaves get tough as they get old, so harvest them young for the best taste.
- Winterbor: this curly kale variety has dark green leaves with ruffled leaves. They are ideal for making kale chips.
Additional Growing Tips for Organic Kale
You should be able to grow your kale crop without too much effort, but the additional tips here should help you find success.
- Early spring kale tends to attract tons of insects by the time summer hits, so many gardeners find it best to pull them out for compost. By July or August, they replant new, young kale transplants to get a robust fall crop.
- If you plan to use kale regularly throughout the summer, be sure to plant at least three to four plants available per household member.