How to Grow Kale From Seed: Planting, Care & Harvesting

Kale is one of the easiest cool-season vegetables to grow from seed, and its cold tolerance makes it especially valuable in the fall garden. With the right planting timing, you can enjoy tender kale leaves in spring, fall, and even through winter in many climates.

For spring planting, start kale seeds indoors 6 to 8 weeks before your last spring frost date. You can also direct sow kale seeds outdoors about 4 to 6 weeks before the last frost, as long as the soil can be worked.

For a fall harvest, sow kale seeds about 6 to 8 weeks before your first expected fall frost date. 

Not sure when to plant kale in your area? Use our Planting Planner to find recommended planting dates based on your local frost dates.

The choice to direct sow or start seeds indoors will hinge on how quickly temperatures rise above 75ºF and when you want to harvest kale. 

If spring temperatures move quickly from 60º to 85º and up, you may find growing kale in the fall and winter will give you a longer harvest.

Kale seeds can be sown directly in the garden. Prepare a well-drained planting bed and sow seeds about 1/4 inch deep. Space seeds about 12 inches apart. 

Keep the soil consistently moist while seeds are germinating. Some varieties will sprout within 5 days, while others may take up to 21 days. Check your seed packet for variety specifics. 

Once seedlings emerge, thin them so the plants have enough room to reach their mature size.

Kale grows best in full sun but can tolerate partial shade. In warm climates, afternoon shade can help keep plants cooler and may reduce bolting.

Rich, loamy soil is best for growing kale. We typically add a few inches of compost before planting kale in our garden. 

Keep kale evenly watered, especially while plants are becoming established. Consistent moisture encourages tender leaf growth and helps prevent plants from becoming stressed. You can add a layer of mulch to help retain moisture.

Kale plants are typically spaced 12-18 inches apart. This allows room for airflow and growth. 

When the kale plants are about 5 inches tall, you can add additional fertilizer and side-dress with compost. 

Kale is a member of the Brassicaceae family, so you may encounter some common pests.

Cabbage worms and loopers. Inspect the undersides of leaves and handpick caterpillars. Row covers can also keep moths from laying eggs. 

Aphids. Check for aphids on new growth and leaf undersides. Use pesticide-free options to control aphids. 

Flea Beetles. Row covers, trap crops, and other natural methods can help control flea beetles. 

Read our blog on Dealing with Pests and Diseases in the Garden for other pest and disease remedies. 

Kale is a cool-season crop, and hot weather can cause plants to bolt, meaning they send up a tall flower stalk and begin producing seeds. Once kale bolts, the leaves can become tougher and more bitter. The plant will also stop producing new leaves.

The best way to prevent premature bolting is to grow kale during cool weather. Plant kale in early spring or late summer for a fall harvest, and keep the soil consistently moist during warm weather. In hot climates, afternoon shade can help keep plants cooler.

If your kale produces a flower stalk before you've had much of a harvest, the problem may be planting at the wrong time for your climate. Try planting earlier in the spring or later in summer so the plants mature during cooler weather.

Once a kale plant has bolted, you can let the plant flower and produce seeds if you want to save seed or provide flowers for beneficial insects.

Fall is one of the best times to grow kale. Cooler temperatures mean less plant stress for healthy growth, and kale can tolerate light frosts. In many areas, kale can provide fresh leaves well into winter. 

Kale is one of the most cold-hardy garden vegetables. Established plants can tolerate frost and freezing temperatures, although new growth slows down as temperatures fall. You can extend your harvest window by using row covers. These can increase temperatures around the plants by a few degrees.

Cold weather can actually improve the flavor of kale, making the leaves sweeter.

Typically, kale will survive in the winter until temperatures drop below 20ºF. For tips on overwintering your vegetable garden, read our blog.

Kale can be grown in pots that are about 12 inches deep. Keeping containers moist and well-fertilized is vital. We cover specifics on container gardening in our Planter’s Library.

Dwarf Siberian Improved Kale is an excellent variety for small spaces and containers. 

Kale can also be grown in hydroponic systems. The picture above shows kale in our indoor grow station.

You can begin harvesting kale once the leaves are large enough to eat. For tender, flavorful greens, start picking when the outer leaves are 5 to 6 inches long. Younger leaves are generally more tender, while older leaves can become tougher. 

Kale can continue producing new leaves throughout the cool growing season as long as temperatures aren't too hot or too cold. In many climates, a single plant can provide multiple harvests.

Kale plants grow new leaves from the center of the plant. To keep the plant growing and producing, harvest the larger outer leaves first, leaving the smaller leaves in the center undisturbed.

Pick a few leaves at a time rather than removing all the leaves at once. Use a knife or scissors to ensure a clean cut without pulling or damaging the rest of the plant. 

Continue harvesting the outer leaves as they reach a usable size. This cut-and-come-again approach can keep kale producing new leaves for weeks or even months when growing conditions remain favorable.

Once leaves are picked, don’t wash them until you are ready to eat them, as they will spoil faster when wet. Kale keeps fresh for about 5 days when stored in a bag or container in the refrigerator.

Harvested kale can be used in a variety of dishes. 

Raw kale can be blended into green smoothies and pressed into fresh juice. 

Chopped up, kale adds crunch and flavor to salads. Try adding grapes, oranges, or cranberries for a little sweetness. 

You can rub the Kale leaves with oil and roast them in the oven for kale chips. Even some of my picky eaters have enjoyed kale this way. 

Kale also makes a beautiful and healthy addition to soups and stews.

It depends on the variety, but kale seeds can germinate in 5 to 10 days. From there, kale takes about 30 days to produce young leaves. For larger, mature leaves, expect roughly 50 to 70 days from planting. 

Kale is an incredibly healthy green. An excellent source of Vitamins A, C, and K, kale is also high in fiber, manganese, copper, calcium, and potassium. So if you want to continue your New Year’s health goals, kale will keep you on the right track. And for an additional nutritional boost, try kale microgreens. They grow quickly indoors.

Kale can be grown year-round in many growing zones. Kale is very cold hardy and can grow in temperatures as low as 20ºF. It is less tolerant of heat and can bolt and go to seed. However, growing kale indoors is one way to grow it year-round. Hydroponics is an easy way to grow kale and other leafy greens. Kale microgreens are another way to enjoy the health benefits of kale in any location.

Kale does well in hydroponic gardens. We recommend Dwarf Siberian Kale for hydroponic growing. 

As long as you leave the inner core of the plant, kale will continue to grow after cutting the outer leaves.