Often hailed as a superfood, kale is one of the most nutritious vegetables, and it’s also incredibly easy to grow in your garden. In this article, you’ll discover how to grow kale and enjoy a season-long harvest of healthy and delicious kale leaves.
Both kale and cabbage go by the botanical name Brassica oleracea, and the two crops are very closely related.
Kale is in the acephala group of the Brassica family, meaning that it doesn’t form a central head like cabbage does. Kale typically gets associated with other cooking greens like collards and Swiss chard.
Kale has a strong, earthy, and mildly bitter taste. Young, tender leaves have a mellower flavor and a more tender texture.
Kale leaves are an excellent addition to fresh salads and are also enjoyable when cooked in soups and stir fries. If you’re looking to add some new veggies to your garden, why not try growing kale this season?
Best Tips for Growing Kale
Kale is a cool season crop, which means that it grows best when temperatures are between 65-75℉.
Most varieties of kale can endure temperatures as low as 20℉ but do not tolerate hot weather very well. Many growers report kale leaves developing a sweeter taste after a light frost.
Kale plants are biennial, meaning that they develop leaves and roots in their first growing season and produce flowers and seeds in the second year.
However, since it tends to turn tough and bitter when temperatures exceed 80℉ for an extended period, kale is usually cultivated as an annual crop.
In most climates, it’s possible to grow kale in the spring and fall. In areas with mild winter, the plants continue producing edible leaves throughout the winter.
Over freezing winters, the plants go dormant, but the root system often stays alive and regrows the following spring.
Plant kale in a location with well-draining soil that’s rich in organic matter. Kale thrives in full sun to partial shade, needing at least five or six hours of direct sunlight each day. Keep the soil continually moist but never soggy.
Provide your kale plants with about one or two inches of water per week, depending on the weather. Applying an ample layer of mulch around your garden beds helps retain soil moisture and keep weed growth to a minimum.
How Long Does Kale Take to Grow?
You may be wondering, “How long does kale take to grow?” Kale is one of the fastest-growing veggies and is ready to harvest in as little as 30-40 days from transplanting. If you’re starting kale from seeds, expect to wait about 55-75 days before harvesting.
There are numerous varieties of kale to choose from, from purple to green leaves and curly kale. There are a few essential factors to keep in mind when selecting which types of kale to grow.
These include your area’s weather patterns, how many days it takes to reach maturity, and what your intended culinary uses are. Here are a few of the top kale varieties for home gardeners.
Growing Kale from Seeds
Plant kale seeds in late winter or early spring so that the seedlings are ready to transplant outdoors about three or four weeks before the average last frost date for your area.
If you don’t live in a place that gets freezing winters, plant kale seeds in your veggie garden anytime the soil is consistently warmer than 45℉. In regions with mild weather, plant a second kale crop in late summer for a fall harvest.
Fill a seedling tray, peat pots, or an egg carton with a nutrient-rich potting mix. Plant kale seeds a quarter-inch deep and lightly cover them with potting soil. Use a clean spray bottle to softly mist the soil until it’s fully saturated.
It’s beneficial to protect your tray with a humidity dome or sheet of plastic wrap to retain soil moisture.
Kale seeds germinate best with soil temperatures between 65-70℉. Germination typically takes between five and eight days under optimal conditions. Keep the soil consistently watered as needed.
Once the kale seedlings begin sprouting, move the tray to a sunny windowsill where they receive six or more hours of bright light each day. If you don’t have a sunny location, use grow lights to prevent the seedlings from becoming elongated or “leggy.”
Like other plants in the cabbage family, kale grows best in cool weather, with optimal temperatures between 60-75℉. Transplant kale seedlings outdoors several weeks before your average last frost date.
They can withstand a light frost but require protection with row cover if the weather gets colder than 20℉. Spacing between plants should be approximately 12 inches.
How to Grow Kale in Pots
If you don’t have a garden plot or raised beds, don’t worry. Growing veggies in pots is easy. Kale is an ideal candidate for container gardening, as well. Growing kale in pots allows you to keep them on your deck, patio, porch, or even indoors.
Container-grown plants require a bit more care than those planted in the ground. Pots dry out faster and also require more frequent fertilization.
In general, water your pots when the top inch of soil is completely dry and fertilize the plants every three to four weeks throughout the growing season.
When the weather gets cold in late fall, move your kale pots next to the wall of your house if possible. The extra heat keeps them growing longer than they would when planted in the ground.
Best Soil for Kale Plants
Kale grows best in cool, moist soil that’s rich in organic matter. The ideal soil pH is slightly acidic, between 6.5 and 6.8, to inhibit clubroot, a common plant disease caused by a soil-borne fungus.
Ensure that the soil drains well, as the plants may develop problems with fungal infection and rot if the soil gets too soggy.
If you’re growing kale in containers, choose a potting soil mix with added perlite for drainage and peat moss or coconut coir to retain soil moisture. Alternatively, try making your own potting mix using this easy recipe.
Blend the ingredients in a large bucket with a lid using a hand rake or trowel. It’s best to use all of your handmade potting mixture at once. If that’s not possible, store it in a cool, dry place in a sealed container.
Choosing the Right Fertilizer
For best results, add organic fertilizer or compost to the soil when planting kale seeds or transplanting seedlings. Measure the fertilizer according to the instructions on the product package, and mix it into the top three or four inches of soil.
There are three essential macronutrients in plant fertilizer: nitrogen (N), phosphorus (P), and potassium (K). Nitrogen boosts leafy growth, phosphorus promotes healthy root systems, and potassium supports fruiting and flowering processes.
When growing leafy greens like cabbage, kale, lettuce, or spinach, choose a high-nitrogen fertilizer.
Throughout the growing season, fertilize your kale plants every four to six weeks through late summer or early fall. Scatter used coffee grounds around the base of the plants to add extra nitrogen to the soil and make it slightly more acidic.
Harvesting and Storing Kale
Kale leaves taste sweetest when picked in the early fall after a light frost. However, they’re edible and delicious in late spring and early summer, as well. The leaves begin turning tough and bitter when temperatures are consistently 80℉ or higher.
For baby kale greens, harvest young, tender leaves within 30 days of transplanting. For larger, more mature leaves, wait 50-70 days before harvesting. Use a clean, sharp knife or clippers to trim your kale leaves to avoid accidental damage to the main stem.
To enjoy a continuous harvest, cut the lowest leaves from the plant as needed, rather than taking them from the center of the plant. Avoid harvesting more than half of the leaves at once to allow the plant to photosynthesize and create enough energy to keep growing.
Store kale in the refrigerator with the stems submerged in a glass of water or wrapped in damp paper towels. Once harvested, kale leaves stay fresh for up to two weeks.
It’s also possible to freeze kale. Unblanched, frozen kale lasts about four to six weeks. With blanching, it keeps for up to a year. However, it’s best to use frozen kale as soon as possible for the best possible flavor and texture.
Common Pest and Disease Problems for Kale
Although kale is generally one of the most low-maintenance veggies in the garden, there are a few pest and disease issues to keep an eye out for.
Plants tend to be more vulnerable to attacks from insects and pathogens when they’re stressed. Ensure that they stay healthy by providing adequate amounts of sunlight, water, and fertilizer.
Aphids, cabbage loopers, cabbage worms, cutworms, and flea beetles are some of the most common insects that feed on kale plants. Their feeding damages the plants’ leaves, stems, and roots and may even kill young seedlings.
If you find aphids on kale, or any other pests, spray all parts of the plant with an organic insecticide like neem oil or insecticidal soap to kill aphids and flea beetles on contact. Diatomaceous earth kills cabbage loopers, cabbage worms, and cutworms, which are the larvae of some moths and butterflies.
Another option is to use an organic biological pesticide like Bacillus thuringiensis, which is a species of bacteria naturally found in soil. It secretes proteins that are toxic to most types of caterpillars, including cabbage worms, cabbage loopers, and cutworms.
Kale plants are sometimes prone to fungal diseases like powdery mildew and downy mildew, which thrive in cool, wet conditions. Powdery mildew presents as white, fuzzy fungal growth on the leaves and stems.
Downy mildew first appears as yellow blotches with brown edges and grey or purple spores underneath.
Treat both with organic copper or sulfur fungicide. To avoid problems with fungal diseases, ensure ample airflow, avoid overwatering, and try not to let water splash the plants’ leaves.
Companion Plants for Kale
Companion planting is a sustainable garden design technique that utilizes the valuable characteristics of certain plants.
Some plants attract beneficial insects, repel pests, and enhance their neighbors’ flavor and overall growth. However, other plants inhibit one another’s growth and should live in separate areas of the garden.
Aromatic herbs like cilantro, caraway, dill, and tansy attract beneficial predatory insects like hoverflies, ladybugs, and parasitic wasps. Rosemary and sage deter pests through their strong scent.
Legumes like beans and peas are excellent companions for leafy greens because they fix nitrogen in the soil through a profitable interaction with soil bacteria.
Alliums like onions and garlic are great for repelling a wide variety of pests, including aphids, cabbage worms, carrot flies, and slugs. However, they should be grown away from legumes as these two plant groups reportedly stunt one another’s growth.
Flowers like marigolds and cosmos are excellent for attracting pollinators to the garden. In addition, they’re also effective pest control plants.
French marigolds produce a natural chemical that kills root knot nematodes when they feed, reducing the overall population of these pests, which also feed on kale roots. They also repel aphids and mosquitoes. Cosmos attracts predatory insects that feed on garden pests.
It’s best to avoid planting crops that are susceptible to similar problems close together. Plant other members of the cabbage family in a different location. Strawberries must also grow elsewhere, as they tend to attract slugs that quickly devastate your kale harvest.
Kale is a delicious and nutritious leafy vegetable that’s easy and satisfying to grow in your garden. Since it’s a cool weather crop, kale grows best in the late spring and early fall.
In mild climates, it’s possible to grow kale as a year-round crop. Growing kale with other veggies and herbs helps to create a healthy, interactive garden ecosystem.
If you found these gardening tips useful, please feel free to share this article about how to grow kale with your friends and family on Facebook and Pinterest who may be wondering, “How long does kale take to grow?”