Start these 14 Brassicas from Seed This February

For many regions, February is a bridge between seasons. At the tail end of winter, it’s still not quite spring. But this is prime time for preparing brassica transplants indoors or direct sowing cold-hardy brassica crops under protection.

Depending on your growing zone, you can seed a variety of brassicas in February, including kale, cauliflower, radishes, and arugula. These “cole crops” enjoy cool weather and consistent moisture.

In northern regions with short growing seasons, it is especially important to start slow-maturing plants like Brussels sprouts and cabbage indoors so they have time to fully develop outside. In areas with hot summers, you must start brassicas early to avoid problems like bolting and bitter leaves. Southern gardeners are usually more successful when they grow cold-weather brassicas like kale and cauliflower in very early spring. 

Many brassica cultivars are variants of the same species, Brassica oleracea. For example, broccoli plants have been bred for an enlarged central flower, while Brussels sprouts grow lateral buds that resemble mini-cabbages along the stem.

Kale and collard greens are bred for looser leaves, while kohlrabi were selected for enlarged base stalks. You will notice that all of these plants look similar in the seedling stage and are susceptible to the same pests and diseases in the garden.

Brassicas to Start Indoors in February

In spite of their many confusing names, most brassica vegetables are grown in a similar way. You can start seeds indoors in large cell trays in late winter or early spring (6-8 weeks before your last frost date). They will be ready to transplant in 4-6 weeks. 

These cool-climate crops don’t mind the chill of early spring weather. Light frosts are fine for young plants, but only mature plants can handle extreme cold. It is helpful to use row cover or a cold frame to protect young plants from cold nights and early-season pests like flea beetles. 

Kale

Why buy bunches of bland green kale from the grocery store when you can grow unlimited kale in all sorts of unique colors, shapes, and flavors? This infamous cold-weather “superfood” crop is extremely easy to grow from seed.

If you start the seeds in very early spring, a single kale plant can provide you with nutritious leaves for the entire season. They will grow into hefty stalks that produce an endless supply of new leaves. As you harvest the older lower foliage, kale plants continuously produce young greens from the top. 

By continuously harvesting, watering, and removing flowering stalks, you can usually prevent kale from bolting in summer’s heat. When fall arrives, the same plants will begin to sweeten with frost. In many climates, they will even overwinter.

Start this brassica in February by sowing seeds indoors 6-8 weeks before your expected last spring frost. Sow them ¼” deep in 4-cell or 6-cell trays filled with a well-drained soil blend. Keep at room temperature in bright sunlight. Although these plants benefit from cold weather at maturity, the baby seedlings still need warm soils. 

If you want to direct seed, use a soil thermometer probe to check that soil temperatures are above 60°F (16°C). However, I have grown thousands of bunches of kale with the more reliable method of sowing indoors around February or March. The plants will be ready to transplant when they have several sets of true leaves and are about 6” tall, usually within 4-6 weeks of seeding. Remember to thin your cell trays to just one seedling per cell. Transplant with 18-24” of space between kale plants. 

Try ‘Lacinato’ or ‘Dazzling Blue’ dinosaur kale for a crinkly delicious texture. If you want to make kale chips, plant ‘Dwarf Blue Curled’ kale for extra dense leaves that absorb oil and flavor. For extra cold-hardy plants that can overwinter, try ‘Red Russian.’ For vibrant colors, grow ‘Redbor.’

Cauliflower

From classic white heads to psychedelic swirly ‘Romanesco,’ cauliflower is an incredibly versatile vegetable in the kitchen. However, many gardeners struggle to produce those big, dense heads they see in stores. To remedy this, begin cauliflower planting indoors in early spring 4-6 weeks before your last frost. Be sure to select seed varieties labeled for spring production, such as ‘Snowball.’ 

The rounded black seeds should be sown ¼” deep and take 8-10 days to germinate. Provide consistent moisture and warm soils during the early stages. After germination, cool growing temperatures around 50-60°F (10-16°C) are ideal.

Direct sowing is not recommended for cauliflower, as the plants are quite susceptible to pests like aphids and slugs. Instead, wait until the seedlings reach 4-6” tall and have several sets of true leaves. Transplant out with a minimum of 24” between plants and rows. It is very important that you give cauliflower plenty of space. Otherwise, it won’t produce a firm central head.

If you want pure white cauliflower, ensure that the leaves curl over the head so it is not exposed to the sun. If the leaves are not naturally covering the cauliflower head, you can use a rubber band or twist tie to secure them in the center while the heads develop. 

Cabbage

Whether you enjoy fresh coleslaw, home-fermented kimchi, or a hearty cabbage soup, this brassica shines best in early spring. If you start these seeds indoors in February, you will have strong cabbage seedlings to transplant by early April. Full-size cabbage plants can take up to 110 days to mature, so an early start is extra important in areas with a short growing season or regions with hot summers. You want to plant cabbage at the perfect time so it can mature while the weather is still fairly cool.

This February, start cabbage seeds 6-8 weeks before your last frost date in 4-cell or 6-cell trays. A compost-rich soil blend and consistent moisture are essential for strong early growth. Be sure to thin the seedlings, as overcrowding will inhibit head formation. When they are ready to transplant, give cabbage plants plenty of space to open up and spread out. Some varieties need up to 2 square feet per plant.

If large cabbages are intimidating, try a mini variety like ‘Caraflex’ cone-shaped cabbages. In hot climates, try a slow bolt variety like ‘One Kilo Slow Bolt Napa’ cabbage. Premature bolting (going to flower and seed) is a major issue with this brassica and can quickly ruin your summer coleslaw dreams.

Broccoli

The nutritious dark green florets of broccoli can be surprisingly sweet and flavorful when grown in the chill of early spring. Early season varieties are best started indoors 6-8 weeks before your last frost.

Sow seeds ¼” deep in cell trays with soil temperatures around 70°F (21°C) and ambient temperature around 60°F (16°C). You will notice that broccoli seedlings look very similar to cauliflower, cabbage, and kale. Remember to label your seed trays so you don’t get them confused!

After 4-6 weeks of growth, broccoli will be ready to transplant. The seedlings should have strong root growth and several sets of true leaves. It’s important to harden off broccoli seedlings so they can slowly acclimate to colder outdoor nights. I prefer to keep them in a protected area like a patio for a few days before putting them in the ground. Then, I cover the plants with row fabric to add a little extra insulation. 

If your broccoli has failed to produce big central heads in the past, be sure that you are thinning the seedlings to 1 plant per cell. Space transplants are at least 12-18” apart and provide plenty of compost and moisture but don’t allow the soil to become soggy.

Broccolini

Sometimes called sprouting broccoli, rapini, or Chinese broccoli, broccolini is the playful, tender cousin of broccoli heads. They mature more quickly than broccoli and are easier for beginners who have had trouble growing full broccoli heads. These plants produce abundant side shoots all season long. The stems and florets are very tender and taste delightful when grilled. They also make far less of a mess to prepare in the kitchen. 

I prefer to grow broccolini over broccoli because the plants are like a gift that keeps on giving. Although some broccoli plants will produce a few side shoots after you pick the central head, a broccolini plant will literally send out sprouts all spring, summer, and fall. If you keep up with harvests and watering, the plants are less prone to bolting.

Seed broccolini indoors with the exact same method as broccoli and cauliflower. When the mature plants begin to send up shoots, gently snap them at the base and return once or twice a week to check for new sprouts.

Bok Choy

This delicious ancient Asian green can be grown as a full-size head or baby bok choy. I prefer the latter because the plants mature as quickly as 35 days and are easy to roast whole or slice into sautes. These mini brassicas perform excellently in containers and are very beginner-friendly. The crunchy, white stems and tender leaves have a mild flavor perfect for stir-fries.

Bok choy thrives in cool weather and can be transplanted or directly sown. The seeds germinate best when sown ¼” deep in soils at least 60°F (16°C). Use a soil thermometer probe to check your garden beds, or start the seeds in smaller cell trays and transplant out after 2-4 weeks before your last frost date. 

Bok choy is prone to bolting in hot weather, so it’s best to get this crop in and out of the garden in the spring. Fortunately, the little yellow bok choy flowers are also edible and can be used like raab or rapini. Use row cover to keep flea beetles away from the pretty leaves. 

Brussels Sprouts

If you’ve ever looked closely at a mature stalk of Brussels sprouts, it makes perfect sense that this vegetable is a very close cousin of cabbage. You can grow the plants in almost the exact same manner. With tight clusters of leaves like little cabbages along the stalk, Brussels sprouts have a unique growth like a little palm tree. They are surprisingly versatile and enjoy cold temperatures. However, they require early seeding and row cover to avoid pests and bolting issues.

Start Brussels sprouts indoors 4-6 weeks before your last frost date. This is a crop you’ll want to grow once in the spring and again in the fall. With a February sowing of this brassica, you can harvest the sprouts by late May or early June, starting with the largest bottom heads and working your way up as they grow.

Aphids are the biggest problem I’ve encountered with Brussels sprouts. They get inside the tight balls of leaves and quickly turn to nasty infestations. To prevent them, plant lots of fragrant companion plants like onions, white alyssum, chives, and thyme. If you notice early signs of aphids like sugary sap or a gathering of ants, spray the plants with a moderate blast of water to knock the aphids off, then apply a diluted solution of neem oil.

Kohlrabi

With its alien-like bulbous shape, kohlrabi sometimes gets overlooked at the grocery store. Kohlrabi may look like a turnip or root, but it’s actually an enlarged brassica stem. This unique vegetable tastes far better when harvested young, as the older plants can become very hard and difficult to cut.

Young kohlrabi such as ‘Purple Vienna’ can be incredibly tender and juicy, almost like biting into an apple! They have a slightly nutty or peppery flavor and a tremendous amount of vitamin C. 

Kohlrabi can be transplanted or direct sown, as long as the seeds germinate in soils warmer than 45°F (7°C). To start larger plants indoors, plant kohlrabi seeds ¼” to ½” deep in cell trays 4-6 weeks before your last frost date. For baby kohlrabi, direct sow outdoors 3-4 weeks before your last frost date with 4” of space between plants and 12” between rows. 

Begin harvesting when the bulbs are 2-3” in diameter. Cut the stem just at the line with pruners or a knife. Be sure to catch them young! Anything larger than a tennis ball will lose its sweet flavor and potentially develop a woody, pithy texture. 

Collard Greens

You don’t have to live in the Deep South to grow collard greens. In fact, this southern classic actually does best in cold weather. Mature collards are very frost-tolerant and thrive in early spring. The large, deep-green leaves make fantastic wraps or stewed greens with beans and cornbread. The cabbage-like plants are also heat tolerant, which means you can keep them in the garden for a continuous harvest throughout the season, much like your kale plants.

Start collards indoors 4-6 weeks before your last frost and plant out once soil temperatures are above 55°F (13°C). These brassica seeds should be sown ½” deep in 4-cell or 6-cell trays. They are ready to transplant when 4-6” tall. Provide 18-24” of space between plants and begin harvesting the lower outer leaves once they are larger than your hand.

It’s helpful to use a knife when harvesting young plants so you don’t accidentally uproot them. Once the plants are more mature, you can snap the stems from the central stalk as needed.

Brassicas to Direct Seed in February

If your soil is defrosted and workable, there are also many brassica seeds you can start by direct sowing outdoors in February. These grow especially quickly in low tunnels, cold frames, or under row fabric. Amend with compost before seeding, and use drip irrigation or soaker hoses to keep young plants hydrated.

Arugula

Also known as rocket, arugula is a peppery mustard family member that gets spicier in the heat. If you dislike the intense flavor of some arugula, try growing ‘Astro’ in early spring and harvesting the leaves while young. 

You can seed arugula outdoors as long as the soil temperature is at least 40°F (4°C). Plant the seeds ¼” deep and gently dust over them with soil or vermiculite. Maintain consistent moisture and wait 10-15 days for them to emerge. I prefer to grow arugula in dense rows to harvest like salad greens. This means you can scatter the seeds about 4-6” apart in rows 6” apart. For larger leaves, widen the spacing. 

Once the leaves are about 4” tall, use the “cut and come again” harvest method by grabbing a handful of leaves and cutting at the base an inch above the soil. The growing tip will regenerate a new round of arugula within a few weeks. Row cover is very helpful for this early spring green because flea beetles can eat a lot of ugly little holes in arugula plants.

Baby Kale Mix

If you prefer your kale tender and small for raw eating, try direct sowing a baby kale blend like ‘Premier Blend’ or ‘Red Russian Baby Greens.’ These plants perform excellently in containers and germinate in soils around 40-50°F (4-10°C). If you are unsure about whether you can sow, use a soil probe to check the soil temperature several inches deep in your beds. I’ve found that baby kale mix is best planted 2-4 weeks before your last frost date, often around late February for an early April harvest. Sow a new succession every 2 weeks for a continuous supply.

Broadcast or scatter baby kale seeds approximately ¾” apart and ¼” deep. Provide consistent moisture and wait 25-30 days to harvest when they reach 2-4” tall. Use the “cut and come again” method to get multiple harvests from the same patch.

Radish

Spring radishes are a special treat on salads or fresh with a cheese platter. These rapid-maturing brassicas are perfect for impatient gardeners because they take less than a month to mature. The key to great radishes is consistent moisture and an early harvest. Don’t let your radishes get any larger than a golf ball, or they can become pithy and hard.

Radishes take up very little space and are great for containers or small beds. They will germinate in soils as cold as 40°F (4°C). Seed about ½” deep with 2” of space between plants. Repeat successive sowings every 1 to 2 weeks throughout the spring. Radishes become spicier in warm weather but tend to remain sweet and tender as long as temperatures are cool.

Turnip

Have you ever tasted a fresh turnip that was sweet, crisp, and juicy like an apple? Salad turnips are beautiful white globes that mature quickly in spring weather and maintain a delightful texture for fresh eating or roasting. Most people turn their noses up at turnips due to their strong flavor, but Tokyo or ‘Hakurei’ turnips are mild and sweet when grown in cool weather.

You can direct seed these brassicas up to 4 weeks before your last frost date. The spacing between seeds will determine the size of the root. I prefer to plant Hakureis 2-3” apart and harvest them at golf-ball size or slightly larger. Row cover will protect young leaves so you can enjoy them in salads.

If you have problems with wireworms damaging the pretty white skins, try increasing your soil drainage and avoiding overirrigation. Diatomaceous earth or wireworm traps like a buried piece of raw sweet potato may help. Just don’t forget to remove the sweet potato once the little worms infest it!

Mustard Greens

We can’t discuss the mustard family without touching on mustard greens! Most of us think of mustard as the seeds used in the famous condiment, but mustard greens have the same spicy flavor with even more nutrition and versatility.

While most people don’t like mustard greens on their own, I always grow a small patch of mustard greens to mix in with my salad lettuce. Mustard plants are remarkably resilient and easy to plant in the chilly soils of February. Their strong smell is also helpful as a companion plant for deterring pests.