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How to plant kale seeds outdoors


How to Germinate, Water, and Harvest

Kale (Brassica oleracea) is essentially a form of cabbage that doesn't have the tightly formed head associated with most cabbages, and it's grouped in the cooking greens category with collards, mustard, and Swiss chard. Kale plants can be quite ornamental, with textured and curly leaves that come in shades of green, purple, and other colors. Kale has a relatively fast growth rate and can grow from seed to harvest in about three months. It is best planted in the late winter or early spring and can also be planted in the late summer for a fall to winter harvest. Kale does come back every year, but this biennial plant takes two years to complete its growth cycle—so it grows leaves in its first year, while seeds and flowers develop in its second growing season.

Common Name Kale, ornamental kale
Botanical Name Brassica oleracea
Family Brassicaceae
Plant Type Annual, biennial, vegetable
Mature Size 1–2 ft. tall, 1–2 ft. wide
Sun Exposure Full sun, partial sun
Soil Type Loamy, moist, well-drained
Soil pH Acidic
Bloom Time Spring
Hardiness Zones 7–9 (USDA)
Native Area Europe

How to Plant Kale

Kale is a fast-growing vegetable that does best in a planting location with full sun. Plant kale seeds about 1/2 inch deep, leaving at least 1 1/2 to 2 feet between each plant. High nitrogen content in the soil is important for kale to grow its leaves, so adding a few inches of organic matter like compost to a well-draining soil mixture will encourage a healthy harvest.

When to Plant

Kale can be planted three to five weeks prior to your area’s projected last frost date in the spring. In most regions, gardeners can harvest kale in the summer by planting it at this time. It can also be planted in late summer roughly six to eight weeks before your first fall frost.

Those in warm climates (zone 8 and above) can continue to plant in the early fall for a late fall to winter harvest. Kale takes roughly three months to reach maturity from seed, while cuttings will mature in about one month.

Tip

Cuttings are an inexpensive way to create new plants. Plant your kale in early spring if you plan to take cuttings in late summer. Kale cuttings should be taken in about three months once the plant has become established.

Selecting a Planting Site

Kale grows equally well in pots, garden soil, raised garden beds, and other containers. Kale can grow indoors as long as you have adequate lighting. Soil that’s rich in organic matter and has sharp drainage is ideal, and the planting site also should get ample sunlight. Be sure the kale isn't too close to taller plants that will shade it. Growing kale in a window box can also be successful in south- or west-facing windows, but in very hot climates, east-facing windows can help prevent scorching from the afternoon sun.

Spacing, Depth, and Support

Space kale plants roughly 1 1/2 to 2 feet apart, and plant them at the same depth they were growing in their nursery container. Seeds should be planted around 1/2 inch deep. No support structure is necessary.

Kale Care

The Spruce / Debbie Wolfe   The Spruce / Debbie Wolfe 

The Spruce/Debbie Wolfe 

Light

Kale needs full sun to partial shade in most climates, as the fullest growth will occur when the plant gets six or more hours of direct sunlight on most days. However, if you live in a hot, dry climate, provide your plant with some shade, especially from the strong afternoon sun. Heat can make the leaves wilt and lose their flavor.

Soil

Kale plants like to grow in a rich soil that's high in organic matter with a slightly acidic pH (6.5 to 6.8). The high nitrogen content provided by organic matter is crucial for healthy leaf growth. The soil also should drain well.

Water

Kale needs consistent amount of water to stay healthy, generally growing best in 1 to 1 1/2 inches of water per week. Water your kale plants regularly to keep the soil evenly moist but not soggy. Along with cool temperatures, moist soil helps to keep the kale leaves sweet and crisp, rather than tough and bitter. Mulching around your plants can help to keep the soil cool and to retain moisture.

Temperature and Humidity

The plant is usually considered a cool-weather vegetable and can handle some frost once they're mature. The optimal soil temperature for planting kale is 60 to 65 degrees. All varieties prefer cool temperatures and will be sweetened by a touch of frost. Hot weather turns kale bitter. Kale is a biennial plant, taking two growing seasons (or years) to complete its life cycle, but it's usually grown as an annual. It will collapse if exposed to heavy frosts or snow. But it can be grown throughout the winter in USDA zones 7 through 9 if the winters are mild and there is adequate water.

Fertilizer

When planting, mix fertilizer into the top 3 to 4 inches of soil. Then, feed your kale throughout the growing season, following the instructions on your fertilizer label. Use compost or a high-nitrogen vegetable fertilizer.

Types of Kale

There are many kale varieties, and they're all worth a try. The curly-leaf varieties tend to hang on longer in cold weather. But the flat-leaf types generally become established faster. Here are some varieties to consider:

'Lacinato' kale

Anna Yu/Getty Images

'Redbor' kale

valery_green/Getty Images

'Red Russian' kale

romiri/Getty Images

Kale vs. Chard

Kale and chard have similar appearances. Their leaves are often large, crisp, crinkled, and deep green. Their difference comes in their taste. Kale is generally stronger, with a bitter and earthy flavor. And chard is a much milder green. Plus, kale’s thick stems are typically best removed before eating while chard’s stems may be tenderized by cooking them.

Harvesting Kale

Expect to wait approximately two months for your kale plants to mature from seeds. Check the days to maturity on your seed packet or plant label for more precise timing. Spring-planted kale will be good for harvesting throughout the summer months, but it's especially tasty after a light frost.

You can harvest young kale leaves to use fresh in salads or allow your plants to mature for use as a cooked green. Remove the older outer leaves, and allow the center of the plant to continue producing. Kale will keep in the refrigerator, ideally in the crisper drawer, for about a week.

How to Grow Kale in Pots

Kale is easy to keep in pots. Not only does this make the plant mobile so that you can move it into adequate sunlight and protect it from severe weather as needed, but it also helps to protect it from garden critters, such as rabbits, that might munch on the leaves. Plus, container growth is ideal if you don’t have garden space or the right soil conditions. 

Select a pot with at least a 12-inch diameter. It also should have ample drainage holes. An unglazed clay container is a good option because it will allow excess soil moisture to escape through its walls, helping to prevent root rot. Use a quality potting mix; an organic mix made for growing vegetables is a good option. Transplant your kale into the pot at the same depth it was growing in its previous container, and water it after planting.

Propagating Kale

Kale is most commonly planted from seeds or nursery plants, but it can also be propagated via cuttings. Kale does regrow after cutting, but it requires a specific propagation process. To pick kale to keep it growing healthy, cuttings must be taken from the oldest leaves. Here’s how:

  1. Use gardening shears to cut a stem from the bottom of the plant on its side, choosing one with multiple leaves from the main stem (do not propagate from the plant's center). Remove the leaves on the lower half of the stem. Trim the bottom of the stem right below a leaf node at a 45-degree angle. 
  2. Dip the cut end in rooting hormone.
  3. Plant the bottom half of the stem in a moistened soilless potting mix in a small container with drainage holes. 
  4. Continue to keep the growing medium moist. Roots should develop in a few weeks. If you can gently tug on the stem and feel resistance, you’ll know roots have formed. After that, it’s ready for transplanting.

How to Grow Kale From Seed

Growing kale from seed can begin inside or outside depending on your region. Kale can be direct seeded in the garden or started indoors and transplanted into the garden. You can direct seed in cold climates as soon as the soil temperature is at least 45 degrees Fahrenheit.

  1. Start plants indoors in a seed-starting mix about six weeks before your last expected frost date. Kale seeds germinate quickly in warm soil and should sprout up within five to eight days.
  2. Cover the seeds with about 1/2 inch of soil, and keep the growing medium moist.
  3. Transplant your seedlings from indoors after the danger of frost has passed.

Common Pests and Plant Diseases

Kale is a member of the cabbage family, which is notorious for attracting insect pests and for rot diseases. Kale is susceptible to black rot and clubroot, as well as aphids, cabbage loopers, cabbageworm, cutworms, flea beetles, and slugs. The best defense is to monitor the plants often for signs of eggs or feeding, such as holes in the leaves. Treat problems as soon as they arise.

Article Sources

The Spruce uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.

  1. Kale. Cornell University Growing Guides.

How to grow kale – from seed to harvesting

(Image credit: Getty Images)

Once you know how to grow kale there’s no going back. It’s healthy and tasty, easy to cultivate and looks good in your garden. What’s not to like? 

It’s easy to grow kale from seed, too. Also known as borecole, kale is a member of the cabbage family, a brassica. It is hardy and grows best in cooler temperatures – the cold weather gives the leaves a sweeter flavor.  

Kale is the original superfood. It contains fiber, calcium, vitamins C and K, iron and antioxidants, plus many other beneficial nutrients. It is a versatile green that can be fried, steamed, and even oven-roasted to make a healthy vegetable snack. The young leaves can be eaten raw as a salad or added to smoothies. 

Read on to find out how to grow kale from seed. 

See: Kitchen garden ideas - easy ways to get started

When do you plant kale?

(Image credit: Getty Images)

When you plant kale depends on when you want to harvest the leaves. 

To grow kale as an early summer crop, the seeds can be sown indoors in modules or seed trays in early spring, or sown directly into the ground once it has warmed up in spring. 

'Starter plants can be transplanted outside 3-5 weeks before the last frost in your area,' says Amy Enfield, horticulturalist for Bonnie Plants . 

For a fall or winter harvest, plant out 6 to 8 weeks before the first fall frost. In warmer areas (zones 8, 9 and 10) you can continue planting through the fall. 

How do you start kale seeds?

(Image credit: Future)

If you’re starting the kale seeds off inside, you can simply sprinkle the seeds onto potting compost, lightly cover with compost and water. 

If you prefer, you can soak the seeds in tepid water for 24 hours before sowing. This should  speed up germination. 

If you’re sowing in rows directly into the earth, sow 3 or 4 seeds together, every 12 inches (30cm), half an inch (13mm) deep, allowing 18 inches (45cm) between rows. 

In this clip from Gardeners' World , TV gardening expert Monty Don shows how to plant out young kale plants and advises trampling the soil with your feet to firm it. This will help to hold the plants solid in fall and winter winds. 

See: Small vegetable garden ideas - from layout designs to the best crops to grow

How long does it take to grow kale from seed?

(Image credit: Future)

You can expect to see your kale seedlings germinating in five to eight days. Keep them well watered until you are ready to pot them on or plant them out.

Is kale easy to grow?

(Image credit: Future)

It is very easy to grow kale. It’s a tolerant plant that can survive cold temperatures and shady conditions – just three hours of sunshine is enough although it grows well in full sun to light shade in a well-drained soil. 

If you're transplanting seedlings into your vegetable plot, allow at least 12 inches (30cm) between each plant, and 18 inches (45cm) between rows as they grow into quite sizeable plants. Adding well rotted manure to the earth before planting will get your kale off to a good start, and you can top up with an all purpose liquid plant food to give it an occasional boost. 

Amy Enfield, horticulturalist for Bonnie Plants, says: 'Kale is a fairly fast growing plant. The soil should be kept consistently moist which usually means providing plants with 1-1.5 inches of water each week (water whenever the top inch of soil is dry to the touch), mulching around the plants with finely ground leaves, weed-free hay, straw, pine needles, or finely growing bark will help keep the soil cool and moist. '

A regular watering routine will help to prevent the leaves from wilting in warm, dry weather. 

See: How to grow spinach – in pots, indoors or in raised beds

Does kale come back every year?

(Image credit: Future)

Most kales are biennials, meaning they will take around two years from seedling before they eventually bolt and produce flowers and seeds. However, if you’re growing kale for its harvest of leaves it’s more likely that you’ll replace it every year  and it will be more successful that way. 

You can also treat it as a ‘cut and come again’ crop, where you harvest the tender young top leaves for salads, leaving the stem to overwinter and produce side shoots of bigger leaves for cooking. Monty Don agrees, saying, 'The more you pick it the more fresh leaves come.'

Amy Enfield adds, 'Kale leaves have their best flavor when they’re “kissed” by a light frost, making fall harvests sweeter than spring harvests. To harvest, pick the oldest, lowest leaves first. Discard any that are yellowed or ragged. Take as many leaves as you like, as long as you leave at least four leaves at the top of the plant (the crown). In zones 7-10, kale will produce new leaves all winter long.'

Can you grow kale in containers or raised beds?  

(Image credit: Future)

Kale can grow just as happily in pots or raised beds as it does in open soil. However, the plants can reach up to two feet high when mature, so use a large pot – at least 12 in (30cm) diameter – filled with compost mixed with grit to improve drainage.

(Image credit: Future)

Cavolo Nero – sometimes regarded as a different plant altogether, but it is a type of kale and its name means ‘black kale’, or black cabbage. ‘Nero di Toscana’ has dark, almost black leaves.  

Redbor – Vivid burgundy-colored leaves on a striking plant that would look good in a flowerbed let alone a vegetable patch. The leaves turn an intense shade of purple as the weather turns colder.  

Kapitan – the classic curly kale, with densely curled, deep green leaves

Yurok – a hybrid Lacinato-type kale, highly recommended by Don McCulley, owner of Swallowtail Garden Seeds , who says it 'has an exceptionally long harvest window. Puckered blue-gray leaves maintain their color and tenderness longer on the plant than other kale. Its robust, 30 inch tall plants produce heavily, and are highly resistant to frost and heat.'

See: How to grow microgreens – a guide to growing superfoods

Common problems when growing kale

(Image credit: Future)

Kale is fairly resistant to pests, compared with other members of the brassica family, however young plants will need some protection from birds. Pigeons in particular can reduce the tender leaves to ribbons. Covering your plants with insect proof netting will help to keep off birds, caterpillars (the net will prevent butterflies laying eggs on the leaves), and cabbage root fly.

Amy Enfield adds: 'There are several garden pests that like to munch on kale – cabbageworms, harlequin bugs, and cabbage aphids. Cabbageworms prefer cabbage, broccoli, and cauliflower to kale, but if you see the cabbage white butterflies flying around your plants, keep your eye out for the velvety green caterpillars. Black and orange harlequin bugs usually feed on old, stressed kale plants. Gray-green cabbage aphids are usually found clustered in the folds of frilly kale leaves. Badly infested leaves can be picked off and discarded.'

Karen is the houses editor for homesandgardens.com and homes editor for the brand’s sister titles, Period Living and Country Homes & Interiors, and an experienced writer on interiors and gardens. She loves visiting historic houses for Period Living and writing about rural properties for Country Homes & Interiors, and working with photographers to capture all shapes and sizes of properties. Karen began her career as a sub editor at Hi-Fi News and Record Review magazine. Her move to women’s magazines came soon after, in the shape of Living magazine, which covered cookery, fashion, beauty, homes and gardening. From Living Karen moved to Ideal Home magazine, where as deputy chief sub, then chief sub, she started to really take an interest in properties, architecture, interior design and gardening. 

When and how to plant cabbage

Cabbage is most often bred in seedlings. However, for a good harvest, it is not enough to grow healthy and strong seedlings - they must be planted correctly and on time in open ground. Beginner summer residents often have questions related to this procedure.

The very first difficulty is choosing the right variety. Depending on the ripening period, cabbage (we are talking about the most common type - white cabbage) is early (60-90 days from germination), medium (100-120 days) and late (more than 150 days). If your goal is to eat a fresh vegetable and cook soups, main dishes or salads from it, then choose early varieties. They grow quickly and have a more delicate taste. But if you expect to use cabbage for pickling, pickling or storage, then you can’t do without varieties of late ripening.

What kind of soil cabbage likes

In order for the cabbage to please with a harvest, you need to take care of choosing a suitable place for the garden bed where you will plant the seedlings.

First, let's figure out what kind of soil cabbage needs for normal growth?

  1. Cabbage likes neutral soil. If the soil in your area is acidic, you need to do it with liming. To do this, in the fall, add slaked lime or chalk to the future bed. In the spring, gypsum or dolomite flour can be used for this purpose. The amount of substances needed to deoxidize the soil depends on the level of its acidity.
  2. Cabbage in acidic soils or in conditions of high temperature and humidity is often affected by the most terrible cabbage disease - clubroot. There are no effective ways to deal with clubroot, so the only way to protect your plantings from the disease is preventive measures. Use fungicides as a preventive measure. A week before planting cabbage seedlings in open ground, treat the ground with a Bordeaux mixture (dissolve 10 tablespoons in 10 liters of water) or Fitosporin (1 tablespoon of the drug per 10 liters of water), and then add ash. The fungicide will protect plantings from fungal diseases, and the ash will reduce the level of acidity and enrich the soil with trace elements necessary for cabbage.
  3. Cabbage needs a sunny area with a deep - more than 2 m - level of groundwater. Although this vegetable is moisture-loving, however, constant stagnation of water negatively affects its root system and can lead to rotting of the roots.

When choosing a place, also pay attention to the predecessors that grew here last season. It is best to plant cabbage after nightshade, legumes, cucumbers, carrots, onions or garlic. Cabbage can be returned to its original place no earlier than after 3-4 years. If the vegetable was affected by keel, then this period increases to 7 years - that is how much keel spores live in the soil.

When to plant cabbage outdoors

The time of planting cabbage seedlings depends not only on the region, but also on the type of cabbage: early-ripening varieties are planted earlier, varieties of late ripening - later.

To determine exactly when to plant cabbage outdoors in your area, check the weather and plant appearance.

Harden off seedlings two weeks before planting seedlings outdoors. In the first 3-4 days, take out the plants (or open the windows in the room where the seedlings are located) for several hours. Increase the amount of time spent outdoors every day. 2-3 days before transplanting, leave containers with seedlings outside for the whole day. Seedlings prepared in this way will more easily endure the stress associated with changing the place of cultivation.

How to plant cabbage

Plant cabbage seedlings outdoors on a cool overcast day. The ideal option is before the rain, then the seedlings will quickly take root in a new place. A few hours before transplanting, water the seedling containers well with water so that the roots are less injured.

The distance between the rows of cabbage depends on the ripening period of the crop:

Rules for planting cabbage seedlings in open ground:

  1. On the prepared bed, make the required number of holes, the size of which should slightly exceed the volume of the earthen coma.
  2. At the bottom of the hole, pour a matchbox of wood ash and crushed eggshells (protection from the bear), mix everything with soil and lower the seedlings into the hole. If the site has heavy, dense soil, also add sand or low-lying peat to each hole, which will loosen the soil. Fill the planting hole with earth and carefully tamp.
  3. Make a small trench around the plant. When watering, the water will go from there directly to the roots of the seedlings and will not spread over the garden.
  4. Thoroughly water the cabbage.
  5. If the weather is sunny, cover the planted seedlings with newspapers or agrofibre. After rooting the seedlings, the protection can be removed.

To prevent overgrown seedlings from being broken by strong winds, bury them in the ground to the first true leaves.

How to care for cabbage outdoors

What is the further care of the planted seedlings?

First, watering . Make sure that the soil around young plants does not dry out. When they grow up, you can water the cabbage every other day, adding about 2 liters of water under each bush.

Second, loosening and hilling . Frequent watering makes the soil denser, and a crust forms on its surface. Because of it, the access of air to the roots of cabbage is difficult and the plant develops worse. For this reason, regularly loosen the soil around the bushes, destroying the compacted soil layer. However, watering not only contributes to the formation of an earthen crust, but also exposes the lower part of the cabbage bush, so during each loosening, add earth to each plant.

Third, feeding . Feed the transplanted seedlings for the first time two weeks after planting in open ground. To obtain the necessary nitrogen during this period, apply organic fertilizers or urea. The second time (after another three weeks), feed the cabbage with a complex mineral fertilizer.

Fourth, pest control . Not only we love cabbage - in nature there are a lot of people who want to feast on its juicy leaves. The main and most common enemies are cruciferous flea, caterpillars, snails and slugs. After their invasion, cabbage leaves can turn into a real sieve. To prevent this from happening, destroy pests by any means available to you. We already wrote about folk remedies for pest control of cabbage:

Properly cared for, cabbages will surely delight you with a rich harvest of healthy and crispy cabbages.

outdoor planting and care, cultivation, diseases and pests

Author: Elena N. https://floristics.info/en/index.php?option=com_contact&view=contact&id=19 Category: Garden plants Published: Last edited:

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