How to Sow and Grow Kale

Now well-known for its health benefits, kale has grown in popularity over the last few years. Full of nutrients, fibre and antioxidants, it’s also great for adding taste and texture to dishes. Although curly kale is the variety most people recognise, there are many more that are delicious and straightforward to grow. A good-looking addition to any vegetable patch or garden border, it is a great winter crop option.

To keep your patch productive in the colder months, we’ve gathered together key kale growing advice.

What You Will Need

Kale isn’t a very demanding crop. It will grow in a range of soil and temperature conditions. However, to maximise your chances of success, it’s best to plant it in good quality soil in a full sun or lightly shaded area. Keeping the plants sheltered from high winds is also recommended, particularly if you’re growing a tall variety. This should help your kale stay productive between July and October for two years running.

Choosing Varieties of Kale

You might think all kale has leaves that are curly, crispy and green, but this is far from the truth. There are a huge range of varieties to choose from, including: 

• Lacinato (Tuscan Dinosaur, Precoce Di Toscana, Cavolo Nero) has deeper green leaves that are flat, elongated and bumpy with soft stems and a sweet, mild flavour
• Chinese kale has a bitter taste with light green leaves and a thick stalk. It’s also one of the shortest varieties
• Red russian is so-called because of its purple-tinged leaves and stems, its flat, craggy leaves are sweet, earthy and great for salads
• Redbor is one of the most striking varieties because of its bushy, dark-red leaves that have a mild, sweet flavour
• Baby kale is spinach-like in its appearance, with tender, mild leaves. Variations include Kale Garlic, which has a slight aftertaste
• Ornamental varieties have been bred for their looks rather than their taste, with options like Jardin Crimson and Jardin Ivory making an impact in all types of gardens

When deciding which variety to plant, looking at the flavour or visual profile you prefer is a good start. Also consider the size of the plant (in diameter and height) and whether it fits your outdoor space.

How to Prepare Soil for Growing Kale

To give your kale the best possible start, enrich your soil using the ‘no dig’ method or by adding homemade or shop-bought peat free compost. Remove weeds and stones before sowing. 

If you’re planting your kale in containers, then choose a size that will fit your chosen variety. A single plant should fit in a pot with 30cm diameter and depth with no problem. The type of kale you choose may also determine whether you should use a container at all. For example, Cavolo Nero is tall, large and better suited to growing directly in the ground.

Sowing Your Kale Seeds

Although it’s possible to harvest kale leaves before the plant fully matures, some varieties don’t stop growing for around 90 days. If you’re growing other vegetables in your garden, this slow growing season can make it difficult to figure out how much room to leave for your kale. That’s why some growers choose to sow plants indoors before transplanting them into their final plot with plenty of space. 

It’s recommended that you seed indoors around March. To do this, fill a modular tray with compost and plant two seeds in 1cm deep drills. Lightly cover with compost and water well. You may need to take out one of the seedlings if both succeed. 

If you’re planting directly into the ground, do so around a month before the last spring frost or six weeks before the first autumn frost. This is usually between March and June. Do this in prepared ground by creating rows of 1cm deep drills 2.5cm apart. If you’re seeding multiple rows, then make sure there’s 15cm space between them.

Transplanting Your Kale Seedlings

If you’ve sown your kale seeds outside, then you’ll have to thin them out as they grow. Once they’re germinated, move them to be 7.5cm apart. Keep doing this process until they’re between 30cm and 60cm apart, depending on the variety. 

If you’ve sown your kale seeds indoors, then they should have five or six true leaves before they’re transplanted outside. Also make sure you harden them off over a two week period so the plants aren’t shocked when you move them outdoors. Water your seedlings well on their last night outside. Then, you can transplant between April and June by:

• Digging holes deep enough so the lower leaves will be at ground level
• These spaces should be at 45cm intervals
• Take the seedlings out of their containers without disturbing the root system and place them in the holes
• Firm them into the ground and water generously

How to Care for Your Kale

Kale is a relatively easy-care vegetable. Giving them a little extra care as seedlings and young plants will set them up for better maturing. Make sure you’re watering them regularly and removing any weeds so they don’t have any competition. 

Once the kale plants are mature, they should only need watering in dry conditions. Adding a layer of mulch will help keep the soil moist and reduce weeds. Depending on your soil, you should only need to feed kale sparingly. Adding organic mulches can help yields on overwintered crops. 

If you’re growing taller varieties, make sure they’ve got plenty of support. Staking the plants as they get closer to harvest will stop stems from snapping and root systems from being disturbed. This should also be done if there are storms or high winds.

Harvesting Kale

The exact time kale leaves will be at their best depends on their particular variety. However, some young leaves can be taken off the outer edges of the plant when they’re around 10cm to 15cm long. The leaves in the centre of the plant will be ready for harvesting between 50 and 75 days after seeding.  

One of the best ways to harvest kale leaves is using the cut-and-come-again method. This means cutting exterior leaves with sharp pruners or scissors close to the base of the plant. Take just a few leaves at a time and leave the plant for a week or so before returning to it for harvesting. Using this technique will encourage the kale to regrow. You can also cut the whole central plant at the base, minimising root disruption and encouraging resprouting. 

As soon as plants have matured, you can look over your garden one or two times a week for new leaves. This doesn’t just keep your kitchen full, but encourages further growth, keeps pests away and helps with air circulation.

Common Issues When Growing Kale

Although kale is an easy-going plant, it can be targeted by pests, diseases and extreme weather conditions. If you start having problems with your kale, then take a look at the problems and solutions below:

• Holes in your leaves or stunted growth are likely to be caused by cabbage worms, cabbage loopers, cabbage white butterflies, caterpillars or slugs. These can be kept at bay by net covers
• Yellowing leaves and weakened plants can happen as a result of aphids. Repel them by spraying your kale with neem oil
• Spots and crisp, brown leaves are usually a result of harlequin bugs infesting your plants in hot weather. These can be taken off kale by hand, or you can cut off affected leaves
• Tiny holes in your leaves may suggest that flea beetles are present. These can be repelled by putting talcum powder on your leaves
• Rotting leaves are likely to be down to black rot infections. It’s likely because of a lack of airflow and sunlight but can only be stopped my pulling out affected plants
• Wilting leaves are likely to be due to too much heat or too little water. Add shade and up your watering schedule if you spot this problem
• If your leaves are turning purple or pale green and this isn’t because of their variety, it’s likely to be a lack of nutrients in the soil. Test it for pH and add organic fertilisers if needed
• Stunted growth, legginess or weakness in a plant can be caused by too much or little water, nutrients or sunlight

Top Tips for Growing Kale

Planting kale with enough space and giving it enough water and sunlight will give it the best chance of success. If you want to give it even more support, then using companion plants can be helpful. The following vegetables, herbs and flowers are all great options: 

• Sweet alyssum, african marigolds and calendula are colourful and beautiful. They also help repel pests and attract pollinating insects
• Coriander, dill and lemongrass help keep pests down and boost kale growth
• Alliums like spring onions, onions, garlic and leeks have scent and oils that repels pests and keep the soil loose, helping with drainage
• Chilli peppers are a great deterrent for big and small pests, they also grow really well around kale
• Beans help to fix nitrogen in the soil, which is beneficial to kale’s growth
• Cucumbers help maintain the soil’s temperature and keep weeds down

Kale is a good crop for growers of all levels to plant. Whether you fancy adding colour to your borders with an ornamental variety or want to add some crunchy, nutritious vegetables to your kitchen garden, kale will fit the bill. For striking plants packed full of flavour, check out our heirloom kale seeds. Happy growing!

Video – How to Sow and Grow Kale