RHS Growing Guides
How to grow kale
Our detailed growing guide will help you with each step in successfully growing Kale.
Getting Started
Thanks to its ‘superfood’ status, kale has enjoyed a dramatic rise in popularity in recent years. Luckily it’s easy to grow, productive and looks great, providing both baby salad leaves and tasty, nutritious greens for cooking or adding to smoothies. It’s particularly valuable in winter, providing fresh leaves during the coldest months.
Kale plants provide plentiful pickings through autumn, winter and spring
You can use kale as a cut-and-come-again salad crop when young, and/or as greens for cooking, ready to pick from autumn through to spring. The leaves can be harvested over many months, and regular picking encourages more to grow.
Month by Month
Jobs to do now
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Choosing
Kale comes in many attractive varieties, adding colour and texture to veg plots
Some varieties are particularly suited as salad crops, especially those with colourful leaves, such as ‘Red Russian’, and some suppliers sell packets containing a mix of salad varieties. Kale is also quick and easy to grow as microgreens on a sunny windowsill – all varieties are suitable, but red or purple ones in particular look great in salads.
For the most reliable varieties, look for those with an RHS Award of Garden Merit (AGM), which shows they performed exceptionally well in our growing trials – see our list of AGM fruit and veg (135kB pdf, includes borecole/curly kale) and our Recommended Varieties below. You can also see many crops, including kale and other brassicas, in the veg plots at the RHS gardens, so do visit to explore how they’re grown, compare the varieties and pick up useful tips and inspiration.
What and where to buy
Kale seeds are widely available in garden centres and from online seed suppliers. Young plants may also be available in spring and early summer, from the same sources.
Recommended Varieties
Preparing the Ground
Kale prefers rich, well-drained, firm soil, but will grow in most soil types and conditions. It likes sun, but will also cope in light shade.
To prepare the ground, weed it thoroughly and dig in plenty of well-rotted manure or garden compost. Then rake the soil level and firm it well. Alternatively, if you're practicing no-dig, mulch the soil with organic matter ahead of sowing or planting directly into the mulch.
Sowing
Kale is easy to grow from seed sown indoors or outdoors, in spring and early summer. Most varieties grow into large plants, so need plenty of ground space. However, there are several more compact varieties, ideal for containers and smaller plots. Kale should be grown with other cabbage relatives in crop rotations, to reduce the potential build-up of soil-borne problems in the veg plot.
If grown as a salad crop, young kale plants can be kept small and need far less space than mature plants. Sow small batches over several weeks, in the ground or in containers, to provide baby salad leaves over a long season. Kale can also be grown as microgreens on a sunny windowsill.
Sowing indoors
You can sow kale indoors from March, to get an early start. Indoor sowing also keeps seedlings safe from slugs and snails, and is a good option if you have club root disease in your soil, as the plants develop a healthy root system before being transplanted into the ground.
It’s best to sow in a modular tray, to keep root disturbance to a minimum when transplanting outdoors in late spring/early summer. Fill the modules with peat-free multi-purpose compost, water well, then make a 1cm (½in) deep hole in each one. Sow two seeds in each hole, then cover with compost. If both germinate, remove the weaker seedling, then keep in bright light and water regularly. For more sowing tips, see our guides below.
Kale is quick and easy to grow as microgreens on a sunny windowsill at any time of year. Sow the seeds into a small seedtray of damp peat-free seed compost. Water regularly, and in just two or three weeks you’ll have tasty nutritious seedlings to add to salads and sandwiches.
Sowing outdoors
Like most large brassicas, kale is sometimes sown into a separate seedbed, then later transplanted to its final growing site at a much wider spacing. This is because it would take up a lot of room on the veg plot during the prime growing season. However, you can also sow it straight into its final site, to avoid transplanting.
You can sow kale seeds outdoors from March to June. Choose and prepare your sowing site as explained above, make a shallow drill about 1cm (½in) deep, then water along the base if dry.
If using a seedbed, sow the seeds thinly along the drill, 10-15cm (4-6in) apart, or thin out the seedlings to that spacing if sown more thickly. Young plants will be ready to move to their final growing site 6-8 weeks after sowing (see Planting).
If sowing in their final position, sow three seeds approximately every 45cm (18in) along the drill. Spacing will vary according to the variety. Large varieties can be sown 60cm (24in) apart and compact varieties sown 30cm (12in) apart – check individual seed packets for details. After germination, thin out each cluster of seedlings to leave just one at each point. Space rows at least 45cm (18in) apart.
When growing as a salad crop, just sow direct into their final position, spacing seeds about 7.5cm (3in) apart. Sow little and often for a regular supply of young leaves.
It’s easy to sow kale for a quick salad crop, with little or no thinning needed
Sowing in containers
For salad plants – scatter the seeds thinly, cover with about 1cm (½in) of compost, then water well.
For mature kale – choose a compact variety, such as ‘Dwarf Green Curled’, and sow direct into a large container at least 30cm (12in) wide and deep. Sow three seeds every 30cm (12in), then when the seedlings appear, thin out the cluster to one strong seedling.
For more container-growing tips, see our guides below.
Planting
In late spring or early summer, move young kale plants to their final growing position when they’re 10–15cm (4–6in) tall. This applies to plants sown in a seedbed, raised from seed indoors or newly bought plug plants. Harden off indoor-sown plants first, to acclimatise them to outdoor conditions.
Carefully lift each plant individually, or remove from the modular tray, trying not to disturb the roots. Set them in their new planting holes more deeply than before, with the lowest leaves at the soil surface, so they root in deeply. Kale can grow into large top-heavy plants that need to be well anchored in the soil. Firm each plant in and water well.
For growing as mature plants, space them 30-60cm (12-24in) apart, depending on the variety. Wide spacing is crucial to give them plenty of light and air, which helps them to crop successfully and deters fungal diseases. If growing purely as a baby-leaf salad crop, spacing can be much closer, about 7.5cm (3in) apart. Protect the young kale plants from slugs and snails and cover with fine-mesh netting to avoid insect and bird damage.
Planting in containers
Kale is ornamental as well as edible, looking great in a large pot on a sunny patio
Plant Care
Watering
Water seedlings and young kale plants regularly, so the soil doesn't dry out. After that, plants should only need watering during prolonged dry spells. Plants in containers need regular watering to stop the compost drying out. For water-saving tips, see our guides below.
Mulching
If growing kale to maturity, apply a thick layer of mulch, such as well-rotted manure or garden compost, around plants to help hold moisture in the soil, reduce the need for watering and deter weeds. Mulching is not usually necessary nor practical around baby-leaf crops.
Feeding
Feeding isn’t usually needed, except on poor soils or when growing in containers. An organic-based nitrogen-rich fertiliser will give plants a boost.
Weeding
Keep young plants weed-free, to reduce competition for light, water and nutrients. Regular weeding throughout the growing season also helps to maintain good airflow between plants, which deters fungal diseases. See our tips on controlling weeds.
Supporting tall plants
In autumn, insert sturdy bamboo canes to support tall kale varieties, especially in exposed locations. This will prevent winter gales buffeting these top-heavy plants and potentially loosening the roots.
Protecting the crop
Fine-mesh netting protects kale from insects and pigeons
Harvesting
When growing as a cut-and-come-again salad crop, start harvesting as soon as plants reach 10–15cm (4–6in) tall. Either pick individual leaves from several plants, or cut the whole rosette of leaves from a plant, in which case it should re-sprout to provide another crop.
Problems
Kale is generally robust and hardy, producing a large crop of leaves over many months. However, as it’s a brassica, it can be damaged by a number of brassica-loving creatures and is susceptible to several brassica diseases – for prevention tactics and more details, see Common problems, below.
Get involved
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