How to grow kale – from seed to harvest (for beginners)

Kale is a nutritious, flavorful, leafy green that is easy to grow in a home garden. With some planning and care, you can grow kale from seed and enjoy fresh, homegrown kale all season long.

To start, select a spot in your garden with at least 6 hours of sunlight daily.

Kale prefers well-draining soil rich in organic matter, so prepare your soil by adding compost or well-rotted manure before planting.

Once you have chosen your planting spot and prepared the soil, it’s time to sow your kale seeds.

Kale seeds can be started indoors or directly in the garden, depending on the timing and climate in your area.

Kale is an ideal cool-weather vegetable for winter sowing. Learn more in the article: Winter sowing: How to start seeds outdoors in winter

Starting kale indoors – get a jump-start on the growing season

Start kale seeds indoors 6-8 weeks before the last expected frost. Fill seedling trays or pots with potting soil mix and sow the seeds 1,5 cm (1/8 inch) deep.

Starting kale seeds in seeding trays using potting soil is an excellent way for home gardeners to jump-start the growing season.

Here’s how to do it:

Choose a seeding tray

Seeding trays are containers with individual cells or compartments perfect for starting seeds. You can purchase seeding trays at a garden center or online or use an old tray or even an egg carton as a makeshift tray.

Starting kale seeds, look for deeper seed trays, as it makes transplanting easier when moving your plants outdoors.

A deep seedling tray I use for starting kale seeds
Deep seedling trays are ideal for starting kale seeds.

Fill the tray with potting soil

Potting soil is a lightweight, often soil-less mix designed for starting seeds.

Fill the cells of the seeding tray with potting soil, press gently to remove air pockets while ensuring enough room for the seeds to be planted.

Ensure potting soil mix is evenly moist, not wet.

Plant the seeds

Kale seeds are tiny and can be hard to place with accuracy om the soil’s surface.

Plant two seeds in each cell if using a tray with individual compartments or scatter in groups of 3 seeds 10 cm (4 inches) apart if using an open container.

Cover the seeds with a thin layer of potting soil mix and gently press down to ensure good seed-to-soil contact.

Water the seeds

Water the seeds gently using a spray bottle. Keep the soil evenly moist, but be careful not to overwater, as this can cause the seeds to rot.

Place the tray in a warm location

Kale seeds need a warm location to germinate. Place the tray in an area that is between 15-21 degrees Celsius (60 and 70 degrees Fahrenheit). A sunny windowsill or a seedling heat mat can provide the warmth that kale seeds need to sprout.

Kale seeds have a good germination rate around 75% and should sprout within 5 – 8 days.

Kale seeds have geminated and sprout first leaves
Kale seeds sprout first seeds.

Monitor the seeds

Keep an eye on the seeds as they germinate and grow.

Water them regularly and thin out the weaker seedlings once they have sprouted if necessary. You can also transplant the seedlings into pots or the garden once they are large enough to handle if there is no risk of frost.

Keep the soil moist but not soggy, and provide plenty of sunlight until the seedlings are ready to be transplanted.

Starting kale outdoors

If planting directly in the garden, plant the seeds in groups of 5 about 10 cm (4 inches) apart. If you have rows of kale, space rows about 30 cm (12 inches) apart.

Cover the seeds with a thin layer of soil and water gently to help them settle. Mulch the bed and use a protective cover to protect your plants against pests and harmful insects.

As the seedlings grow, thin out the weaker plants to give you about 30 cm (12 inches) between plants.

Caring for your kale plants

Once your kale plants are established, they will require regular watering to keep the soil evenly moist. Mulching around the plants will help control soil moisture while keeping weeds at bay.

Kale is a cool-season crop, so it is best to water it in the morning to allow the foliage to dry out before nightfall. This will help prevent fungal diseases from developing.

In addition to regular watering, kale plants will benefit from applying compost or well-rotted manure as a natural source of nutrients. Kale plants need this extra nutrition to grow and thrive. Plan to feed your plants at least 2-3 times during their growing season.

You can also use grass clippings, a balanced fertilizer or slow-release fertilizer pellets according to package instructions to boost your plants.

Pests and diseases

You should always cover your kale plants as there are so many pests that want to munch on your kale.

Covering your plants help, but manual inspection is vital. As your kale plants grow, keep an eye out for pests such as aphids, snails, and caterpillars.

Snails are just one of many pests that love kale
Snails are one example of pests that love kale.

Many pests can be controlled by handpicking or using a natural pest control method such as a homemade soap spray.

I never use commercial pesticides or insecticides as we grow kale for consumption. And kales are not the easiest plant to rinse or clean when harvested.

Harvesting kale

When it comes time to harvest your kale, snip off the outer leaves as needed, leaving the inner leaves to continue growing.

Kale can be harvested at any stage, but the leaves are typically at their sweetest and most tender when they are young and small.

Harvest gently and avoid getting soil inside the plant’s leaves.

The 3 biggest mistakes I have made over the years

Kale and especially curly kale is a staple ingredient for us at home. And I have learn a lot over the years. Especially from my mistakes.

Here are the 3 biggest mistakes I have made growing kale in our vegetable garden.

1. Not fertilizing enough

When you kale plants are established they need nutrition to grow and thrive.

I spend a lot of time to amend and improve my soil before the start of every growing season. Still, that is not enough.

Kale is a five grower and will produce a generous harvest but you need to feed your plants at least 2-3 times during the growing season.

I have learnt to add a bit more compost when I think the plants have had enough. And my harvests have proven me right.

2. Not taking pests seriously

When I started growing kale I did not even cover my plants.

I was convinced companion planting garlic, basil and marigolds would do they job. And I am sure they helped but my kale plants are like magnets for snails, caterpillars, moths, flies and all kinds of kale-loving pests and insects.

So if you only take one thin from this article, do cover your kale plants.

3. Not enough space between plants

I admit it. I am greedy and want to plant as many plants as possible in every garden bed.

But I have learns that it is counter productive. Too many plants lead to weaker plants and an overall smaller harvest.

I have learnt to thin out the weaker seedling and plants for use in salads and leave the stronger plants to deliver bumper crops.

Overall it gives me more to harvest.

Meet the author: Mattias is an experienced gardener spending most of his free time on his knees among herbs, plants, and garden vegetables. For the past two years, he has been sharing gardening projects and how-to tutorials on the NordicLavender website and YouTube channel.