How to grow kale: Sowing seeds, pest prevention, and harvesting tips

How to grow kale: Tips for planting, preventing pests, and harvesting healthy plants

by Comments (3)

This post may contain affiliate links. If you click on an affiliate link and make a purchase, we receive a small commission at no extra cost to you. Find our full disclosure here.

I’m one of those weirdos who loves kale. While I occasionally make kale chips, pesto, or use the young leaves in a kale Caesar salad, I eat the leaves the most either steamed or stir fried, or in soups. I also like to plant kale in my ornamental containers. It’s a perfect double-duty plant, because it adds interesting foliage and you can harvest some of the leaves for meals. Learning how to grow kale is pretty easy. Unfortunately its nemesis, the cabbage worm, can crush—or rather eat—all your kale-growing dreams very quickly. Here are some tips on raising healthy kale plants.

Varieties of kale to grow

There are many different varieties of this super-healthy member of the Brassica oleracea family, which also includes broccoli, cauliflower, kohlrabi, Brussels sprouts, and cabbage.

My favourite varieties of kale include Vates Blue, a curly variety. Curly kale has these wonderful, ruffled leaves. When I use it, I cut around the tough stems and toss them in the compost. If I’m stir frying the leaves, I find sometimes the curls become a bit crispy, which adds a nice crunch to a dish. If I eat the leaves raw, I pick them when they’re quite small.

'Green Curls' container kale

This is a lovely variety from Renee’s Garden called ‘Green Curls’. It’s a container variety, but I’ve also planted it in my garden.

Lacinato kale, also referred to as Tuscan or Dinosaur, has those longer, narrow crinkly-looking leaves. It’s delicious steamed and stir fried. It’s also really striking in a garden.

When looking for seeds, you can find a range of hues and leaf shapes, from the purple-red veins and blue-green leaves of Red Russian, to the rich purple-red of mature Redbor kale.

dinosaur kale

Dinosaur kale is a great variety to add to containers, or if you want to add interesting foliage to an ornamental garden. Of course it tastes great, too.

How to grow kale from seed

In the past, I’ve bought kale seedlings in the spring, but nowadays, I grow my kale from seed. I’ll direct-sow it in one of my raised beds in March or April, depending on the spring we’re having (i.e. if the soil has thawed). Kale is cold tolerant and prefers temperatures, between 55 °F and 75°F (13°C to 24°C). You can sow seeds closer together if you’ll be harvesting for baby kale leaves. Read the seed packet carefully to determine how big mature plants will get, so you can determine spacing accordingly (usually about 45 to 60 cm [18 to 24 inches apart]).

I’ll also sow kale seeds under my grow lights to give it a head start. My grow light stand has a capillary mat and reservoir, which waters from underneath. If my seeds aren’t sown in that setup, I use a mister spray bottle to water the seeds in their cells or small pots, so the seeds and subsequent delicate young seedlings don’t get washed away.

kale seedlings in a pot

Kale seedlings in a pot. These are a container variety, so I grew them in a “salad bowl,” but I’ve also planted them out in the garden.

How to grow kale from transplants

Kale itself is full of nutrients, but it needs lots of nutrients to grow, especially nitrogen. Add a layer of compost (about two inches) to the garden before planting. I top-dress my raised beds with compost in the fall, so they’re ready for early-spring sowing and planting. Whether you’ve purchased seedlings, or grown your own, use a chopstick to gently tease your seedling out of the cell pack or tray and plant it in the garden. Keep your seedlings well watered and watch for pest damage. Fertilize regularly as part of your summer routine using an organic fertilizer.

Growing kale to add to ornamental arrangements

Often you’ll see ornamental kale varieties at the garden centre, especially in the fall, to be used in autumn arrangements. I like to grow my own foliage. I usually pop a couple of kale plants out of my garden to add to my pots. They add a lovely texture to my containers. Before the winter, I dig them back into my raised bed. That’s how I got my kale plant with the bark on it, as shown below.

moody fall container

This moody fall container features one of my favourite autumn palettes. This planting features Vates Blue and a purple variety.

Dealing with kale pests

The aforementioned cabbage worms are the main pest I’ve dealt with on my kale plants. Apparently groundhogs are a healthy bunch, because my friend caught one eating her kale in one of her raised bed containers.

A few years ago, I was on a PBS gardening special called Growing Wisdom. It featured my upcycled lettuce table where I’d planted a variety of baby salad greens, including baby kale. In between takes, I looked down at one point and tried not to reveal my absolute horror that the kale leaves were absolutely covered in wee cabbage worms. I hadn’t noticed because they were only on the row of kale plants! Luckily the camera didn’t notice either.

Cabbage worms can wreak havoc in a very short period of time. Jessica outlines some great tips for dealing with them in this helpful article. Inspect young seedlings regularly and carefully, especially if you see small bits of leaves start to disappear.

Protecting your kale crops with row cover

This year, I decided I’d cover one of my raised beds in lightweight floating row cover. When I wrote my first book, Raised Bed Revolution, I added 1/2-inch conduit clamps to the inside lengths of one of my raised beds that could accommodate 1/2-inch pex pipe. This flexible material can easily be cut with an xacto blade and forms a perfect semi-circle that when inserted into the clamps, creates a mini hoop house. I use lightweight floating row cover that lets sunlight and rain through. I hold the ends in place using spring clamps like these around the edges of the raised bed.

My mini hoop house setup protects my Brassica crops—kale, kalettes, broccoli, and cabbages—from cabbage worms.

My mini hoop house setup protects my Brassica crops—kale, kalettes, broccoli, and cabbages—from cabbage worms.

My original intention was to use this bed as a season extender, but I got quite tired of both squirrels digging up newly planted seeds, and the cabbage moths swooping in to lay their eggs. Now the raised bed protects all the Brassica crops I planted in the spring throughout the summer months. I think this will be my way of growing these crops moving forward. I’ll just made sure I don’t plant anything that needs to be pollinated. I look forward to getting some tips from Niki’s upcoming book, Growing Under Cover.

Purple Moon kale eaten by a cabbage worm

I planted some seeds for a new variety called Purple Moon in my A-frame raised bed. Soon there were a couple of small leaves on each seedling. Then one day I came out to water, and a cabbage worm had defoliated both seedlings since the day before!

Harvesting kale

Like lettuce, kale falls into that cut-and-come-again category. You don’t have to pull the whole plant or wait until it’s “ready.” You can keep harvesting the outer leaves at the base of the stem with scissors (I use my herb and veggie shears), and the plant will continue to grow new leaves in the centre of the plant.

Baby kale is a delicious salad green. And it may sound a bit nutty to massage your greens, but I will say that massaging kale leaves—especially the bigger ones—works to make them much more tender and palatable (and I think digestible) when eaten raw.

How to grow kale—and overwinter it for a second season

Many gardeners grow kale as an annual, but it’s actually a biennial. I didn’t realize this when I first was learning how to grow kale. Depending on where you live, kale can overwinter. It also doesn’t mind the cooler temperatures and in the fall, it can taste even sweeter after a frost.

Generally, to overwinter kale, you might want to cover it or plant in a protected area. Living under an escarpment, I’m in a bit of a protected zone, so I once had a kale plant live to be about three years old without winter protection! The leaves died back in fall, but came back in spring.

a kale plant in its third season

A few years ago, one of my kale plants came back three years in a row. This photo was taken the second time it overwintered. The stalks were like tree bark! Unfortunately, in its third spring, a hard frost in April did it in.

Besides my raised beds, I have grown kale along the side of my front garden. The cement provided a bit of warmth and protected my crop, but I also covered it in floating row cover for winter protection.

overwintered kale protected by floating row cover

My overwintered kale in early spring. I was harvesting the tender young leaves when there was still snow on the ground!

The new growth slowed considerably, but I was harvesting kale on winter days. Then in the spring, the plant started to become productive once more before growing flowers.

kale flowers

If you allow your kale to bloom, it will produce these lovely edible yellow flowers that the bees love!

In its second year, a kale plant grows really lovely yellow flowers that attract bees. If you don’t want to wait for the flowers to bloom, the unopened buds taste like broccoli. Simply pinch them off and add them to salads and stir fries. The flowers are edible, too—toss them in your salad for an ornamental topping.

kale buds

Kale buds, aka kale raab or napini, taste a bit like broccoli. Harvest some to eat and allow the rest to flower.

How to grow kale to save the seeds

Saving seeds is a really great cost-effective way to garden. And it’s a great way to save your favourite flavours that you’ve grown. Once your kale flowers, it will produce long seed pods. You can let these dry out in the garden, but a person I follow on Instagram (whose account I’ll link to once I remember who it was!), hangs her seeds to dry, like you would a bunch of herbs. I think I’ll try that this year!

What’s your favourite type of kale?

Related Posts

3 Responses to How to grow kale: Tips for planting, preventing pests, and harvesting healthy plants

  1. Leah says:

    I really want to save the kale seeds, but I am in zone 5 where has extremely cold winter. My kales always died away in late fall. Is there a way to survive kale through the harsh winter, so next year, the plants will produce flowers to seeds?
    By the way, I might try to dig whole kale out during the fall season and leave it in the garage, is it feasible? If yes, do I need to water it? What temperature should be ok to save the plant?
    Thank you.

    • Matt says:

      I’m in zone 5b and many but not all of my kale survived the winter under plastic (mini hoop house in a raised bed). I lifted the plastic and watered maybe 3-4 times during the winter. I conlcude that they can survive the cold but will break apart due to wind, snow, etc if not covered. I pulled the plants around june 15 and let the seed pods dry and used this for seed.

  2. Tara Nolan says:

    Hi Leah, Last winter some of my kale plants, planted against a stone garden wall survived under floating row cover. These are the ones that bloomed for me this past spring. You can plant in an unheated greenhouse, but a garage may work if there are windows and the plant will get some light.

Leave a Reply

Your email address will not be published. Required fields are marked *