Kale is one of my favorite leafy greens to grow each fall and spring in my vegetable garden. I love using it in smoothies, soups and salads. Here are some tips on how to grow organic kale in your garden.
Why Grow Kale?
Kale is super easy to grow and gives you a harvest every week during the growing season. You can step outside and grab a couple leaves for your morning smoothie or salad bowl. You can make your own kale chips or toss some leaves into a hearty soup to add more nutrients. When I say more nutrients, I mean more. Kale is considered one of the healthiest vegetables on the planet. Every leaf—whether it’s curled or bumpy like a reptile’s skin—is chock-full of vitamins and minerals. This might seem unnecessary to mention after that, but the plants themselves are also just really beautiful.
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THE BEST VARIETIES OF KALE TO GROW
These different varieties are winners in both the flavor and ease of growing departments:
- Dwarf blue curled kale – Blue curled kale has beautiful blue-green leaves with frilled edges. It’s super hardy and can overwinter in all but the coldest climates.
- Dinosaur kale – Dinosaur kale—also called black Tuscan kale and Lacinato kale—is a super fun variety to grow thanks to its dark-green leaves with their bumpy, almost-reptilian texture. It’s the texture that makes this type of kale frost-tolerant.
- Red Russian kale – This kale variety produces leaves that are sweeter than the others. The leaves look a bit like common oak tree leaves and feature beautiful reddish purple veins.
IS KALE PERENNIAL?
Kale is technically a biennial plant, but it’s often grown as an annual in colder climates. Kale can handle light frost really well. In fact, a little bit of frost actually makes the leaves taste sweeter. Hard frosts and extreme cold weather will eventually kill kale plants, though different varieties of kale have different levels of tolerance to frost and snow.
The nice thing about biennial plants is that they’re usually pretty low maintenance. Kale wants to make it to its second year in the garden so that it can produce seeds for the future. Some plants will put up with hot weather (as long as they’re kept well-watered). Less heat-resistant varieties will bolt (or go to seed) if it gets too hot in the summertime.
WHEN TO PLANT KALE SEEDS
Kale thrives when the temperatures are between 50°F and 75°F. Even though kale can grow when it’s much colder and much warmer, it’s best to start seeds or transplant kale seedlings to the garden when it’s nice and cool, just the way kale likes it. I typically start kale by seed indoors so that I can maximize the time kale plants have in cool weather.
In the spring, you can direct sow kale seeds outdoors a couple weeks before you last frost date. Soil should be workable and above 45°F. If you want to get a head start on your kale growing season, you can start kale seeds indoors about 4 to 6 weeks before your final frost date.
In the fall, you can direct sow kale outdoors as soon as your temps are dropping. If you’re ready to plant your fall crop and it’s still above 85°F, either plant it in a spot with partial shade from a taller plant already established in your garden or use a shade cloth. If you’d like to start kale seeds indoors, the best time is about 12 to 14 weeks before your first fall frost.
WHERE TO PLANT KALE
If you don’t have raised beds, you can grow kale in a large pot or container at least 12 inches deep. I recommend sticking with dwarf kale varieties if you opt for a container. Make sure the container you choose has at least one good drainage hole to allow excess water to leave (cover this hole with burlap or mesh to prevent soil from draining out).
I like gardening in terracotta pots to better regulate soil moisture. Even so, you’ll need to check on the soil frequently since containers dry out quicker than raised beds and in-ground gardens.
Kale needs a spot that receives at least 4 hours of sun per day. You’ll be able to harvest more leaves if you can provide 6 or more hours.
The Best Soil for Kale
Kale loves well-drained soil that’s rich in organic matter. If you’re growing kale in a raised bed, add some compost to the soil surface before you sow seeds or transplant young plants. If you’re growing kale in a container, fill your container with equal parts compost and organic potting soil. (It’s a bit on the pricier side, but I really love the Ocean Forest potting soil from FoxFarm.)
HOW TO PLANT KALE SEEDS IN 3 EASY STEPS
Kale is easy to grow from seed. Check out our indoor seed starting guide if you’re new to starting seeds indoors.
Follow these three steps to sow kale seeds.
Prepare your growing medium for planting. If you’re direct seeding, add a 2- to 3-inch layer of fresh compost to the top of the planting area. If you’re starting seeds indoors, fill your seed trays to the top with pre-moistened seed starting mix.
Use a dibber or a chopstick to make shallow holes in the soil or in the center of each seed starting cell. Kale seeds only need to be planted ¼” deep, which is not very deep at all. Do your best to place only one seed in each planting hole. If you’re direct sowing, go ahead and space your kale plants about 9 to 12 inches apart so they’ll have plenty of room to grow to their full and glorious potential.
Water the planting area gently. If you’re starting seeds indoors, I recommend using a water bottle to gently spray water on the soil surface and then also watering from the bottom of the seed tray to avoid displacing seeds. Your goal is to maintain consistent moisture until your seeds germinate. You should start to see little green shoots in 5 to 10 days. Turn your grow lights on as soon as you see signs of sprouting if you’re growing indoors.
HOW TO CARE FOR KALE PLANTS
Young plants need a little more care than established plants. I recommend covering newly planted kale with garden mesh cloth to prevent pests from attacking the tender leaves while they’re most tempting. You’ll also want to keep kale seedlings under shade cloth or place them in a shadier spot to protect them on hot days.
Let’s look at a couple tips and tricks to keep kale plants happy and healthy.
Thin kale seedlings if needed
How Many Kale Plants Can you Grow Per Square Foot?
Kale plants grow to be pretty large, so I recommend only growing one kale plant per square foot. If you’re growing in a raised garden bed, you can grow smaller plants like lettuce, spinach, herbs, and low-growing flowers around the base of kale. Make sure you harvest lower leaves and check for pests frequently if you’re planting close together like this.
Cover kale plants before a hard freeze
Water kale plants regularly
Keep the soil evenly moist for your leafy greens. Water regularly by hand or a drip irrigation system. If you’re using a hose or watering can, make sure to aim your water at the roots of the plant instead of the leaves to prevent disease.
Add compost around the base of kale plants every quarter
If you start off with really great garden soil, you don’t need to worry too much about adding extra nutrients. I like to just push some finished compost around the base of individual plants every three or four months. If you notice that kale leaves are looking yellow, you can add a nitrogen-heavy fertilizer.
The Best Fertilizer for Kale
When growing leafy greens, you want to focus on fertilizers high in nitrogen to promote healthy leaf growth. My favorite fertilizers for kale is MicroLife’s Ocean Harvest or Fox Farms Grow Big. You can reapply every 2 to 4 weeks during the growing season.
Protect kale leaves from pests
Kale is a member of the cabbage family, and unfortunately, being super attractive to pests is a family trait. Like I said, you can prevent pest issues in the first place by covering your garden with garden mesh the day you plant kale.
What are Common Kale Pests?
Kale is so enticing it draws quite the pest crowd. You might find anything from cabbage worms and cabbage loopers (little green caterpillars) to aphids. If your caterpillar issue has become out of hand, use organic measures like Bt spray (bacillus thuringiensis) to handle them. For aphids, try insecticidal soap or bio insecticide. (Learn more about dealing with aphids.)
HOW LONG DOES KALE TAKE TO GROW?
Kale grows relatively slowly for a leafy green but fast for a vegetable. You can actually begin to harvest baby greens about 21 days after planting, when the plant is just a couple inches tall. I recommend waiting a little longer to take your first leaves so that the plant has a longer time to get established. Plants should be about a foot tall or so in 55 to 80 days.
HOW TO HARVEST KALE LEAVES
Whenever you harvest from a kale plant, take the oldest leaves first (these are the lower, outer leaves). Leave young leaves to continue growing. (New leaves form from the center of the plant.)
Avoid taking more than a third of the leaves from any one plant within the span of a week. Harvesting individual leaves this way tells the plant to keep producing more nutritious leaves for you. That’s how you get continuous harvests from a couple of plants!
I like to gently twist each leaf away from the plant to snap the stem at the base, but you can also use a clean pair of scissors or needle nose pruners.
Enjoy Your Homegrown Kale Leaves!
Garden-fresh kale leaves are delicious in salads, stir-fries, smoothies, and winter soups.
If you’re a leafy green fan, you might have just met your new favorite plant to grow in a vegetable garden! Let us know if you have any questions in the comments below.