10 Tips For Growing Kale in Pots or Containers
Kale, once a trendy superfood, is a nutrient-dense veggie everyone can cultivate. Get all the benefits of this easy-to-grow brassica no matter where you garden by growing in containers! In this article, gardening expert Danielle Sherwood gives you 10 tips for delicious container-grown kale.
Everyone should grow kale. A powerhouse leaf cabbage packed with nutrients, it’s a versatile crop that’s excellent in salads, smoothies, soups, and pasta (honestly, I put it in pretty much everything). It’s even a great snack when dried for chips!
Kale isn’t difficult to grow. It doesn’t mind being transplanted and sprouts right up from seed. Purchase a plant or seeds once, and you’ll always have it. This is a long-lived veggie that’s happy to reseed itself. Whether you have raised beds or only room for small containers, you can get kale to thrive for you, green thumb or not.
In this article, I’ll give you tips for growing tasty kale in containers. We’ll look at its ideal conditions and how to translate them for optimum output in your garden. Let’s get started!
First, Pick the Right Container
Kale can grow pretty large, but its roots don’t take up much room. It doesn’t mind a bit of crowding but grows best if given the right amount of space. Keep these considerations in mind when choosing a container:
Kale is a vigorous green that can grow 2-3 feet tall. If given enough space, the roots will grow 18-24 inches into the ground. That said, kale will still grow successfully in a container that’s just 18 inches across and 10+ inches deep.
If you want to plant several varieties or more than one plant, stick with larger containers or a raised bed.
Kale likes fertile, well-drained soil. Its roots will rot if the growing medium is too soggy. Make sure the container you choose has drainage holes, and if using a larger raised bed, amend heavy soil with compost and sand as needed so water can flow through freely.
My kale has been growing happily in raised beds for years. As a biennial, it has a two-year life cycle. In the first year, it develops lots of yummy leaves we love to eat.
In the 2nd year, it bolts quickly, forming a flowering stalk that produces seed for the next generation of baby sprouts. The flower stalk is also edible and tastes particularly sweet. You may have seen it sold as Kale Rabe or Napini.
Kale is easy to cultivate in raised beds or pots. If you have enough space, try Birdies Metal Raised Garden Beds. They’re made of tough galvanized steel and coated with food-safe paint. These are a great alternative to wood beds, which decay over time.
If you’re working with a smaller space or even just a patio, try Epic Grow Bags. They’re made of permeable felt, which aids in drainage and lets air flow to the roots. They give you the flexibility of moving to wherever’s convenient (i.e., a cooler, shady location for heat-hating kale).
Kale is pretty robust and will be happy in most containers, provided you plant it at the right time.
Plant at the Right Time
This will be the number one factor in your success with kale. It loathes heat. Once temperatures reach above 75℉, kale plants get cranky and bolt. Avoid planting during hot summer days. Like most brassicas, it enjoys the cold and will taste even sweeter (due to higher sugar content) after a frost.
Instead, direct seed kale in autumn, winter, or early spring, depending on your region’s climate. You can plant it as soon as soil temperatures reach 40℉.
It takes between 55-75 days to mature, so plan accordingly for your area. You can also plant seeds indoors or buy a start from the nursery and transplant it into your garden as soon as the weather is warm enough.
Choose the Right Site
Site your kale where it will get 6-8 hours of direct sun. This is the rule when temps are cool. If you want to keep kale going for as long as possible when the hot summer season begins, pick a spot that receives afternoon shade.
Plan for the mature size of the plant. Choose a spot where each kale plant can grow 1-2 feet wide. For ideal airflow, space them at least 12 inches apart.
That being said, I let mine reseed where they like and thin them down a bit to the best-looking seedlings. They grow well packed together but don’t achieve the size they would if given more space. When growing in pots, decide if you want lots of smaller plants or one large, vigorous one and space accordingly.
Give it Good Soil
Kale likes rich soil. It doesn’t mind a bit of acidity but prefers a neutral pH between 6.5-6.8.
To grow in a container, use a good-quality organic potting mix and enrich it with a layer of compost. If the soil is too heavy and doesn’t drain well, amend it with some perlite or horticultural sand to help water flow through.
Kale likes its soil to stay moist but not waterlogged. Retain some moisture and keep it cool by applying a topping of mulch, like wood chips or straw.
Choose The Right Variety
Kale is a versatile plant that comes in a few different textures and flavor profiles. They can also be ornamental. I plant some varieties just because they have such pretty colors and structures.
If you need some additional ideas, below are some of the kale varieties I recommend you try in your garden this season.
Also called Dinosaur Kale (probably because it has bumpy scales like reptile skin) and Tuscan Kale, this popular heirloom variety is a chef’s favorite.
The leaves are dark forest green to black and look impressive in the garden. They can be harvested as baby greens in as little as 3 weeks from seed.
Dwarf Blue Curled
The leaves of this variety are super frilly, with an interesting texture and blue-green color that beautify the veggie bed! Harvestable in 3 weeks, this one can overwinter and feed you all year down to zone 6. As a dwarf version, it’s perfect for growing in pots.
Red Russian Kale is a flat-leaf variety with striking purple stems and red-tinged foliage. This is an extremely attractive kale that is popular as a baby green (it is softer and has a sweeter taste than curly kale types). Grow it as a cut and come again crop.
One of the most colorful varieties, with densely ruffled maroon leaves that can darken to deep purple. It becomes more flavorful as temperatures drop and is even more cold-hardy than other types. This is a great choice for autumn planting in cold climates, as it’s known to keep going after a hard freeze.
Seed vs. Nursery-Grown Plants
I always plant my Kale from seed. It’s so easy to do and much cheaper than buying nursery plants. I direct sow into my raised bed in early spring once the soil can be worked, and I begin eating the baby greens within 3 weeks.
Kale seeds are pretty small. Sprinkle lightly on the surface, covering them with about ¼ inch of soil and patting down gently with your hand. Keep them moist and see sprouts in 7-10 days as long as temperatures reach 40 ℉.
Alternatively, you can skip seeding and buy a nursery-grown plant that may be ready to harvest right away. Plant it as deep as the nursery pot and try not to disturb the root ball. Water well and provide some shade for a few days to avoid shock.
Water the Right Amount
Kale doesn’t like to dry out too much, especially when the days get hotter. Keep it moist by watering at least an inch or two per week. Checking the soil frequently is even more important when growing in containers, as it dries more quickly than it would in-ground.
I water kale daily in the spring as we don’t get much rain. If you’re not sure when and how much to water, stick your finger into the soil. If more than the top couple of inches are dry, give it more water. If it’s still moist, below an inch or so, you can wait and check again the next day. Thirsty kale will wilt, while leaves turn yellow when the plant is overwatered.
Fertilize (or Don’t)
Since we love kale for its delicious green leaves, we can encourage foliage growth with amendments high in nitrogen. I find that a topping of compost on my raised beds is more than enough for a healthy kale crop.
If you want to boost your kale, feed it a veggie fertilizer high in nitrogen (the first number on the NPK listed on the bag) once a month, watering it well. Wait until plants have grown for a few weeks and are at least 5 inches high before fertilizing, as baby roots can get nitrogen burned (although this is far less common with organic fertilizers than it is with lab-derived variants).
Diligently Watch For Pests
When grown in the garden, Kale can succumb to many different types of pests. You can use natural methods to keep them away, but you should still be vigilant when looking for any pests that may cause damage to your plants.
While they don’t threaten the life of the plant, no one wants a mouthful of bugs while enjoying a salad. It’s never a good idea to spray edible plants with pesticides (even organic sprays aren’t always food safe, and they may damage beneficial insects).
Your best strategy for keeping aphids off your kale is to hose down the plants early in the morning to knock off all the aphids on each plant (be sure to give it a solid blast of water!). You might also consider growing companion plants that repel them and/or attract their predators.
Plant with chives, thyme, and rosemary to repel aphids and with yarrow and dill to attract aphid-eating ladybugs, lacewings, and hoverflies. You can also tolerate them in the garden and soak the leaves to remove them after harvesting.
You’ll recognize flea beetles as tiny, shiny black insects that munch small holes in the kale leaves. Their big back legs help them jump when disturbed.
They have some of the same predators as aphids and benefit from companion planting. If they are a pervasive problem in your garden, buy a floating row cover and cover your kale as a preventative.
Cabbage worms look like little green caterpillars and can usually be found on leaf undersides, where they munch raggedy holes and sometimes completely skeletonize kale, leaving only the veins.
While they come in several species, the most common adult form is the cabbage white butterfly, which is small and white with two black spots. Check for small orange eggs under the leaves if you spot one fluttering around your kale. You can scrape them off or dispose of the leaf before they hatch.
Cabbage worms are easy to remove manually. Just pick them off and drop them into a jar of soapy water. Row cover is a useful preventative.
Use crop rotation to avoid planting kale in the same spot of a previous infestation since the pupa overwinters in the soil. Encourage the presence of parasitic wasps, who love to eat cabbage worms, with plants that produce umbel-shaped flowers like dill and cilantro.
Now for the good stuff. You want to eat all that hard-earned kale! You can harvest it a few different ways.
Kale is most tender as a baby green. To harvest these:
- Wait until the plant is at least 3 weeks old.
- Harvest the lower, outermost leaves first.
- Leave the smallest 4-6 leaves in the center to keep growing.
- Cut leaves right at the stem with sharp scissors (or pinch them off with your fingers)
- You can harvest again in a week or so, taking the largest mature leaves each time.
You can also harvest larger leaves for use in hearty salads, cooked dishes, and pesto:
- Wait until leaves are at least the size of your palm. These will retain their structure better for cooking.
- If you want to use the whole plant, clip the entire leafy stalk right below the soil level.
- Wash well (I like to plunge and swirl mine around in a big bowl of water so any little bugs will dislodge)
Once temperatures get hot, your kale will bolt. You can leave the flowers to reseed or eat them stalk and all. Cut off the stem right at the soil level, leaving the roots to decompose and add nutrients for your next planting.
Growing kale is pretty fool-proof if you keep in mind that it likes cool weather. It’s a hearty and flavorful brassica that keeps on giving until the weather gets too hot. Save the seeds or let it seed itself for an endless supply of nutrient-rich veggies.
Planting kale in containers is convenient and helps you extend the growing season by moving it to cool, shady areas as temperatures rise. For your best kale season ever, remember to cut down on pest pressure via row covers and companion planting, keep the soil moist, and enjoy munching those leafy greens!