Kale is probably the easiest crop you can grow in the Pacific Northwest. Our cool, mild climate is perfect for kale, which can easily become a year-round source of hipster-approved greens. However, like most cold hardy brassicas, kale tastes best when the weather turns chilly, so if you aren’t a major kale lover, grow this one for fall and winter harvesting.
Kale comes in many varieties and leaf shapes, colors and flavors, so this is a fun crop to play around with – and success is practically assured.
In this article, I’ll be referring mostly to kale, just because that’s what I typically grow and harvest. However, collard greens are grown like, and can be used like, kale. They have the advantage of being a bit more heat-tolerant, so if you are in a warmer microclimate or if summer is particularly hot, collards are a good choice.
What Kale Looks Like
Like all brassicas, kale seeds are small spheres, medium brown to black in color. The cotyledons (seed leaves) for both have a squatty, heart shape. Below: kale seeds, sprouts with seed leaves only, and seedlings showing the first true leaves.
Kale leaf shape and color is incredibly variable. If you think about the color and shape variety from “ornamental cabbages” that are sold in fall at garden centers, you have some sense of the diversity of leaf shape and color in kales.
Below, four examples of kale leaf shape diversity. In contrast, collard green leaves have a smoother, wider leaf shape. Color on collards varies from quite blueish to a more bright green. I’ve even seen a variegated variety.
- Common Name: Kale
- Latin Name: Brassica oleracea (Acephala Group)
- Family: Cabbage (Brassicaceae)
- Hardiness: Hardiness varies by cultivar; most varieties can take temps to 18 degrees. The most cold-tolerant types reportedly survive temperatures down to -15 degrees. (It doesn’t get that cold here so I can’t vouch for this.) All kale is typically hardy in the lowland Maritime Northwest with no or minimal protection.
- Lifecycle: Biennial, although in some conditions plants can go to seed their first growing season.
- Season: All, but flavor is best after plants have been exposed to frost, so this is an ideal fall/winter vegetable.
- Days to Maturity: About 21-30 days for baby leaves, 60 for full-size leaves.
- How Hard Is It To Grow? Very easy
Pacific Northwest Specific Tips and Timing
Conditions: Kale is an easy, rewarding crop in the Pacific Northwest. For best results try to give your kale full to nearly full sun, slightly acidic to neutral pH fertile soil, and consistent moisture. However, kale handles a part-sun location, and will tolerate a wider range of soil conditions than many garden vegetables.
Timing: If you start your kale plants indoor in late winter at the same time you’re starting broccoli and cabbage, these plants will be huge come fall, and will likely take you all the way through the next spring. However, summer sowing before mid-July for a fall harvest works fine too.
Season Extension: In higher-elevation regions or during the occasional Arctic blast, row cover or cloching will help your kale make it through the winter.
Kale Seed Info
Typical Seed Life: 4 years, or more if kept consistently cold and dry.
Germination: Kale seed of good vigor should germinate very rapidly, in no more than 4 to 6 days in soil from 50 to 60 degrees F.
How To Plant Kale
Seeds or Starts? Either. Kale germinates well in cool soils, so indoor plantings aren’t really necessary. However, plant spacing is easier if you work from transplants, and starting indoors can help avoid slug and snail damage early in the season.
How Much To Plant: An omnivorous family of four will probably find that 3 – 4 full size plants will give them all the kale they really want. However, real greens lovers and gardeners looking for a large supply of homegrown wintertime greens might plant 4 times this much kale. Between about mid October and mid February your kale will be essentially static, so you should plan on going into the winter with enough full-size plants to see you through whatever quantity of harvest you’ll want.
Starting Indoors: Sow a clump of 2-4 seeds in a pot with generous root room – I like 2-inch square pots. Keep soil temperature moderate – 50 to 60 degrees is plenty warm for strong kale germination, and a bit cooler is better earlier in the season since you’ll be transplanting into chilly soil. 16 hours on and 8 hours off under seed lights works well for growing most vegetables, and I’ve never had a problem with kale following that protocol. Thin to the strongest seedling before the kale starts begin to crowd each other.
Sowing Outside: Plant seeds shallowly, about 1/4-inch deep. For a baby leaf crop, scatter seeds over the soil surface and rake or water them in. For large plants, sow clumps of 4-6 seeds at least 12-inches apart in all directions. Thin to the stockist seedling once your kale is up and growing well and starting to crowd. Alternatively, sow seeds about an inch apart in rows 18 inches apart, and thin kale plants as they start to crowd.
Self-Sowing: If you allow Red Russian kale to go to seed, you’ll never have to plant it again and you’ll never be without it. I haven’t noticed the same tendency with other cultivars, but I can personally attest that Red Russian self-sows like crazy and is a wonderful kale-ful gift in the garden.
Kale’s Growing Needs
Sunlight: Adaptable. In the Pacific Northwest Kale does fine in full sun, but will tolerate part-sun conditions. Try for at least 4 to 5 hours of sunlight per day. In hot-weather climates, kale is best in part-sun, and especially appreciates afternoon shade. Consider collards if you are in a hot-summer climate. They are more heat tolerant and will perform better.
Soil Conditions: Average fertility garden soil with a pH of 6.5 to 7 is fine – although you’ll have more abundant and more tender leaves from rich soil high in humus.
Feeding: For the best growth and most abundant leaves, amend the soil where the kale will grow with compost and complete organic fertilizer (something like a 5-5-5). If leaf production slows during the growing season, side-dress kale with additional complete organic fertilizer.
Watering: Kale prefers consistent moisture. In the Pacific Northwest, I rarely need to water kale before about late June unless it is growing under a low tunnel. Once seasonal rains slow, deep watering about once a week is fine for mature plants; water a bit more frequently for plants that are just getting established, or if you see sign of water stress from your plants.
Red Russian Kale: My standard, because it self sows everywhere and is very reliable. Fairly tender, even at larger leaf sizes, this is a decent tasting kale but a bit stronger to my palate than Tuscan.
Red Chidori Kale: Not widely sold, this is still one of the tastiest kales I’ve ever grown. That’s odd, because it’s basically an ornamental type, with a low-growing rosette form. Very sweet after a frost, and gorgeous worked into an ornamental edible landscape
Tuscan Kale: Also called Lacinato, Black Kale, Nero di Toscana, Cavolo Nero, Black Palm, Dinosaur Kale and probably a dozen other things. This is the dark green, crinkly, narrow-leaved kale that became a darling of healthy eaters and fancy chefs everywhere in the early-oughts. A mild tasting kale, this one is great in soups, sauteed, or raw as a salad.
Winterbor Kale: Extremely cold tolerant, with very curly leaves. I personally prefer the flatter leaves of Red Russian or the moderate crinkles of Tuscan, but Winterbor is a great choice if you live in a colder region.
Vates Collards: I’m not a collard expert but I’ve grown Vates and found the leaves large, smooth, moderately tough and waxy, and excellent braised in the Southern style. Research tells me this is a good choice if you prefer to cut a few leaves at a time from a mature plant and allow the plant to continue growing.
Flash Collards: Flash is a popular hybrid said to be more tender than Vates, and a good choice if you want to cut the full plant for a harvest of slightly smaller but more tender leaves.
How To Harvest Kale
For baby kale, sow densely and cut swaths of leaves when plants are 3-4 inches tall with scissors. Hold clumps of leaves gently in one hand and snip about an inch above the soil line with the other hard. Leave the plants in the ground, they will regrow for another harvest.
For bunched kale leaves, cut or tug individual leaves from a mature plant downward from the stem. The leaf should separate cleanly from the stem. Select outer, lower mature leaves in good condition and allow the upper, center leaves to continue growing. A very mature kale plant can start to look like a miniature palm tree, with a long, tall, bare stem and a clump of leaves at the top. This is normal.
For whole-plant harvest of kale or (more often) collards, cut the teenage-sized or mature plant through the stem just above the soil level as you would with cabbage. Harvest before the plant starts to grow a distinct, thicker center stem.
Overwintered kale produces loads of kale florets in the spring. These unopened flower buds taste much like sprouting broccoli. More details here.
How to Cook and Eat Kale or Collards
Kale has a rugged, cabbagey flavor with a hint of bitterness. Some people think collard greens are milder and more tender. This may be especially true in hotter-weather climates, but from a culinary perspective these two leafy brassicas have far more in common than not.
Collards have a smoother, wider leaf, so if you are low-carb or otherwise looking for a green vegetable to substitute for flatbread or tortillas, collards are a superior option. Otherwise, collard greens can be used in any of the ways you’d use kale.
Kale can be eaten cooked or raw. Baby kale can be quite tender, but older leaves benefit from tenderizing through salting or massaging if they are going to be used in a salad. Kale is sweetest after it is kissed by frost, so harvests in late fall and early winter are often the best.
I love using kale in a salad – one of my favorite combinations is Tuscan kale paired with roasted sweet potatoes. The bitterness of the kale is complimented and balanced by the sweetness of the sweet potato. I often simply saute kale with garlic then finish with a squeeze of lemon or a splash of apple cider vinegar.
Kale is also a fantastic addition to soups, and pairs well with beans, sausage, and root vegetables. (Recipe: White Bean, Sausage and Cavolo Nero Kale Soup) It can be long-cooked and still retain a nice toothsomeness. Portuguese kale is particularly well-known as an ingredient in soups.
Kale and collards both braise extremely well, and any variation of braised greens or creamed greens can be made with either. Finally, kale sprouts – the tender florets of the kale plant – are a late winter or early spring treat very similar to sprouting broccoli or broccoli raab. Saute with garlic or roast for a delicious broccoli-like dish.
Kale’s Friends and Foes
Pests: All the standard brassica-family pests will bother kale, but typically not to the degree that they will bother more refined brassicas like cauliflower, cabbage, and broccoli.
In my garden, the only substantial pest problem I deal with is the grey woolly aphids that periodically congregate on the growing tips of the kale. These aphids grow rapidly into huge colonies which can distort the leaves and make a “clean” harvest extremely difficult. Collards with their thicker, waxier leaves are said to be less affected by both aphids and flea beetles.
Pests that may bother kale include:
- Aphids – a blast of water will dislodge aphids; a mild soap spray can be used for more severe infestations.
- Cutworms – homemade paper collars made from toilet paper tubes, paper cuts, or foam will prevent cutworms from chewing through seedling’s stems.
- Cabbageworms (More: The Cabbageworm Caterpillar in Your Garden: How To Control It)
- Flea beetles – use yellow sticky traps or a mild, organic insecticide to control.
- Cabbage root maggots – I’ve never had an issue with these on kale, but did lose an entire crop of broccoli from cabbage root maggot one year. Beneficial nematodes (The Steinernema feltiae strain) worked very well for me to control that pest.
- Slugs and snails – use traps, or apply Sluggo. (More: How to Identify and Control Four Common Garden Pests of the Pacific Northwest)
Diseases: I grow a lot of kale, and the only disease I run into is periodic powdery mildew. This typically hits older plants nearing the end of their life span, so rarely impacts my yields much.
That said, most brassica family diseases can impact kale, too. Probably the most serious disease to worry about is clubroot. Prevention is key, so do try to rotate your brassicas, including kale.
Companions: Nitrogen fixers like peas and beans grown vertically behind kale will help provide soil nutrition. Strongly aromatic herbs like basil, dill, and mint confuse and deter sucking-type pests that might bother kale. Garlic and onion are both excellent companions to kale, for the same pest-deterrent reason.
Antagonists: None I’m aware of.
One of my awesome Patrons loathes kale. I’m dedicating this post to her. Sorry Kat. <3