Vegetable · Brassicaceae
Kale
Brassica oleracea Acephala Group
Plant it once and keep pulling tender leaves from spring right through winter, because kale just keeps coming.
Full sun
Every 3–7 days
55–75 days
USDA 2–11
Overview
Kale is the leafy cabbage relative that skips the tight head and throws up a loose, open rosette you pick from as it climbs. It runs through a whole spread of looks, from the ruffled blue-green curls of the standard types to the long, puckered straps of the Italian heirlooms. Best of all, it stands as one of the easiest vegetables a beginner can grow, so early wins come fast.
This is a cool-season crop that hits full stride in the mild weather of spring and fall, and it laughs off frost that would drop a tomato overnight. The cold actually plays on your side here, since a hard chill drives the leaves sweeter and milder rather than tougher.
Hand kale full sun, steady moisture, and rich soil, and a single planting keeps cranking out food for months. Snap off the outer leaves whenever you want them and leave the center to power on, so the harvest rolls out over weeks instead of ending all at once.
Care
The short version: kale runs on full sun and rich, evenly moist soil with about an inch to an inch and a half of water a week. Feed it through the season, plant it for spring and then again for fall, and grab the lower leaves as you go.
Light
Kale craves full sun, at least 6 hours a day, to bulk up full and leafy. It gets by in partial shade where summer heat runs hot, but deep shade drops you to thin, slow plants with sparse leaves.
Water
Keep the soil evenly moist with about 1 to 1.5 inches of water a week. That steady moisture is what drives tender, mild leaves instead of tough, bitter ones, so lay down mulch to lock the water in.
Soil
Plant kale in fertile, well-drained loam loaded with organic matter. A pH of 6.0 to 7.5 hits the sweet spot, and pushing acidic soil toward the top of that range also helps beat back clubroot.
Temperature
This cool-season crop thrives across 10°F to 81°F (-12°C to 27°C). It takes hard frost in stride, and the cold even sweetens the leaves, while real summer heat is what turns them bitter and fires the plant into bolting.
Humidity
Kale asks nothing special of humidity, so skip chasing a number. Good airflow does the heavy lifting, since crowded, damp leaves are exactly what pull in the aphids and diseases that hit brassicas.
Feeding
Work a balanced fertilizer into the bed at planting from a soil test, then side-dress with nitrogen about 4 to 6 weeks on to keep the leaves rolling. Go easy on the nitrogen, though, or the soft, lush growth reels in aphids.
Pruning
Kale skips real pruning entirely. Harvest the lower, outer leaves once they are big but still tender, leave the central growing point alone so the plant keeps producing, and snap off any leaf that yellows or gets chewed.
Size & spacing
Plants shoot up to 1 to 3 feet (30 to 100 cm) tall and spread nearly as wide. Set them 12 to 18 inches (30 to 45 cm) apart so air rips through freely and each one has room to fill out.
When to plant
Kale is built for cool weather and a long, rewarding season. Sow it in early spring for an early summer cutting, then sow again in midsummer for a fall and winter crop that just keeps sweetening as the cold rolls in.
Northern hemisphere
Southern hemisphere
Typical months for a temperate climate: start earlier in warm zones, later where spring frosts linger.
- Sow: Start seed indoors 6-8 weeks before the last spring frost; for a fall crop, start in mid-summer
- Plant: Set transplants out 3-4 weeks before the last spring frost, or direct sow as soon as soil is workable; sow again in mid- to late summer for fall harvest
- Harvest: Harvest spring sowings in late spring to early summer before heat turns leaves bitter; harvest fall crops into winter - flavor sweetens after light frosts
Hardiness
USDA hardiness zones: 2–11
Temperature: down to -46°C
Troubleshooting
Almost all of kale's troubles land on the leaves, right out in the open where the chewing pests and sap-suckers work. Flip the leaves and scan the undersides often, and you catch problems while they are small. Match what you spot below, then move on it before it spreads.
Plants wilting and stunted with swollen, distorted roots
When a plant flags in the afternoon, yellows, and quits growing, dig it up and go straight for the roots. Thick, club-shaped galls spell clubroot, a soilborne disease that stays put once it lands and will not be cured, while tunneled roots hiding small white grubs finger cabbage root maggot instead. Yank and destroy anything infected rather than composting it, march the brassicas to fresh ground, and lime the old bed toward pH 7.0 or above.
Fix:
- Remove and destroy infected plants; do not compost them
- There is no cure in infested soil - grow brassicas elsewhere
Ragged holes chewed through the leaves
Ragged holes and green droppings give away cabbageworms and cabbage loopers, often working alongside diamondback moth larvae. Pluck the caterpillars off by hand, and bring in Bt or spinosad to knock down any that keep hatching. Get ahead of the whole thing by draping a floating row cover over the plants at transplanting, which shuts the egg-laying moths out from day one.
Fix:
- Handpick caterpillars
- Apply Bacillus thuringiensis (Bt) or spinosad according to label directions
Curled, sticky leaves with clusters of small insects
Waxy gray-green clusters packed into the leaf folds mark cabbage aphids, and clearing them is quick work. Blast them loose with a hard jet of water, then chase them down with insecticidal soap right on the undersides where they cling. Better still, let the lady beetles and parasitic wasps stick around, because they hunt the next wave for you.
Fix:
- Dislodge with a strong spray of water
- Apply insecticidal soap, covering leaf undersides thoroughly
- Encourage natural enemies such as lady beetles and parasitic wasps
Tiny shothole pits peppering young leaves
Those little round pits announce flea beetles, shiny black specks that spring off the leaf the instant a hand moves in. They mostly go after seedlings in warm, dry spring weather and rarely slow down a plant that is charging along. Keep the young ones under row cover and driving hard, and they simply grow right past the nibbles.
Fix:
- Protect young plants with row cover
- Apply a labeled insecticide if damage is severe on seedlings
Toxicity
Kale is a food crop through and through, safe for people and for the animals working the garden edges. There is no toxin in play, so the one real note is moderation: piling on very large amounts of the raw brassica foliage day after day can act as a mild goitrogen for grazing livestock.
Safe for
People · Cats · Dogs · Horses · Rabbits · Livestock · Birds
Cats None
Let a curious cat swipe a leaf, because kale carries no toxin for them. Wolf down a big pile of the raw stuff and the worst that turns up is a bit of gas or a loose stool, then it passes.
Dogs None
Kale is safe for dogs and jumps into all kinds of homemade bowls. Just dish it out in small portions, since a sudden heap of the raw leaves can leave a pup gassy or a touch queasy.
Horses Safe
Kale won't poison a horse, so hand it over now and then with no worry. Keep it an occasional extra rather than a staple, because a steady run of brassica greens acts as a mild goitrogen over time.
Rabbits Safe
Rabbits tuck into kale happily as one green among several. Ease it in slowly and keep the servings modest so it never elbows aside the hay their gut runs on.
Livestock Safe
Cattle, goats, and sheep graze kale with gusto, and growers plant it on purpose as forage. Load them up on the foliage day after day, though, and it works as a goitrogen, so mix it into a wider ration.
Birds Safe
Chickens and other birds dive right into kale, leaves and stalk together. It hands them a healthy green treat with no toxic parts to dodge.
People Safe
Kale is a powerhouse everyday vegetable, brilliant raw in a salad or cooked. Give it a quick rinse first, same as any leafy green straight from the garden.
Like other brassicas, kale contains goitrogenic compounds; very large quantities of raw kale fed routinely could affect thyroid function or cause digestive gas in pets and livestock - a moderation note, not a poisoning risk.
Varieties
Kale runs to dozens of cultivars, but a handful keep charging back into gardens and onto extension lists year after year. These are the ones worth grabbing by name.
Lacinato (Tuscan, Dinosaur)
This Italian heirloom shows off narrow, dark blue-green, heavily puckered strap-like leaves, and UF/IFAS points to it for Florida gardens.
Winterbor
Winterbor powers through hard cold as a very cold-hardy hybrid, shooting up tall and productive with finely curled blue-green leaves.
Redbor
Redbor brings deep red-purple curls that richen as the weather cools, earning a spot in the flower bed every bit as much as the kitchen.
Red Russian
Red Russian ranks among the sweetest types, offering up tender, flat, toothed gray-green leaves laced with purple veins and stems.
Vates Dwarf Blue Curled
Vates Dwarf Blue Curled stays compact and low, shrugs off bolting, and has held its spot as an extension favorite for ages.
Companions
Kale grows best beside aromatic herbs and alliums that throw pests off the scent, and worst beside its brassica cousins, which trade the same diseases and pests back and forth.
Plant near
Dill: Aromatic herb whose flowers attract parasitic wasps and other beneficial insects that prey on cabbageworm and aphid pests of brassicas
Onion: Aromatic allium interplanted with brassicas may help confuse or deter common insect pests and competes little for space
Beet: Compatible cool-season root crop that occupies a different root zone and shares similar growing conditions without hosting brassica pests
Keep apart
Cabbage and other brassicas: Crops in the same family share pests and diseases (cabbageworms, aphids, clubroot, black rot); grouping them in the same bed and skipping rotation lets problems build up
Strawberry: Traditionally listed as a poor neighbor for brassicas; the perennial bed also conflicts with the crop rotation brassicas need
How to propagate
Kale is one of the easiest vegetables to launch, springing up readily from seed sown straight in the ground or raised as transplants.
SeedEasy
Direct sow in early spring as soon as soil can be worked and again in mid- to late summer for a fall crop, or start indoors 6-8 weeks before the last spring frost · Seed germinates in about 5-10 days; transplants reach setting-out size in 4-6 weeks and plants mature in roughly 55-75 days
Kale takes off from seed with almost no effort, whether you sow it right in the bed or raise it as transplants. Sow the first round in early spring the moment the soil can be worked, sow again in mid- to late summer for a fall crop, or jump-start it indoors 6 to 8 weeks before the last frost. Drop the seed 1/4 to 3/4 inch deep and give plants 12 to 18 inches to stretch. Seedlings burst up in about 5 to 10 days, hit transplant size in 4 to 6 weeks, and mature in roughly 55 to 75 days.
Myths
Frost ruins kale, so the crop has to wrap up before cold weather arrives.
Kale ranks among the toughest vegetables going, brushing off frost and light freezes that flatten tender crops. The flavor even sweetens after a frost as the plant flips its starches into sugar. Fall and winter are when kale tastes its absolute best.
You have to pull the whole kale plant to harvest it.
Grab the large lower leaves, leave the central growing point alone, and the plant keeps pumping out fresh ones. That turns one plant into weeks or months of repeat picking instead of a single cutting.