Kale is one of the few vegetables that gets better when the weather turns cold. Most gardeners have heard this, but fewer understand what is actually happening: when temperatures drop below freezing, the plant converts starches in the leaves to sugars as a kind of cellular antifreeze. The result is a kale leaf in November that is noticeably sweeter and less bitter than the same variety harvested in August. This is not folklore — it is measurable biochemistry, and it is the reason serious kale growers plant for fall.
The spring crop tends to be productive but short-lived. Kale at your will give you good leaves through May and June, but as soon as summer heat arrives, the plants often or become tough and bitter. Aphids and cabbage worms are also more aggressive in warm weather. A spring planting can be worth it if you want early greens, but the fall crop is the one that will keep producing into December or January in most climates, sometimes longer.
For a fall harvest, start seeds indoors about six weeks before your first expected frost, or about ten to twelve weeks before that . The plants need time to size up before the days get short, but they don't need to be mature — a half-grown kale plant will sit through light frosts and keep producing new leaves all winter. In many regions, kale will survive under snow and resume growth when the snow melts.
Cabbage worms are the main pest you will deal with. These are the small green caterpillars that chew irregular holes in the leaves — they are the larvae of the white cabbage butterfly you see fluttering around the garden in spring and summer. from transplant until the plants are well-established can prevent most of the damage, but if you see the butterflies, check the undersides of leaves every few days and pick off any eggs or small caterpillars. Bt spray is effective if the infestation gets ahead of you, but hand-picking usually keeps it manageable.
Harvest by taking the lower leaves first, leaving the growing tip intact. The plant will keep producing new leaves from the center as long as you don't strip it bare. A well-established kale plant can be harvested weekly for months. If a hard freeze below 20 degrees is forecast, harvest heavily the day before — the leaves will hold in the refrigerator for a week, and you may lose some to freeze damage if they are left on the plant.
In spring, when the overwintered plants start to bolt, let one or two go to seed if you have the space. The tall flower stalks will feed early bees, and the seed is viable — you can save it and sow your own fall crop the following year.
Varieties worth knowing
What can go wrong
Companions
How to propagate
Kale is primarily grown from seed, but established plants can also be propagated from stem cuttings rooted in water. Seed is the standard and easiest approach.
Harvest & keep
Cut-and-come-again — take outer leaves, let center grow. Flavor improves after frost.
- Refrigerator
- 7–10 days (unwashed, in a bag)
- Freeze
- blanch 2 minutes, freeze in bags 8–12 months
- Can
- pressure can only
- Dry
- dehydrate at 125°F for kale chips or powder
Strip the center rib before eating raw or salting for massaged kale salad.
How it grows where you live
Sources
- Growing kale in home gardens— University of Minnesota Extension
- Kale— Clemson Cooperative Extension HGIC
- Kale production— Penn State Extension
- AphidSoft, clustered insects on new growth causing curled leaves and sticky honeydew.
- Black RotV-shaped yellow lesions at brassica leaf margins with blackened veins inside — a bacterial disease that moves through the vascular system.
- Cabbage LooperRagged holes in brassica leaves made by a pale green caterpillar that loops its body as it moves.
- Cabbage MaggotBrassica transplants wilting and dying as white maggots tunnel through roots at or below the soil line.
- Imported CabbagewormRagged holes in brassica leaves with pale green caterpillars and green frass nearby.
- I have aphids on multiple plants — do I need to spray everything?Aphids tend to colonize plants under stress and naturally crash when beneficial insects find them — water sprays and patience are often more effective than pesticides.
- Why did my broccoli skip making a head and go straight to flowers?Broccoli bolts when it experiences heat or stress during head formation — once it starts flowering, the head is unsalvageable, but timing adjustments can prevent it next season.
- How do I deal with cabbage worms on my kale and other brassicas?Bt (Bacillus thuringiensis) spray applied to the leaf undersides is the most targeted control for cabbage worms — hand-picking and row cover are also effective without any spray at all.
- What causes tip burn on lettuce or brown inner leaves on cabbage and other greens?Tip burn on lettuce and internal browning on cabbage are caused by localized calcium deficiency in the fastest-growing inner tissue — the same mechanism as blossom end rot, but in leafy crops.
- Something is cutting off my seedlings at the base overnight — what is it?Cutworms — fat gray or brown caterpillars that live in the soil and feed at night — cut young stems at or just below the soil surface, and a simple collar around each stem can stop them.
Save seed from this plant
All brassicas cross wildly. Save seed from only one brassica per year unless you isolate.