In zone 4, plant kale outside around April 18, about four weeks before your last spring frost, as seed or transplants. For a fall crop, which tastes even better after frost, the last sowing date is about July 17.
Kale dates for your ZIP code
Planting times based on university extension guidance (UNH, Cornell, Purdue, Minnesota, Nebraska and UMass Extension). Frost dates from NOAA 1991–2020 U.S. Climate Normals, nearest weather station. Zones derived from the 2023 USDA Plant Hardiness Zone Map data (PRISM Climate Group, Oregon State University). This is not the official USDA Plant Hardiness Zone Map.
Kale timing in zone 4
| Task | When |
|---|---|
| Start indoors (optional) | March 7 – March 21 |
| Plant outside | April 18 |
| First harvest | June 12 – July 2 |
| Sow for fall by | July 17 |
| Thin seedlings | To 8–12 inches apart |
| Start fall transplants | Indoors in early summer |
| Harvest | Larger leaves as needed, well past the first frosts |
Most of zone 4 sees its last spring frost between May 11 and May 23 (typical May 16) and its first fall frost between September 21 and September 29 (typical September 25). Kale is very cold tolerant and keeps producing well past the first fall frosts. The tool above uses the weather station closest to your ZIP code.
Why kale is planted early and late
Kale is one of the most cold-tolerant vegetables. It handles frost, keeps producing well past the first fall frosts, and the cooler the weather, the better it tastes. That is why it goes out about four weeks before the last spring frost and is sown again in summer for fall.
Best kale varieties for zone 4
Kale is one of the hardiest crops you can grow in zone 4. Good choices include:
- Curly kale: Winterbor (very cold tolerant), Vates and Dwarf Siberian.
- Colorful kale: Redbor, in green and purple, and the Nagoya mix.
- Red Russian kale is tender and attractive, but in some northern areas it is especially prone to swede midge.
Choose eating varieties, not ornamental kale grown for garnish.
How to plant kale
- Sow seeds directly ¼–½ inch deep, or start transplants indoors about four weeks before planting out.
- Space rows 18–30 inches apart.
- Thin seedlings to 8–12 inches apart, or 4 inches for baby greens.
- Set transplants about 8 inches apart in rows 18 inches apart.
- Keep the soil evenly moist for tender leaves.
Zone 4 kale tips
- Sow early in spring, as soon as the soil can be worked, or start transplants indoors about four weeks ahead.
- Make fall your best crop. Sow about three months before your first frost. Cool weather sweetens the flavor until hard freezes stop growth.
- Harvest the big leaves. Pick the larger leaves and leave the small ones, and the plant keeps producing.
- Protect seedlings from pests. Flea beetles and cabbage worms do the most damage to young plants.
Harvesting kale
Pick leaves as soon as they reach a usable size, taking the larger ones and leaving the small ones to grow. You’ll get many harvests from the same plants. You can also cut the whole plant just above the soil. Leaves can be harvested even after they freeze.
Kale planting dates in nearby zones
See dates for every zone on the kale planting guide, or build a full schedule with the planting calendar.
Frequently asked questions
Is it too late to plant kale in zone 4 in May?
No. Kale is forgiving: a May sowing still grows, and you can sow again in summer for fall, by about July 17.
How late into fall can I harvest kale in zone 4?
Well past the first frosts. Kale keeps producing in cold weather and tastes sweeter, until hard freezes stop it.
Can kale handle frost?
Yes. Kale is very cold tolerant, and frost actually improves its flavor.
How do I harvest kale so it keeps growing?
Pick the larger leaves and leave the small ones in the center. The plant keeps producing new leaves.
Can I eat ornamental kale?
Grow eating varieties instead. Ornamental kale is bred for color and used mainly as a garnish.
Sources. Planting dates use the median frost dates of each USDA zone, calculated from NOAA climate data for every ZIP code in the zone.