Zone 4 · September · 1 weeks before first frost
What to plant in September in Zone 4
Typical last frost in zone 4 is around May 15, and first frost around Sep 25. Autumn sowing closes. Cold zones are ending their season; warm zones are entering the best month of their year.
Start indoors this month
Seed trays indoors, under a light or in the brightest window you have. These are slow crops that need a head start on the season.
Nothing in our dataset needs an indoor start this month in this zone.
Set out into the final container
Transplants go into the pot they will finish in. Hardening them off for four to five days first prevents most transplant shock.
No transplanting window is open this month here.
Direct sow
Sow straight into the final pot. These crops resent root disturbance, and transplanting them usually costs more time than it saves.
No direct-sowing window this month in this zone.
Sow for autumn
A second sowing timed backwards from first frost. Fewer pests, less watering, and better flavour in most cool crops.
- Radish — window Aug 14 – Sep 4 (1 gal, 6" deep)
Harvesting this month
- Hot Pepper — harvest from Aug 17 (3 gal, 12" deep)
Not this month
- Cherry Tomato — next window opens in April. Starting it now means 7 months of impatient waiting, or a plant that stalls.
- Loose-leaf Lettuce — next window opens in April. Starting it now means 7 months of impatient waiting, or a plant that stalls.
- Basil — next window opens in April. Starting it now means 7 months of impatient waiting, or a plant that stalls.
Zone 4 at a glance
Zone 4 runs about 110–120 frost-free days. The real risk is a late frost in mid-May, not a cold summer, so the temptation to plant out early is the main mistake here.
Next and previous
August in zone 4 · —