What to Plant in September in Zone 3: Last Call Before Frost
In USDA zone 3, September is last-call, not a planting month. Fast radishes or arugula may still fit. Then cover crops. Skip garlic and warm crops.
Published by ThriveThyme
September Zone 3 September zone 3 fall planting
What to Plant in September in Zone 3
In USDA zone 3, September is last-call, not a planting month. First frost often arrives in September in many zone 3 gardens, but yards vary. Most long-season fall crops are too late from seed. Fast radishes, arugula, spinach, or lettuce may still finish if the catalog window is open and frost settings allow. Then sow cover crops on spent beds. Do not start tomatoes, peppers, or melons. Do not plant garlic in September.
Use My Garden frost settings or the zone 3 fall calendar and count backward. See What to plant now and warmer September zone 6 timing for contrast.
Sow These Only If Frost Allows
- Radishes and arugula: short crops. Catalog fall windows run about August 15 to September 30. Confirm several weeks remain before a hard freeze. Fall radishes, fall arugula.
- Spinach and lettuce: late from seed. Only if frost settings still show an open window. Fall spinach, fall lettuce.
- Kale, broccoli, cabbage: too late to seed for a fall head. Harvest what you transplanted earlier, or grow fast greens instead. Fall kale, fall broccoli, fall cabbage.
Cover Crops on Spent Beds
If a bed will not hold a short green crop, sow cover crops now. Oats and rye are the usual cold-zone choices. Time sowing against your first hard freeze. When to sow cover crops by zone.
Wait on Garlic
Do not plant garlic in September in zone 3. Cloves need cool soil later in fall. Order seed garlic now if you have not. Garlic by zone.
Next Steps
Check frost settings today. If weeks remain, sow a short row of radishes or arugula. Clear one spent bed for cover crop. Put garlic on the list for later fall.