What to plant in April in zone 6, before and after the last frost

April in zone 6 is the month the last frost passes, usually around April 21. Before that, plant the hardy crops: peas, potatoes, onions, lettuce, spinach and the cabbage family. After it, start the fast summer crops indoors so they’re ready to go out in May.

Tomatoes, peppers and eggplant stay inside in April. A warm week tempts everyone, but a frost in late April is still common, and cold nights stall them even without one.

Sow and plant outside

Crop	What to do	When in April
Peas	Sow outdoors or plant out	All month
Fava beans	Sow outdoors	All month
Potatoes	Plant seed potatoes	All month
Onions	Sow or plant sets	Until mid-April
Leeks	Sow outdoors or plant out	All month
Carrots	Sow outdoors	All month
Beets and Swiss chard	Sow outdoors or plant out	All month
Lettuce, spinach, arugula	Sow outdoors or plant out	All month
Radishes and turnips	Sow outdoors	All month
Parsnips	Sow outdoors	All month
Cabbage, broccoli, cauliflower	Plant out transplants	All month
Kale	Sow outdoors or plant out	All month
Cilantro	Sow outdoors	From early April
Strawberries	Plant	All month
Asparagus crowns	Plant	Early April

All of these are hardy enough for a light frost once hardened off. Keep row cover handy for nights forecast near freezing, especially over new transplants and potato shoots.

Start indoors

Crop	When in April	Goes outside
Basil	All month	Early May to mid-June
Zucchini, cucumbers, winter squash	Mid to late April	May
Sweet corn	Mid to late April	May
Green beans	Mid to late April	Early May to early June
Melons	Mid to late April	Mid-May onwards
Zinnias, sunflowers	All month	After the last frost

These grow fast, so three or four weeks indoors is plenty. Sow them in individual pots to avoid disturbing the roots, or wait and sow them straight into warm soil in May.

If your tomatoes and peppers are already up, move them into bigger pots this month, and start hardening them off for a few hours on warm days towards the end of April.

Getting the timing right

These dates assume a last frost around April 21 and a first fall frost around October 17, typical for USDA zone 6. Zones come from winter lows, not frost dates, so your own last frost may be a week or two either side. Higher, colder sites run later. Cities and gardens near large bodies of water often run earlier.

Jobs for April

• Watch the forecast. A clear, still night after a warm day is when frost strikes.
• Harden off transplants for a week before planting: a few hours outside at first, building up to a full day and night.
• Sow little and often. A short row of lettuce, radishes and spinach every two weeks beats one big sowing.
• Mulch strawberries and garlic to keep moisture in and weeds down as the soil warms.

Already picking: overwintered spinach and kale, lettuce, radishes, the first asparagus and rhubarb.

For timing peppers, see peppers in zone 6. The sowing calendar shows every crop with zone 6 dates when you pick it from the frost menu.