What to Plant in April in Zone 3

Begin the hardening-off schedule for anything started under lights

Onion and leek starts from February and any brassica transplants from March need 7 to 10 days outside before they go into open ground for good. Set trays outdoors in a shaded, wind-sheltered spot for 2 hours the first day, and add an hour a day until they are outside full time.

Watch leaf color as your guide, not just the count of days. Leaves that bleach pale or curl under direct sun mean you moved too fast, and the fix is simply to pull trays back to part shade for 2 more days before trying again.

Cabbage, broccoli, and the early alliums are on their last window

Cabbage, broccoli, cauliflower, and bulb onions all show up as a last chance this month, meaning any transplant not in the ground by month's end is racing a shortened harvest. These crops size up in cool weather, and cool weather here runs out fast once summer heat arrives.

Get transplants in during the first half of the month if soil allows working it without clumping in your hand. A handful of soil that crumbles apart rather than balling up is dry enough to dig without compacting the bed.

Direct-seed the root crops while soil is still cool

Carrot, beet, radish, and turnip seed all hit their germination sweet spot between 55 and 70 degrees, a range Zone 3 soil climbs into as this month wears on. Sow radish and turnip thickly since both germinate fast, often within 5 to 7 days, and thin carrots and beets to 2 inches apart once true leaves appear.