What to plant in March — zone 4a
Zone 4a averages its last spring frost around May 20 and its first fall frost around September 20. Everything below is timed from those two dates, so it stays useful whether you're planting for summer or for a fall harvest.
Dormant care
- Prune dormant fruit treesaround Mar 4
Prune apples, pears and peaches while fully dormant — open the center, remove crossing wood.
- Check season-extension geararound Mar 25
Patch row cover, cold frames and hoops now so a late freeze can't catch you unprepared.
Start indoors
- Start onions and leeks indoorsaround Mar 11
Alliums need 10-12 weeks under lights before they go out — the earliest sowing of the year.
- Onionaround Mar 11
10 weeks of indoor growth before your last frost (05-20). Match day-length to your latitude — long-day north of 37°, short-day south.
- Pepperaround Mar 25
8 weeks of indoor growth before your last frost (05-20). Pinch first flowers on transplants so the plant invests in roots before setting fruit.
- Parsleyaround Mar 25
8 weeks of indoor growth before your last frost (05-20). Soak seeds 24 hrs before sowing. Cut outer stems and it comes back for years in mild zones.
- Chivesaround Mar 25
8 weeks of indoor growth before your last frost (05-20). Divide the clump every 3 years — one plant becomes six with no effort.
Turn this into your own calendar
Get the full 12-month version for your exact ZIP — every sowing, transplant, and harvest window, with reminders you can add to your calendar. Free, no account needed to try.