What to Plant in March in Zone 3
Here is what you can sow in March if you garden in USDA zone 3. Dates use typical zone 3 frosts, so your own microclimate may shift them by a week or two.
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| Crop | Window | Sow between |
|---|---|---|
| Snap PeaSugar Snap | spring | Mar 24 – May 5 |
| SpinachBloomsdale | spring | Mar 24 – May 5 |
| CabbageTiara | spring | Mar 24 – Apr 21 |
| BroccoliBelstar | spring | Mar 24 – Apr 21 |
| CauliflowerSnow Crown | spring | Mar 24 – Apr 20 |
| Onion, bulbTexas Legend | spring | Mar 7 – Apr 20 |
| English Shelling PeaLittle Marvel | spring | Mar 24 – May 5 |
| Napa CabbageBlues F1 | spring | Mar 31 – Apr 25 |
| Rapini (Broccoli Raab)Zamboni F1 | spring | Mar 26 – Apr 25 |
| Gai Lan (Chinese Broccoli)Crispy Blue | spring | Mar 28 – Apr 27 |
| TatsoiTatsoi | spring | Mar 21 – Apr 25 |
| MizunaMizuna Early | spring | Mar 21 – May 1 |
| Daikon RadishMiyashige | spring | Mar 31 – Apr 25 |
| SorrelProfusion | spring | Mar 24 – May 5 |
| ParsnipHollow Crown | spring | Feb 20 – Apr 3 |
| LeekLincoln | spring | Feb 20 – Apr 3 |
| ShallotAmbition | spring | Mar 20 – Apr 24 |
| SalsifyMammoth Sandwich Island | spring | Mar 20 – Apr 24 |
| CeleriacPrinz | spring | Feb 6 – Mar 20 |
| Onion | spring | Mar 7 – Apr 20 |
| Mache (Corn Salad)Vit | spring | Mar 31 – May 8 |
Zone 3 in March
March in Zone 3: The Cold-Hardy Half of the List Opens
The soil thermometer, not the calendar, still runs this month
Snap peas, spinach, and the fast brassica greens on this month's list wait for soil to hold 40 degrees at a 2 inch depth, measured with an actual soil thermometer rather than guessed from air temperature. Push the probe in mid-morning, not right after a cold night, for a reading that reflects the day. With a mid-May last frost here, that 40 degree reading commonly does not show up at 2 inches until April, so treat a cold March reading as expected rather than a sign anything is behind.
Cabbage, broccoli, and cauliflower stay indoors this month rather than moving into open ground. Start seed trays under lights now, so the plants reach a sturdy size by the time soil actually warms enough to receive them, since a transplant set into ground still near freezing at root depth just sits and sulks under any cover you put over it.
This is the last call for celeriac starts
If you have not started celeriac seed indoors yet, this month closes that window for good this season. Celeriac needs 10 to 12 weeks from sowing to a transplant-ready size, so a start right now still lands close to when the ground opens up for transplanting in May.
Soak the tiny seed overnight before sowing to speed up an otherwise sluggish start. Even with a soak, expect the first sprout to take 2 to 3 weeks to show, so do not assume a bare tray means a failed packet until well past that point.
Row cover earns its keep this early
A floating row cover rated for 4 to 6 degrees of frost protection turns a risky March sowing into a safe one. Lay it loose over newly seeded rows of spinach or peas, weight the edges with soil or rocks, and expect germination to run about 3 to 5 days faster underneath it than in open ground.
March in zone 3: common questions
What can I plant in March in zone 3?+
In March, USDA zone 3 gardeners can sow Snap Pea, Spinach, Cabbage, Broccoli, Cauliflower, Onion, bulb, and more. Dates use typical zone 3 frosts, so your own microclimate may shift them by a week or two.
What USDA hardiness zone am I in?+
Zone 3 is one band of the map, but planting time is set by your local frost dates, not the zone number. Enter your ZIP code in the free planner and it uses your actual frost dates, which can differ by weeks within a single zone.
Are these March planting dates exact?+
They are typical zone 3 windows. Two gardens in the same zone can be a week or two apart because of elevation and local climate, so treat these as a starting point and tune them to your ZIP code with the free planner.