Mustard Greens in Zone 3a & 3b
Brassica juncea
Yes, mustard greens grow in zones 3a and 3b. Plant them outside May 9–May 16.
When to plant mustard greens in zone 3b
Zones 3a and 3b share the same average frost dates, so this page covers both.
Method: Direct sow: Direct-sow outside. It doesn't transplant well, or doesn't need the extra time indoors.
| Start indoors | Not typically started indoors |
|---|---|
| Direct sow / transplant outside | May 9–May 16 |
| Estimated harvest | Jun 18–Jun 25 (~40 days after direct-sowing) |
Spacing: 4 per square foot (square-foot-gardening spacing). Mature height: 1-2 ft.
Plant alongside it in zone 3b
These go outside within two weeks of mustard greens in zone 3b, so one planting day can cover them.
- OnionMay 9–May 16
- RadishMay 2–May 9
- CabbageMay 16–May 23
- BeetMay 9–May 16
- Broccoli Rabe (Raab)May 9–May 16
- MizunaMay 9–May 16
Mustard greens are one of the fastest crops you can grow for a full harvest, direct-sown and ready to cut in under six weeks, with a peppery bite that gets sharper the longer a leaf sits on the plant. They're also one of the most cold-tolerant greens, holding up to frost that would finish off lettuce.
How mustard greens fit zone 3's season
Zone 3b's frost-free window runs about 98 days, from May 30 to September 5. Mustard greens need about 40 days from sowing to first harvest.
Mustard Greens planting windows in every zone
Zone 3b is highlighted. Useful for comparing against a neighbouring zone, or for a garden somewhere else.
| Zone | Start indoors | Sow or plant out | Harvest |
|---|---|---|---|
| 2a & 2b | Not usually | Apr 29–May 6 | Jun 8–Jun 15 |
| 3a & 3b (your zone) | Not usually | May 9–May 16 | Jun 18–Jun 25 |
| 4a & 4b | Not usually | Apr 24–May 1 | Jun 3–Jun 10 |
| 5a & 5b | Not usually | Apr 19–Apr 26 | May 29–Jun 5 |
| 6a & 6b | Not usually | Apr 4–Apr 11 | May 14–May 21 |
| 7a & 7b | Not usually | Mar 20–Mar 27 | Apr 29–May 6 |
| 8a & 8b | Not usually | Mar 4–Mar 11 | Apr 13–Apr 20 |
| 9a & 9b | Not usually | Jan 25–Feb 1 | Mar 6–Mar 13 |
| 10a & 10b | Not usually | Jan 9–Jan 16 | Feb 18–Feb 25 |
| 11a & 11bFall window | Not usually | Sep–Jan | ~40 days after direct-sowing |
Harvest dates are about 40 days after the sow or plant-out date.
Zone 2 sows before zone 3 here, which looks wrong and is not. USDA zones rank winter cold, not season length, and zone 2 is mostly interior Alaska, where hard winters come with warm summers. More on what a zone measures.
Good companions
- Lettuce: Similar light/water needs for a shared salad bed.
- Carrot: Non-competing pairing with mutual pest benefit.
Where to buy mustard greens seeds
High Mowing Organic Seeds (each supplier's mustard greens seeds)
Varieties we recommend, and where to get them:
- Southern Giant Curled: Listed by University of Florida IFAS Gardening Solutions as one of the mustard cultivars recommended for Florida gardens, alongside Florida Broad Leaf, Tendergreen, Giant Red, Green Wave, and Mizuna. Buy: True Leaf Market · Burpee Full notes
- Ruby Streaks: Fine, deeply lobed dark green and maroon leaves, ready in 21 days as baby leaf or 40 for full size, per Johnny's. Buy: High Mowing Organic Seeds Full notes
- Red Giant: A broadleaf type with purple-tinted, gently scalloped leaves, very slow to bolt per Johnny's, which matters more than flavor once summer heat arrives and the fast-bolting types are already finished. Buy: Botanical Interests · True Leaf Market · Burpee · High Mowing Organic Seeds Full notes
See why we recommend these suppliers →
As an Amazon Associate we earn from qualifying purchases. Some links on this page also go to other retailers we may earn a commission from as an affiliate, at no extra cost to you. We only recommend products with a clear consensus of positive, independent reviews, or ones we bought and use ourselves. Each item on our gear page says which.
See it growing
Search YouTube for "growing mustard greens" videos → (a live search, not a hand-picked video; results vary and aren't vetted by us)
← Back to the full zone 3b calendar · Plan your beds in the Garden Designer →
Pin this for later
Growing Mustard Greens in USDA zone 3b: when to start seeds indoors, when to direct-sow, and when to expect a harvest.
Save to Pinterest