Oca in Zone 6a & 6b
Oxalis tuberosa
Yes, oca grows in zones 6a and 6b. Plant it outside Apr 25–May 2.
When to plant oca in zone 6b
Zones 6a and 6b 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 | Apr 25–May 2 |
| Estimated harvest | Nov 21–Nov 28 (~210 days after direct-sowing) |
Spacing: 1 per square foot (square-foot-gardening spacing). Mature height: 0.5-1.5 ft.
Plant alongside it in zone 6b
These go outside within two weeks of oca in zone 6b, so one planting day can cover them.
- CabbageApr 11–Apr 18
- TomatoMay 9–May 16
- Bush BeansMay 2–May 9
- Sweet CornMay 2–May 9
- LettuceApr 11–Apr 18
- CucumberMay 2–May 9
Oca is an Andean tuber crop, a relative of potato with vividly colored roots in reds, yellows, and oranges, and a genuine growing quirk that sets it apart from anything else here.
How oca fits zone 6's season
Zone 6b's frost-free window runs about 173 days, from April 25 to October 15. Oca needs about 210 days from sowing to first harvest.
Oca planting windows in every zone
Zone 6b is highlighted. Useful for comparing against a neighbouring zone, or for a garden somewhere else.
| Zone | Start indoors | Sow or plant out | Harvest |
|---|---|---|---|
| 6a & 6b (your zone) | Not usually | Apr 25–May 2 | Nov 21–Nov 28 |
| 7a & 7b | Not usually | Apr 10–Apr 17 | Nov 6–Nov 13 |
| 8a & 8b | Not usually | Mar 25–Apr 1 | Oct 21–Oct 28 |
| 9a & 9b | Not usually | Feb 15–Feb 22 | Sep 13–Sep 20 |
Harvest dates are about 210 days after the sow or plant-out date.
Good companions
No well-established companions for oca.
Where to buy oca seeds
None of the seed suppliers we list carries oca seeds right now. A local garden center or a specialty seed house is the place to look.
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 oca" videos → (a live search, not a hand-picked video; results vary and aren't vetted by us)
← Back to the full zone 6b calendar · Plan your beds in the Garden Designer →
Pin this for later
Growing Oca in USDA zone 6b: when to start seeds indoors, when to direct-sow, and when to expect a harvest.
Save to Pinterest