Watercress in Zone 4a & 4b
Nasturtium officinale
Yes, watercress grows in zones 4a and 4b. Start seeds indoors Apr 24–May 1 and plant out May 1–May 8.
When to plant watercress in zone 4b
Zones 4a and 4b share the same average frost dates, so this page covers both.
Method: Either: Start indoors for an earlier harvest, or direct-sow outside for less fuss. Either works.
| Start indoors | Apr 24–May 1 |
|---|---|
| Direct sow / transplant outside | May 1–May 8 |
| Estimated harvest | Jun 20–Jun 27 (~50 days after planting) |
Spacing: 9 per square foot (square-foot-gardening spacing). Mature height: 4-10 in.
Plant alongside it in zone 4b
These go outside within two weeks of watercress in zone 4b, so one planting day can cover them.
- OnionApr 24–May 1
- RadishApr 17–Apr 24
- CarrotApr 24–May 1
- CabbageMay 1–May 8
- LettuceMay 1–May 8
- BroccoliMay 1–May 8
Watercress is the plant upland cress is compared against and named for, a peppery salad green that shares its flavor but is harder to grow, since it needs constantly saturated soil rather than an ordinary garden bed.
How watercress fits zone 4's season
Zone 4b's frost-free window runs about 128 days, from May 15 to September 20. Watercress needs about 50 days from sowing to first harvest.
Watercress planting windows in every zone
Zone 4b is highlighted. Useful for comparing against a neighbouring zone, or for a garden somewhere else.
| Zone | Start indoors | Sow or plant out | Harvest |
|---|---|---|---|
| 3a & 3b | May 9–May 16 | May 16–May 23 | Jul 5–Jul 12 |
| 4a & 4b (your zone) | Apr 24–May 1 | May 1–May 8 | Jun 20–Jun 27 |
| 5a & 5b | Apr 19–Apr 26 | Apr 26–May 3 | Jun 15–Jun 22 |
| 6a & 6b | Apr 4–Apr 11 | Apr 11–Apr 18 | May 31–Jun 7 |
| 7a & 7b | Mar 20–Mar 27 | Mar 27–Apr 3 | May 16–May 23 |
| 8a & 8b | Mar 4–Mar 11 | Mar 11–Mar 18 | Apr 30–May 7 |
| 9a & 9b | Jan 25–Feb 1 | Feb 1–Feb 8 | Mar 23–Mar 30 |
| 10a & 10b | Jan 9–Jan 16 | Jan 16–Jan 23 | Mar 7–Mar 14 |
Harvest dates are about 50 days after the sow or plant-out date, not after starting seeds indoors.
Good companions
No well-established companions for watercress.
Where to buy watercress seeds
Botanical Interests (each supplier's watercress seeds)
See why we recommend these suppliers →
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See it growing
Search YouTube for "growing watercress" videos → (a live search, not a hand-picked video; results vary and aren't vetted by us)
← Back to the full zone 4b calendar · Plan your beds in the Garden Designer →
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Growing Watercress in USDA zone 4b: when to start seeds indoors, when to direct-sow, and when to expect a harvest.
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