DibbleWhen to plant Swiss chard in Zone 4
In Zone 4, the last spring frost usually passes around May 10 and the first fall frost arrives around September 21, leaving about 134 frost-free days. The windows below are computed from those frost dates, with the same math the Dibble app uses.
Cool climate with a brief warm window. Indoor starts and season extension help.
Planting windows for Swiss chard in Zone 4
| Task | Window |
|---|---|
| Direct sow | Apr 26 to May 10 |
| Estimated harvest | Jun 20 to Oct 18 |
The harvest estimate counts 55 days to maturity, then a picking window of about 120 days. These windows use typical frost dates for Zone 4; Dibble pins them to your exact ZIP code.
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Swiss Chard in a Zone 4 season
Zone 4 gives about 134 frost-free days. Swiss Chard needs roughly 55 days from sowing. That leaves about 79 days of slack, so there is room for a late start or a second planting.
How to grow Swiss chard
Sow chard once the soil is workable and no longer cold. Pick the outer leaves and it keeps producing for many months. It shrugs off heat better than spinach or lettuce.
Companion plants
Good neighbors for Swiss Chard:
Swiss Chard in other zones
Not in Zone 4? Pick your zone for the same dated windows.
Keep exploring
Swiss Chard: the full growing guide · The Zone 4 planting calendar · Every crop and zone
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Dates are estimates based on typical frost dates for the zone. Your yard has its own microclimate, so use them as a starting point and adjust as you learn your space.