Thyme in Zone 5a & 5b
Thymus vulgaris
When to plant thyme in zone 5b
Zones 5a and 5b share the same average frost dates in our data, so this page covers both.
Method: Start indoors: Start indoors from seed, then transplant outside. Thyme needs a head start most zones can't give it by direct-sowing alone.
| Start indoors | Mar 15–Mar 22 |
|---|---|
| Direct sow / transplant outside | May 17–May 24 |
| Estimated harvest | Aug 15–Aug 22 (~90 days after transplanting) |
Spacing: 4 per square foot (square-foot-gardening spacing). Mature height: 0.5-1 ft.
Thyme is a low, spreading perennial, not an annual herb you replant each spring. Once established, it comes back reliably year after year and slowly fills in as a groundcover.
How thyme fits zone 5's season
Zone 5b's frost-free window runs about 148 days, from May 10 to October 5. Thyme needs about 90 days from transplant to first harvest.
Good companions
- Cabbage: Penn State Extension lists thyme among the herbs that measurably deter cabbage loopers on brassicas, the same protective role sage and dill play.
Where to buy thyme seeds
See why we recommend these suppliers →
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See it growing
Search YouTube for "growing thyme" videos → (a live search, not a hand-picked video; results vary and aren't vetted by us)
← Back to the full zone 5b calendar · Full companion planting guide · Full plant profile · Plan your beds in the Garden Designer →
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Growing Thyme in USDA zone 5b: when to start seeds indoors, when to direct-sow, and when to expect a harvest.
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