Horehound in Zone 3a & 3b
Marrubium vulgare
When to plant horehound in zone 3b
Zones 3a and 3b share the same average frost dates in our data, so this page covers both.
Method: Direct sow: Direct-sow outside. Horehound doesn't transplant well, or doesn't need the extra time indoors.
| Start indoors | Not typically started indoors |
|---|---|
| Direct sow / transplant outside | May 16–May 23 |
| Estimated harvest | May 15 '28–May 22 '28 (First real harvest the season after planting) |
Spacing: 1 per square foot (square-foot-gardening spacing). Mature height: 1-2 ft.
Horehound is a grey-green, woolly-leaved mint relative grown for a bitterness that mostly appears in throat lozenges.
How horehound fits zone 3's season
Zone 3b's frost-free window runs about 98 days, from May 30 to September 5. Horehound takes about 1 growing season to reach first worthwhile harvest, so what matters here is how many of these seasons it gets, not whether one is long enough.
Horehound is hardy in zones 3-9, so in zone 3b it stays in the ground through winter and comes back rather than being replanted. Allow about 1.5 ft of spread at maturity.
Good companions
No standout companions recorded yet for Horehound.
Where to buy horehound seeds
See why we recommend these suppliers →
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See it growing
Search YouTube for "growing horehound" videos → (a live search, not a hand-picked video; results vary and aren't vetted by us)
← Back to the full zone 3b calendar · Full companion planting guide · Full plant profile · Plan your beds in the Garden Designer →

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Growing Horehound in USDA zone 3b: when to start seeds indoors, when to direct-sow, and when to expect a harvest.
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