Horehound in Zone 4a & 4b

Marrubium vulgare

When to plant horehound in zone 4b

Zones 4a and 4b 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 1–May 8
Estimated harvest	Apr 30 '28–May 7 '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 4's season

Zone 4b's frost-free window runs about 128 days, from May 15 to September 20. 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 4b 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

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