Basil in Zone 3a & 3b
Ocimum basilicum
Yes, basil grows in zones 3a and 3b. Start seeds indoors Apr 18–Apr 25 and plant out Jun 13–Jun 20.
When to plant basil in zone 3b
Zones 3a and 3b share the same average frost dates, so this page covers both.
Method: Start indoors: Start indoors from seed, then transplant outside. It needs a head start most zones can't give it by direct-sowing alone.
| Start indoors | Apr 18–Apr 25 |
|---|---|
| Direct sow / transplant outside | Jun 13–Jun 20 |
| Estimated harvest | Aug 12–Aug 19 (~60 days after transplanting) |
Spacing: 4 per square foot (square-foot-gardening spacing). Mature height: 1-2 ft.
Plant alongside it in zone 3b
These go outside within two weeks of basil in zone 3b, so one planting day can cover them.
- BorageMay 30–Jun 6
- TobaccoJun 13–Jun 20
- CuminJun 20–Jun 27
- HyssopJun 6–Jun 13
- Lemon BalmJun 6–Jun 13
- Shiso (Perilla)Jun 6–Jun 13
Basil is arguably the best value crop in a home garden: a single plant produces far more than the tiny, expensive plastic clamshells at the grocery store, and fresh-cut basil's flavor fades within days of harvest, so growing your own is a genuine upgrade over what a grocery-store clamshell gets you, well beyond the money saved.
How basil fits zone 3's season
Zone 3b's frost-free window runs about 98 days, from May 30 to September 5. Basil needs about 60 days from transplant to first harvest.
Basil planting windows in every zone
Zone 3b 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 (your zone) | Apr 18–Apr 25 | Jun 13–Jun 20 | Aug 12–Aug 19 |
| 4a & 4b | Apr 3–Apr 10 | May 29–Jun 5 | Jul 28–Aug 4 |
| 5a & 5b | Mar 29–Apr 5 | May 24–May 31 | Jul 23–Jul 30 |
| 6a & 6b | Mar 14–Mar 21 | May 9–May 16 | Jul 8–Jul 15 |
| 7a & 7b | Feb 27–Mar 6 | Apr 24–May 1 | Jun 23–Jun 30 |
| 8a & 8b | Feb 11–Feb 18 | Apr 8–Apr 15 | Jun 7–Jun 14 |
| 9a & 9b | Jan 4–Jan 11 | Mar 1–Mar 8 | Apr 30–May 7 |
| 10a & 10bSpring window | Jan–Jul | Feb–Aug | ~60 days after transplanting |
| 11a & 11b | Nov 20–Nov 27 | Jan 15–Jan 22 | Mar 16–Mar 23 |
Harvest dates are about 60 days after the sow or plant-out date, not after starting seeds indoors.
Good companions
- Tomato: Reputed to improve tomato flavor and repel pests, but a multi-year, garden-scale controlled trial found no consistent taste preference in blind tests, and no pest-reduction benefit: treat this as one of companion planting's least-supported popular claims.
- Bell Pepper: Reputed to repel aphids and improve growth nearby, but the same controlled trial that tested basil's tomato pairing found no pest-reduction benefit on a related crop, and even higher pest counts in one case: treat this as unproven.
Where to buy basil seeds
Botanical Interests · True Leaf Market · Burpee · High Mowing Organic Seeds (each supplier's basil seeds)
Varieties we recommend, and where to get them:
- Rutgers Devotion DMR: One of the first Rutgers-bred downy mildew resistant releases. Buy: High Mowing Organic Seeds Full notes
- 'Genovese' (best for classic pesto flavor): Johnny's describes large, 3-inch dark green leaves with authentic Italian flavor on a tall, relatively slow-to-bolt plant, the standard culinary type all three disease-resistant varieties above are ultimately bred to match in flavor. Buy: Botanical Interests · True Leaf Market · Burpee · High Mowing Organic Seeds Full notes
- Sweet Thai (best for Asian cooking, ornamental stems): Johnny's lists purple stems and blooms against green leaves, with a spicy anise-clove flavor entirely different from Genovese's sweet Italian profile, at 64 days. Buy: Botanical Interests · High Mowing Organic Seeds Full notes
See why we recommend these suppliers →
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See it growing
Search YouTube for "growing basil" videos → (a live search, not a hand-picked video; results vary and aren't vetted by us)
← Back to the full zone 3b calendar · Plan your beds in the Garden Designer →
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Growing Basil in USDA zone 3b: when to start seeds indoors, when to direct-sow, and when to expect a harvest.
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