How to grow basil
Family Lamiaceae. Hardy to USDA hardiness zone 3a+ (U.S. Department of Agriculture). Full sun, 6-8 hrs. Ready in 60-90 days.
Sun
Full sun, 6-8 hrs
Spacing
10-12 in
Days to harvest
60-90 days
Hardiness
Zone 3a+
What growers actually recorded
Loading zone 7b results…
When to plant basil
- Start indoors: ~6 weeks before last frost.
- Transplant out: ~2 weeks after last frost.
- Direct sow: ~2 weeks after last frost.
Companion plants for basil
Plant with: Tomato, Pepper, Oregano.
Avoid near: Rue, Sage.
Common pests & problems
Japanese beetle, aphids. Pinch weekly to keep it bushy.
Feeding & fertilizer
N-P-K ratio: Low fertilizer: herbs go bland when overfed
Organic options: Compost once at planting · Weak fish emulsion once mid-season if pale · Nothing after that
When to feed: Feed lightly if at all. Mediterranean herbs (rosemary, thyme, oregano) thrive in lean soil.
Watch for: Fast, floppy, weak-flavored growth = too rich.
N = nitrogen (leaves), P = phosphorus (roots and flowers), K = potassium (fruit and disease resistance). How to read a fertilizer label →
Grower's tip
Pinch flower spikes the moment you see them: leaves stay sweet all season.
When to plant basil in your zone
Free month-by-month sowing and transplanting lists, built from frost dates for your USDA (United States Department of Agriculture) hardiness zone.
Soil & water for basil
Soil & pH
6.0-7.5
Well-drained, on the lean side. Mediterranean herbs rot in rich wet soil.
Compost once at planting, then leave the bed alone. Add grit or perlite for rosemary and thyme.
Watering
0.5-1 in / week: under-water rather than over-water
Deep, infrequent watering builds essential oils and flavor.
Pinch a leaf and smell it. If the aroma is weak and the growth is soft and floppy, the plant is over-watered or over-fed. If the leaf is stiff and fragrant, you're doing it right.
Knowing when to harvest
- Pinch top 4-6 in above a leaf pair once the plant has 6 nodes.
- Cut before flowers open. Flowering diverts sugars and dulls flavor.
- Morning harvest = highest oil content.
Storing & keeping
Stems in a jar of water on the counter. 1 week. Freeze whole leaves in oil, or dry (loses flavor).
What to expect
Per plant: 0.5-1 lb over the season with regular pinching
Troubleshooting basil
Blackened leaves overnight
Likely cause: Cold shock below 50°F
What to do: Cover during cool spells; wait until nights are steady 55°F+ to plant out.
Downy mildew (yellow tops, gray spore mass below)
Likely cause: Warm-wet weather
What to do: Choose resistant varieties (Prospera, Rutgers Devotion); improve airflow.
Varieties worth growing
Genovese
The classic for pesto and Italian cuisine.
Thai (holy or sweet)
Anise-clove flavor; heat-tolerant.
Prospera DMR
Downy-mildew-resistant. The answer for humid climates.
Growing basil in containers
1 gallon per plant; window boxes work great.
Nutrition
Volatile oils that hold up after drying: rosmarinic acid in rosemary, thymol in thyme, menthol in mint, eugenol in basil and oregano. That's why a pinch of dried herb often tastes stronger than a handful of fresh. The oils are concentrated once the water leaves.
Common questions
Why is my basil bitter?
Cold shock, over-water, or letting it flower. Pinch flower spikes immediately when they appear.
Where these numbers come from
- USDA Plant Hardiness Zone Map (2023 revision). Zone assignment and the 30-year normals behind every cold-hardiness figure.
- NOAA NCEI 1991-2020 Climate Normals. Frost dates, growing-season length, and the probability bands on both.
- Cornell, UMN, and UC Davis Cooperative Extension crop guides. Spacing, days to maturity, soil pH targets, and per-plant yield ranges.
- USDA FSIS / FDA Produce Safety guidance. Wash, cure, and cold-storage handling numbers.
Ranges are regional guidance, not a promise for your yard. Your own logged results always override the published range.