Herb · Lamiaceae
Basil
Ocimum basilicum
Give it warmth, sun, and a regular pinch, and basil keeps the kitchen in fresh leaves all summer.
Full sun
Every 7–10 days
50–86°F · 10–30°C
60–90 days
Overview
Basil is the herb most cooks reach for first, a tender annual in the mint family that traces back to the warm parts of Asia and Africa. It grows fast and loves heat, which makes it just as easy in a backyard bed as in a pot on a sunny sill. Give it warmth and light and it rewards you with armfuls of fragrant leaves.
The plant lives for a single season and runs from 12 to 24 inches (30 to 60 cm) tall depending on the type. Left alone it climbs, flowers, and sets seed, but a gardener who keeps pinching the tips steers all that energy back into leaves. That one habit, more than anything, decides how much you get to harvest.
Basil forgives a beginner but has two firm rules. It will not stand frost or cold soil, and it sulks fast in damp, crowded air where downy mildew takes hold. Keep it warm, give it room to breathe, and water at the base, and the rest comes easily.
Care
The short version: full sun and warmth, with soil kept evenly moist and watered at the base to keep the leaves dry. Feed lightly, pinch the tips often, and never rush it into cold ground.
Light
Basil wants full sun, ideally six or more hours a day, which is what builds the oils behind its flavor. It will take some afternoon shade where summers run brutal, but too little light leaves you with leggy, weak plants.
Water
Keep the soil evenly moist, watering thoroughly every 7 to 10 days depending on rain. Plants in pots dry out faster and need checking more often. Always water at the base, since wet leaves are an open door to downy mildew.
Soil
Plant in rich, well drained loam worked over with compost. A pH between 6.0 and 7.5 suits basil well, so most decent garden soil works without much fuss.
Temperature
Basil thrives in warmth, roughly 50°F to 86°F (10°C to 30°C), and grows fastest at the top of that range. It will not tolerate frost, and cold soil stunts young plants, so warmth comes first.
Humidity
Average humidity of 40% to 60% is plenty, so there's no number to chase. What matters far more is airflow, since still, damp air around crowded plants is how downy mildew gets started.
Feeding
Go light here. A balanced fertilizer such as 5-10-5 once or twice across the season is all basil needs, and feeding sparingly keeps the flavor strong, since too much growth thins out the oils.
Pruning
Pinch the growing tips often to push the plant into bushy side branches, and snap off any flower buds the moment they appear. That steady pinching is what keeps the leaves coming and the flavor full.
Repotting
Grown as an annual, basil rarely needs true repotting. Just pot up seedlings into roomier containers as they outgrow the last one, before the roots start circling and the soil dries out too fast.
Size & spacing
Plants reach 12 to 24 inches (30 to 60 cm) tall and spread 12 to 18 inches (30 to 45 cm) wide. Give each one that much room so air can move freely and disease stays down.
When to plant
Basil is all about warmth and has zero tolerance for frost. Start seeds indoors in late winter, set plants out only once the cold has fully passed and the soil is warm, then harvest leaves right through summer until the first frost ends the season.
Northern hemisphere
Southern hemisphere
Typical months for a temperate climate: start earlier in warm zones, later where spring frosts linger.
- Sow: 6-8 weeks before the last spring frost; germinates best at media temperatures of at least 70°F
- Plant: After all danger of frost when soil is warm and nighttime temperatures stay above 50°F
- Harvest: Harvest leaves continually once plants have several sets of leaves; pinch off flower buds to delay bolting and prolong leaf production
Hardiness
USDA hardiness zones: 2–11
Temperature: down to -46°C
Troubleshooting
Most basil trouble shows up on the leaves first, whether it's disease, a hungry pest, or the plant trying to flower. Learn the early signs and you can step in before a small problem spreads. Match what you see below, then act while it still helps.
Yellow blotches up top with gray-purple fuzz underneath
This is basil downy mildew, a fast-moving disease that loves damp leaves and still air. Pull and destroy affected plants the moment you spot it, since there's no saving them once the fuzz appears. Give the rest more room, water at the base, and lean on resistant types like 'Prospera' next time.
Fix:
- Remove and destroy affected plants immediately
- Increase plant spacing and prune for airflow
- Water at the base to keep foliage dry
Sudden wilt with brown streaks running up the stem
Fusarium wilt is a soil fungus that plugs the stem from the inside, and there's no cure once it takes hold. Pull the plant, bin it rather than compost it, and start over somewhere else with fresh, clean media. Resistant cultivars and disease-free seed are the surest way to keep it out.
Fix:
- Remove and destroy infected plants
- Do not compost affected material
- Replant in a different location or use fresh sterile media
Mushy dark roots and a plant sulking in cold, wet soil
Root rot sets in when soil stays waterlogged or too cold for the roots to cope. Healthy roots are firm and white, but rotted ones turn soft, brown, and foul-smelling. Improve the drainage, ease off the watering, and wait until the soil is warm, above 50°F (10°C), before you set plants out.
Fix:
- Improve drainage and reduce watering frequency
- Remove severely affected plants
- Allow soil to dry between waterings
Flower spikes at the tips and leaves that lose their punch
This is bolting, the plant's push to set seed once it matures or the days turn long and hot. Once flower spikes form, new leaves come in smaller and taste flatter. Pinch off the buds as soon as you see them and keep harvesting, and the plant stays leafy and full of flavor.
Fix:
- Pinch off flower buds as soon as they appear
- Harvest and prune leaves regularly to delay flowering
Ragged holes chewed through the leaves
Two culprits do this. Japanese beetles strip leaves down to a lace of veins by day, while slugs and snails chew holes overnight and leave shiny trails behind. Pick the beetles into soapy water, set traps or barriers for the slugs, and catch them early before the numbers climb.
Fix:
- Hand-pick beetles into soapy water
- Apply insecticidal soap for soft-bodied pests
- Set out slug traps or barriers
Toxicity
Good news on this one. Basil is non-toxic and grown to be eaten, so it's safe around cats, dogs, horses, rabbits, livestock, birds, and children alike. The worst a curious pet might get from a big mouthful is a brief, mild stomach upset that passes on its own.
Safe for
People · Cats · Dogs · Horses · Rabbits · Livestock · Birds
Cats None
Basil is safe for cats, and a nibble does no harm. A cat that gorges on any plant might bring it back up, but that passes on its own.
Dogs None
Dogs can eat basil without trouble. The worst a big mouthful might do is a brief, mild upset stomach that clears quickly.
Horses Safe
Horses are fine around basil. There's nothing in the plant that harms them.
Rabbits Safe
Rabbits can graze on basil freely, and many take to the fresh leaves as a welcome treat.
Livestock Safe
Goats, sheep, and cattle can browse basil with no ill effect.
Birds Safe
Basil poses no risk to birds, and backyard hens will happily peck at the leaves.
People Safe
Basil is a kitchen herb grown to be eaten, raw or cooked, with nothing to worry about for adults or children.
No special handling precautions are needed; basil is non-toxic and edible.
Varieties
Dozens of basils exist, from sweet Italian types to spicy and ornamental kinds, but a handful turn up in most gardens. These are the ones worth knowing by name.
Genovese
The classic large-leaved Italian sweet basil and the first choice for pesto, though its rich flavor comes paired with the worst susceptibility to downy mildew.
Thai basil
An anise and licorice flavored type with purple stems that reaches 24 to 36 inches and anchors much of Southeast Asian cooking.
Purple Ruffles
An ornamental grown as much for its deep purple, ruffled leaves as for the kitchen.
Spicy Globe
A tidy mounding basil only 8 to 10 inches tall that fits neatly into pots and edging.
Prospera
A Genovese-style basil bred to shrug off downy mildew, with a compact form suited to container growing.
Companions
Basil earns its old reputation as a tomato's best neighbor, sharing the same warm, sunny, well-drained ground the two crops both want.
Plant near
Tomato: Basil is a traditional interplanting companion for tomatoes in the vegetable garden, sharing similar warm-season, full-sun, well-drained growing conditions.
How to propagate
Basil is one of the easiest plants to multiply, whether you start from a seed packet or take free copies of a plant you already grow.
SeedEasy
Sow indoors 6-8 weeks before last frost or direct sow after frost when soil is warm · Germinates in 5-10 days at about 70°F; transplant-ready in roughly 3-4 weeks
Most gardeners start basil from seed. Sow it about a quarter inch deep, 6 to 8 weeks before your last frost, and keep the media warm at 70°F (21°C) or more for reliable sprouting. Seedlings break ground in 5 to 10 days and are ready to transplant in about 3 to 4 weeks, or you can direct sow once the soil warms.
Stem cuttingsEasy
Any time during the growing season from healthy non-flowering shoots · Roots form in water in about 1-2 weeks
Basil clones itself with no fuss at all. Take a 4-inch cutting from a healthy, non-flowering shoot any time in the growing season, strip the lower leaves, and stand it in water, where roots form in a week or two before you pot it up into a copy of the parent plant.
Myths
Once basil flowers, the leaves turn toxic and have to be thrown out.
Flowering basil stays perfectly safe to eat. The leaves just lose some of their punch as the plant puts its energy into seed, which is why gardeners pinch off the buds, not because anything has gone bad.
Basil needs constant heavy feeding to grow well.
It does better on a light hand. Too much fertilizer thins out the oils that give the leaves their flavor, so a feed once or twice a season is plenty.