Herb · Lamiaceae
Basil
Ocimum basilicum
Hand it sun, warmth, and a steady pinch, and you'll have fresh basil for the kitchen all summer long.
Full sun
Every 7–10 days
50–86°F · 10–30°C
60–90 days
Overview
Basil tends to be the first herb a cook grabs, a tender annual from the mint family with roots back in the hot stretches of Asia and Africa. It puts on growth in a hurry and adores heat, so it settles in just as happily in a garden bed as in a pot perched on a bright windowsill. Treat it to warmth and plenty of light and you'll be cutting handfuls of fragrant leaves.
One season is all this plant gets, and it stands somewhere between 12 to 24 inches (30 to 60 cm) tall depending on which kind you grow. Leave it be and it'll shoot up, bloom, and go to seed, but keep pinching those tips and you redirect all of that effort straight back into foliage. No single habit shapes your harvest more than that one.
Basil is gentle on beginners, yet it draws two hard lines. Frost and cold ground are out of the question, and it goes downhill quick in muggy, packed-together air, the exact setting where downy mildew takes hold. Keep it toasty, leave space for air to move, and aim the water at the soil, and everything else falls into place.
Care
The short version: sun and warmth, soil that stays evenly moist, and water aimed at the base so the leaves stay dry. Keep the feeding light, pinch those tips regularly, and don't push it out into cold ground.
Light
Basil is after full sun, six hours a day or better, because that's what builds up the oils carrying its flavor. Where summers turn fierce it'll put up with a little afternoon shade, but starve it of light and you're left with floppy, feeble plants.
Water
Aim to keep the soil evenly moist, giving it a good soak every 7 to 10 days, more or less depending on the rain. Potted basil dries quicker, so look in on it more often. And always pour it on at the base, since wet leaves roll out the welcome mat for downy mildew.
Soil
Set it in rich, well drained loam that you've mixed some compost through. A pH anywhere from 6.0 and 7.5 keeps basil content, which means most halfway-decent garden soil does the job without much fuss.
Temperature
Warmth is basil's happy place, somewhere around 50°F to 86°F (10°C to 30°C), and it really takes off near the upper end. Frost is a no-go and cold ground stalls young plants, so warmth has to come first.
Humidity
An everyday humidity of 40% to 60% does the trick, so there's no figure to fuss over. Far more important is airflow, because still, soggy air pressed in around crowded plants is exactly how downy mildew gets its start.
Feeding
Keep a light hand here. One or two doses of a balanced fertilizer like 5-10-5 over the whole season is all basil asks for, and going easy keeps the flavor punchy, since too much push thins those oils out.
Pruning
Pinch the growing tips regularly to coax the plant into bushy side shoots, and snip off any flower buds the instant you spot them. It's that constant pinching that keeps the leaves coming and the taste at full strength.
Repotting
Since it's grown as an annual, basil hardly ever needs real repotting. Just move seedlings up into bigger pots as they outgrow the old one, doing it before the roots wind around and the soil starts drying too fast.
Size & spacing
Expect plants to hit 12 to 24 inches (30 to 60 cm) tall and fill out 12 to 18 inches (30 to 45 cm) across. Hand each one that much elbow room so the air keeps moving and disease has a harder time.
When to plant
With basil, warmth is the whole game, and frost is the dealbreaker. Get seeds started inside toward the end of winter, wait to move plants outdoors until the chill is truly gone and the ground has warmed, and then keep picking leaves clean through summer right up until that first frost calls it a day.
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
When basil runs into trouble, the leaves usually flag it first, be it a disease, a pest looking for lunch, or the plant getting ready to flower. Get to know those early tells and you can jump in before a little issue turns into a big one. Find the match below, then move while there's still time to help.
Yellow patches on top, gray-purple fuzz hiding beneath
What you're seeing is basil downy mildew, and it spreads quick wherever the leaves stay wet and the air sits still. Once that fuzz turns up there's no bringing a plant back, so yank the sick ones out and get rid of them right away. After that, spread the survivors apart, water down at the soil, and reach for a tough variety like 'Prospera' when you replant.
Fix:
- Remove and destroy affected plants immediately
- Increase plant spacing and prune for airflow
- Water at the base to keep foliage dry
A fast collapse with brown stripes climbing the stem
Blame Fusarium wilt here, a fungus living in the soil that clogs the stem from within, and once it's settled in there's nothing that fixes it. Lift the plant, toss it in the trash instead of the compost, and begin fresh in a new spot with clean media. Want to keep it from coming back? Lean on resistant varieties and seed you know is disease-free.
Fix:
- Remove and destroy infected plants
- Do not compost affected material
- Replant in a different location or use fresh sterile media
Soft dark roots and a plant moping in chilly, soggy ground
Root rot moves in once the ground stays soaked or runs too cold for the roots to handle. A healthy root feels firm and looks white, but a rotting one goes soft and brown and gives off a bad smell. Sort out the drainage, back off the watering can, and hold off planting outside until the ground warms past 50°F (10°C).
Fix:
- Improve drainage and reduce watering frequency
- Remove severely affected plants
- Allow soil to dry between waterings
Buds at the tips and leaves that taste like less
That's bolting, which is just the plant racing to make seed once it's grown up or the days stretch long and hot. As soon as those spikes show, the leaves arriving after them come in smaller and weaker on flavor. So nip the buds the second they appear and keep picking, and you'll hold onto a bushy plant with leaves that still taste like something.
Fix:
- Pinch off flower buds as soon as they appear
- Harvest and prune leaves regularly to delay flowering
Ragged bite marks punched right through the foliage
There are two suspects when holes appear. By daylight, Japanese beetles munch the green away until only a webbing of veins is left, while after dark slugs and snails do their gnawing and give themselves away with a glistening trail. Drop the beetles into a cup of soapy water, ring the plants with traps or barriers for the slimy ones, and stay on top of it before their numbers really take off.
Fix:
- Hand-pick beetles into soapy water
- Apply insecticidal soap for soft-bodied pests
- Set out slug traps or barriers
Toxicity
Here's the easy part. Basil is non-toxic and grown for eating, which makes it safe to have around cats, dogs, horses, rabbits, livestock, birds, and kids too. About the worst a nosy pet gets from a hearty mouthful is a short, mild bellyache that clears up by itself.
Safe for
People · Cats · Dogs · Horses · Rabbits · Livestock · Birds
Cats None
A curious cat can chew basil with zero risk. Gobble down too much of any greenery and it might come back up, but that sorts itself out fast.
Dogs None
Your dog is welcome to basil, no problem there. About the only downside to a greedy mouthful is a quick bout of mild tummy trouble that soon settles.
Horses Safe
Basil sits just fine with horses. Nothing in it is going to do them any harm.
Rabbits Safe
Let a rabbit nibble all the basil it likes; plenty of them treat the fresh leaves as a real favorite.
Livestock Safe
Goats, sheep, and cattle can all munch on basil and walk away none the worse.
Birds Safe
There's no danger to birds in basil, and your backyard chickens will gladly pick at the leaves.
People Safe
This is a cooking herb meant for the plate, eaten fresh or cooked, and it's perfectly fine for grown-ups and kids.
No special handling precautions are needed; basil is non-toxic and edible.
Varieties
There are dozens of basils out there, sweet Italian ones, spicy ones, ornamental ones, but only a few keep showing up in everyday gardens. These are the names worth getting to know.
Genovese
Think big-leaved Italian sweet basil and the go-to for pesto, though all that lovely flavor comes with the catch of being the most likely to catch downy mildew.
Thai basil
A purple-stemmed kind that tastes of anise and licorice, stretches to 24 to 36 inches, and shows up everywhere across Southeast Asian kitchens.
Purple Ruffles
More of a looker than a cook's herb, prized for its deep purple, frilly leaves.
Spicy Globe
A neat little mound of basil that tops out at just 8 to 10 inches, perfect for tucking into pots or lining a path.
Prospera
Bred in the Genovese mold but tough against downy mildew, and its compact shape makes it a natural for containers.
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 ranks among the simplest plants to make more of, whether you're tearing open a fresh seed packet or taking free copies off one you've already got.
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
Seed is how most folks get basil going. Tuck it roughly a quarter inch down, 6 to 8 weeks ahead of your last frost, and hold the media at 70°F (21°C) or warmer so it sprouts dependably. You'll see seedlings push up in 5 to 10 days, ready for transplant in about 3 to 4 weeks, or just sow straight into the bed once the ground has warmed.
Stem cuttingsEasy
Any time during the growing season from healthy non-flowering shoots · Roots form in water in about 1-2 weeks
Cloning basil couldn't be simpler. Snip a 4-inch piece off a healthy shoot that isn't flowering, do it any time through the season, pull the bottom leaves off, and pop it in a glass of water; roots show up in a week or two, and then it goes into a pot as a twin of the plant it came from.
Myths
Basil turns poisonous once it flowers and you have to bin it.
Flowering basil is still totally fine to eat. The leaves just go a bit milder as the plant pours its effort into making seed, which is the real reason gardeners pinch off the buds, not because anything's spoiled.
Basil has to be fed heavily and often to do well.
Honestly, it prefers a lighter touch. Pile on the fertilizer and you water down the oils that carry the flavor, so feeding it just once or twice a season covers it.