Basil Ocimum basilicum

Reviewed June 2026 · how we check this

The cornerstone culinary herb — a fast-growing, frost-tender annual with fragrant, tender leaves that perfume pesto, salads, and summer cooking. Loves heat and sun, sulks at the first chill, and rewards regular harvesting with bushy, continuous growth all season.

Light

Basil is a sun worshipper — give it at least 6 hours of direct sun a day, and more is better for compact, aromatic growth. In too little light it stretches, turns pale, and loses much of its essential-oil punch. Outdoors, choose the brightest spot you have; in containers, a south-facing patio or sunny windowsill works well. Indoors, a bright window often isn't enough, especially in winter, so supplement with a grow light positioned a few inches above the plants for 12–14 hours a day. In scorching, intense-sun climates a touch of afternoon shade during heat waves keeps leaves from scorching, but in most gardens, full sun is exactly what basil wants.

Watering

Keep the soil evenly moist but never waterlogged — basil likes a steady drink and wilts dramatically when it dries out, though it usually bounces back after watering. Water deeply at the base in the morning so the soil stays damp through the heat of the day, and avoid wetting the foliage to discourage fungal disease. In containers, which dry quickly, you may need to water daily in summer heat. Mulching outdoor plants conserves moisture and steadies the soil. Soggy, poorly drained soil leads to root rot and fusarium wilt, so always pair consistent moisture with good drainage.

Soil & potting

Plant basil in rich, well-drained soil amended with compost, at a slightly acidic to neutral pH of 6.0–7.0. It's a moderately heavy feeder that rewards fertile soil with lush, leafy growth. In containers, use a quality potting mix and a pot with drainage holes — at least 8 inches deep gives roots room to develop. Good drainage is essential; basil hates wet feet. If growing indoors year-round, refresh or pot up into fresh mix periodically, since basil exhausts container soil over a long season of fast growth.

Humidity & temperature

Basil is thoroughly warm-natured and frost-tender — it thrives at 70–90°F and stalls or yellows below 50°F, with even a light frost killing it outright. Wait until nights are reliably above 50°F before moving plants outdoors. Warm, gently humid conditions suit it, but stagnant, overly damp air invites downy mildew, so give plants spacing and airflow. In all but Zones 10–11 it's grown as an annual; elsewhere, bring a pot indoors before frost to extend the harvest, keeping it warm and brightly lit through winter. Protect early plantings from unexpected cold snaps with a cover.

Fertilizing

Basil grown for abundant leaves benefits from light, regular feeding. Work compost into the bed at planting, then feed every 3–4 weeks with a balanced liquid fertilizer at half strength through the growing season. Container plants need feeding more often, roughly every two weeks, since frequent watering flushes nutrients away. Avoid heavy nitrogen, which produces lush leaves with diluted flavor and aroma. If you're harvesting heavily and continuously, modest steady feeding keeps the plant pushing fresh, tender growth rather than tiring out.

Pruning & maintenance

Pruning is the secret to a big, bushy basil plant and a long harvest. Once a seedling has several sets of leaves, pinch the top growth just above a leaf pair to trigger branching; repeat regularly. Always harvest from the top down, never stripping the lower leaves. Crucially, pinch off flower buds as soon as they appear — once basil flowers (bolts), it diverts energy to seed, leaves turn bitter, and growth slows. Frequent harvesting is itself the best pruning, keeping the plant compact, productive, and flavorful through the season.

Propagation

Basil is easy from both seed and cuttings. Start seed indoors 4–6 weeks before the last frost, sowing 1/4 inch deep in moist seed-starting mix kept around 70°F; seedlings emerge in 5–10 days. Grow under bright light to prevent legginess, then harden off and transplant after frost danger passes and nights warm. To propagate from cuttings, snip a 4-inch non-flowering stem, strip the lower leaves, and root it in a glass of water on a bright sill — roots appear within a week or two, then pot it up. Direct-sowing outdoors also works once soil is warm.

Through the year

Spring

Start seed indoors 4–6 weeks before last frost; harden off and plant out only once nights stay above 50°F.

Summer

Peak season — harvest from the top often, pinch off flower buds promptly, water evenly, and feed lightly to keep new growth coming.

Fall

As nights cool, harvest heavily before frost, and pot up a plant or take cuttings to carry indoors under a grow light.

Winter

Grow indoors in a warm room under bright supplemental light, or rest until spring and resow.

Companion planting

Classic companions: tomatoes, peppers, oregano; said to improve flavor and deter pests; keep away from rue and sage.

Recommended supplies for Basil

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The complete Herbs care library

Every species in one printable, organized reference — side-by-side care, a pet-toxicity table, and a seasonal calendar.

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