edible gardening
How to grow basil — indoor + outdoor beginner guide
Grow basil from seed or transplant: warm soil, 6+ hours sun, weekly watering, and pinching above nodes for bushy plants. Indoor + outdoor methods.
How to grow basil — indoor + outdoor beginner guide
Basil (Ocimum basilicum, most often the Genovese sweet basil cultivar) is the most-grown of the culinary types of herbs in US and UK home gardens — and one of the easiest IF you give it what it needs. The trick is heat: basil hates cold soil, cold air, and cold roots. Get those right and the rest is just regular pinching.
Set basil reminders in Growli: Add your basil variety to the Growli app and the morning briefing tells you when to pinch, when to feed, and when frost is coming.
When to plant basil
Basil is frost-tender. Cold soil stunts growth and cold air kills seedlings. Approximate timing:
| Region | Indoor seed-start | Outdoor transplant |
|---|---|---|
| US zone 3-5 | Early April | Late May / early June |
| US zone 6-7 | Mid-March | Mid-May |
| US zone 8-10 | February | Early April |
| UK southern | Mid-March | Late May |
| UK northern | Late March | Early June |
Soil temperature matters more than air temperature — basil germinates at 18°C+ (65°F+). Use a heat mat for indoor seed-starting in cool spring; our full starting seeds indoors guide covers the lighting, watering, and hardening-off routine.
From seed vs transplant
Seed (cheaper, slower):
- Surface-sow seeds in moist seed-starting mix.
- Cover with a thin layer of vermiculite (basil needs light to germinate well).
- Keep at 18-24°C; germination in 5-10 days.
- Pot up to 4-inch containers when first true leaves appear.
- Harden off for 7-10 days before transplanting outdoors.
Transplant (easier, faster):
Buy 3-4 starter plants from a garden centre in May. One household needs 2-4 basil plants for steady summer supply.
Light requirements
Basil is a sun-lover:
- Outdoors: 6+ hours direct sun. South-facing in UK, south or west in US.
- Indoors: The brightest window you have — south-facing minimum, or a grow light providing 12-14 hours/day of light. Indoor basil grown in dim light becomes leggy and weak.
Watering
Water when the top inch of soil is dry — typically every 2-3 days in summer, longer in cooler weather. Basil signals thirst by dramatic wilting; water within an hour and the plant recovers fully.
- Water at the base, not on leaves — wet leaves invite fungal disease.
- Mulch outdoor basil — retains moisture, suppresses weeds, keeps soil cool.
- Don't overwater — soggy soil rots basil roots fast.
Pinching for bushy growth
This is the single most important basil skill. Every 2-3 weeks once the plant is 6 inches tall:
- Find a node where two side shoots are forming.
- Pinch the top growth just above that node.
- Two new branches grow from that node within a week.
Repeated pinching doubles the harvest. See the dedicated how to prune basil guide for the full method.
Flower removal
The moment basil shows flower buds, pinch them off. Once basil flowers, the plant shifts energy from leaves to seeds and the leaves turn bitter. Removing buds keeps the plant in leaf-production mode all season.
Feeding
Light feeding only. Quarter-strength balanced liquid fertiliser every 2-3 weeks during active growth (spring + summer). Heavy feeding produces lush leafy plants with weaker flavour.
Container vs in-ground
| Setting | Pros | Cons |
|---|---|---|
| Container (5+ inch pot) | Movable, brings indoors at first frost, easy to manage | Daily watering in summer, more feeding |
| In-ground | Lower maintenance, larger plants | Frost-end-of-season, slug exposure |
| Indoor (year-round) | Year-round fresh basil if light is adequate | Light is the constant limiter |
Indoor year-round basil rarely lasts past 3-4 months even with grow lights — plan to restart from cuttings or new seeds every season.
Common problems
- Yellowing leaves — overwatering. Let soil dry; resume normal schedule.
- Black spots — fungal disease, usually downy mildew. Remove affected leaves, improve air circulation, water at the base only.
- Leaves curling — heat stress or transplant shock. Move to partial afternoon shade in extreme heat.
- Slow growth — soil too cold or insufficient light. Move to brighter/warmer spot.
- Flavour weakening — flowering. Pinch all buds immediately.
Related articles
- How to prune basil — the pinching method in detail
- How to grow tomatoes — basil's best companion plant
- How to start a vegetable garden — bigger-picture beginner guide
- USDA zone & frost-date lookup — for timing transplants
Reviewed and updated by the Growli editorial team. For questions about anything here, open Growli and ask — or email hello@getgrowli.app.
Frequently asked questions
How long does basil take to grow?
From seed: 5-10 days to germinate, 4-6 weeks to first harvest, 8-12 weeks to a full bushy plant. From transplant: first harvest in 2-3 weeks, full plant in 6-8 weeks. Outdoor basil hits peak production in July-August in US and UK climates.
How to grow basil indoors?
Use the brightest spot you have — south-facing window with at least 6 hours of direct sun, or a grow light for 12-14 hours daily. Water when the top inch is dry, feed lightly every 2-3 weeks, and pinch above leaf nodes every 2-3 weeks to keep bushy. Indoor basil usually lasts 3-4 months before becoming leggy.
How to grow basil from seed?
Surface-sow seeds in moist seed-starting mix and cover with a thin layer of vermiculite. Basil needs light to germinate well. Keep soil at 18-24°C (65-75°F) and germination happens in 5-10 days. Pot up to 4-inch containers when the first true leaves appear; transplant outdoors after the last frost.
How to grow a basil plant from a store-bought transplant?
Repot into a 5-inch container with fresh potting mix immediately — store basil is usually crammed into tiny pots that exhaust nutrients in days. Place in full sun, water when the top inch is dry, and pinch above nodes weekly to encourage branching. A well-managed transplant outproduces a seed-grown plant for the first 2 months.
How to grow basil at home year-round?
The honest answer: it's hard. Basil needs 12+ hours of bright light and warm temperatures. In winter, even south-facing windows in the US northeast and UK midlands don't provide enough light. Use a grow light, restart from cuttings every 3-4 months, and accept that summer harvests will be stronger than winter ones.
How to grow basil in a pot?
Use a 5-inch container minimum (10-inch ideal) with drainage. Fill with quality potting mix. Place in 6+ hours direct sun. Water daily in summer, every 2-3 days otherwise. Feed at quarter-strength every 2 weeks. Pinch above nodes every 2-3 weeks. One large pot supports 1-2 plants well — don't overcrowd.
How to harvest basil so it keeps growing?
Always harvest by pinching whole stems above a node, not by picking individual leaves. Each pinched stem causes the plant to branch from the node below, doubling leaf production. Aim to remove the top 30-40% of growth at each harvest, every 2-3 weeks during active growing season.
How does Growli help me grow basil?
Add your basil to Growli and the app sets pinching reminders every 2-3 weeks, watering reminders calibrated to your local weather, and frost warnings so you can bring container basil indoors before damage. Photograph any disease symptoms and Growli walks you through diagnosis and recovery.