How to Grow Sweet Basil
On this page
Sow sweet basil once soil temperature reaches 20°C.
The short answer
- Site
- 6+ hours of sun, soil pH 6–7
- Biggest risk
- Grey mould
Core growing advice on this page is checked against named horticultural sources — see References.
Sweet basil (Ocimum basilicum)
Also known as: Basil, Common basil, Garden basil · 6 sources cited · Verified
Quick Facts
At a Glance
Diseases
Pests
Soil & Growing Conditions
Growth Stages
Harvest & Storage
Companion Planting
Pollination
Pollinating insects (bees and other flower visitors)
RHS: basil flowers are attractive/nectar-rich to bees and other pollinating insects if plants are allowed to bloom, though gardeners typically pinch out flower spikes to prolong leaf harvest -- a direct culinary-yield-vs-pollinator-value tradeoff documented by RHS.
Plan your Sweet Basil planting
Timing for Sweet Basil follows soil temperature and frost, not the calendar date. The Global vegetable planting calendar explains the method. To work out where it fits in your beds, sketch your plot in the free Garden Layout Planner.
Growing Sweet basil in another region
Sowing dates, frost timing and local advice differ by country. Use the guide for where you garden.
Sources
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Glasshouse trial: marigolds grown alongside tomato throughout the season significantly slow glasshouse whitefly (Trialeurodes vaporariorum) population growth over 48 days. Reducing marigold proportion and introducing other non-host plants (basil, nasturtium, Chinese cabbage) also reduced whitefly populations. "Emergency" introduction after high whitefly buildup was much less effective than season-long companion planting.
These 2 sources are specific to this region. The full list of 6 sources behind this guide (Cornell University (Cornell Vegetables, Margaret Tuttle McGrath, LIHREC), FAO EcoCrop, PLOS ONE (Conboy, McDaniel, Ormerod, George, Gatehouse, Wharton et al. 2019) and others) is in the references of our UK guide to sweet basil; they describe the plant itself, which is the same wherever it grows.
Frequently Asked Questions
What soil pH does sweet basil need?
A pH of about 6–7. That span reflects genuine variation between the authorities we cite rather than a single agreed figure — the References section lists each source's exact range.
What problems affect sweet basil?
Our data links 4 diseases and 3 pests to this crop. See the sections above for each one and how to manage it.
Plan next season before the problems start
This page gives you the thresholds; the planner turns them into your own calendar. It works from what you can observe and measure in your garden rather than from dates written for somebody else’s latitude.
Get the Global Garden Planner →Instant PDF download · Works in either hemisphere
How this guide is put together
The growing data on this page — sowing windows, pests, diseases, soil and site requirements — comes from named horticultural sources, listed in References below, checked against international horticultural research and extension sources. An automated pipeline assembles that verified data into the page you're reading: it selects which facts to lead with and builds the surrounding prose and layout. It does not invent a date, a source or a number — where a verified value for a field isn't available, the page leaves it out rather than guessing. A person reviews and publishes each page; nothing goes live unverified.
Related Problem Guides
Last verified 2026-09-02
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Where To Go From Here
Take this crop from reading into a written plan for your own beds.
Keep going
Plan the next step
Use the printable SoilCommander planner for your region to turn this guide into sowing dates, bed layouts and weekly garden tasks.