How to sow basil?

Basil is an essential aromatic herb for both the garden and the kitchen windowsill. Its fragrant leaves enhance salads, marinades, and pesto. Easy to grow, sowing basil is within reach of all gardeners, even without a garden, as it thrives in pots or planters.

Follow our step-by-step tutorial to learn how to successfully sow basil, whether in pots or directly in the garden soil!

When to Sow Basil?

Basil can be sown in various ways. You can sow basil seeds indoors with warmth, under unheated cover, or directly in the ground. The sowing period varies depending on the method used.

Warm Sowing of Basil

You can start sowing basil from February to April indoors near a sunny window or in a heated mini greenhouse. Keep them indoors at a suitable temperature (it needs above 20°C to germinate). Transplant the strongest seedlings outdoors once all risk of frost has passed. Allow about 2 months from sowing to outdoor planting. After 2–3 weeks, seedlings from warm sowing will need hardening off: gradually acclimatise them to seasonal temperatures by placing them in direct sunlight during the day and bringing them indoors at night to protect them from chilly evenings. They can then safely be planted outside.

Indoor basil sowing

Cold Frame Sowing

Late sowings in April–May can be done in a cold frame.

Direct Sowing in the Ground

Basil is an annual plant sensitive to frost. Plant it outdoors in the garden or in pots only once heavy frosts are no longer a risk, typically after the Ice Saints (mid-May), depending on the region and climate. Wait until temperatures warm up. From May to July, you can sow basil directly outdoors without worry.

My tip: Stagger basil sowings every two months to ensure tender young shoots until early autumn.

Direct sowing in the ground is best done around mid-May

Required Materials

Depending on your chosen method, you will need:

• A mini greenhouse or biodegradable seed trays
• Biodegradable pots or plastic bottles
• Good-quality seed and potting compost
• A spray bottle
• Scissors or a cutter for cutting bottles
• A sharp knife for making holes
• A hand hoe for marking seed rows
• A trowel for transplanting seedlings
• A hand rake

How to Sow in Pots, Trays, or Bottles?

For seedlings to transplant into pots or the garden! Avoid sowing seeds too deep, as they need light to germinate.

Sowing in Pots

• Step 1: Fill pots with compost and lightly firm
• Step 2: Make 2–4 holes per pot
• Step 3: Place 2 seeds per hole, pressing them 3 mm deep with your finger (up to 5–10 seeds per pot)
• Step 4: Cover with compost
• Step 5: Water with a spray bottle
• Step 6: Place in a mini greenhouse or cover to retain moisture, warmth, and allow light through

Sowing in Trays

• Prepare trays by filling them with seed compost
• Sow seeds sparingly, spacing them a few centimetres apart
• Cover with a 1 mm layer of compost
• Water thoroughly with a fine spray to moisten the substrate
• Keep moist (not too wet or dry) until germination
• Cover (with a transparent lid, plastic bag, glass, cling film) to aid germination
• Place in a bright spot but out of direct sunlight, at a minimum temperature of 20°C
• Ventilate regularly
• Monitor to prevent damping off
• Once seedlings have at least three true leaves, transplant them carefully into individual pots

Sowing can be done in a tray with a lid acting as a mini greenhouse

Sowing in Bottles

• Cut a 1.5-litre plastic bottle in half horizontally, keeping the lower part
• Poke 3–4 small drainage holes in the base with a sharp knife
• Fill the bottom third with clay pebbles and moisten with water
• Fill halfway with seed compost
• Moisten the compost
• Place 2–3 basil seeds, spaced 2 cm apart, on the surface
• Cover with about 5 mm of compost
• Firm lightly
• Place near a heat source at 20–25°C
• Once seedlings are well developed, remove the root ball (cutting the bottle if needed) and transplant into the ground or pots, keeping only the strongest plants

Transplanting

Germination takes 10–15 days. When seedlings are well-rooted and about 5 cm tall (once true leaves appear), it’s time for intermediate transplanting into slightly larger pots filled with compost if outdoor planting isn’t yet possible. Wait until plants reach 10 cm (4–6 leaves) before planting them directly in the garden. Keep them under a warm cloche, watering regularly. Transplant young plants into the garden using a trowel, spacing them 20 cm apart, or into pots, containers, or planters filled with vegetable and herb compost, enriched with compost if needed. Transplanting basil can be tricky, so I recommend sowing in biodegradable pots to keep roots intact during transplanting. They also help retain watering moisture.

Basil can also remain in pots for easy kitchen access.

Transplant when basil has developed true leaves

How to Sow Basil Directly in the Ground?

Choose a warm, sunny spot (partial shade in hotter regions), sheltered from wind, with loose, moist soil enriched with compost. Loosen and weed the soil before sowing.

• Loosen the soil without turning it, using a broadfork
• Remove large stones and roots
• Level the soil with a rake

Sowing in Rows

You can sow basil in rows, for example between tomato plants:

• Step 1: Mark a shallow furrow with a hand hoe
• Step 2: Sow 1 seed every 5 cm
• Step 3: Cover with compost and firm with the back of a rake
• Step 4: Water lightly
• Step 5: Thin out when seedlings have 2–3 true leaves, leaving 25 cm between plants

Keep the soil moist during the first few weeks after sowing.

Thinned-out tomato and basil seedlings in the vegetable garden

How to Sow Basil in Pots?

If you don’t have a garden, sow basil seeds directly in planters or pots. Keep the pot warm indoors near a sunny window.

• Step 1: Add a 2–5 cm layer of clay pebbles
• Step 2: Fill three-quarters of the pot with vegetable compost
• Step 4: Press 2 seeds 3 mm deep with your finger, spaced about 2 cm apart across the pot
• Step 5: Cover with compost
• Step 6: Water lightly and keep moist until germination

How to Collect Basil Seeds?

In summer, basil produces spikes of small white or purple flowers, which, once pollinated, develop into tiny seeds. Once the flower stems are completely dry, the seeds will detach easily: cut the stems and shake them upside down over newspaper or a clean cloth. Store them until the following spring for sowing.