Start in suitable weather
Basil is sensitive to cold. Put it outdoors when local conditions are reliably warm and frost risk has passed, introducing it gradually to sun and wind. A sunny, sheltered position is a useful starting point; adjust if strong reflected heat stresses the leaves.
Use a freely draining container mix and check moisture regularly. Keep the root ball from drying out completely, but do not leave the pot standing in water. Growth and water use slow in cooler conditions.
Pick the growing tips
Once the plant is established, pinch or snip a soft shoot just above a pair of leaves. Leave healthy foliage to support new growth. Removing developing flower buds can help keep a plant producing leafy shoots.
A small, struggling transplant needs time to establish before repeated picking. Yellowing or damaged leaves are a prompt to check exposure and moisture, not proof that it needs extra fertiliser.
Reference
- RHS: how to grow basil (planting, care and picking).