Basil- Thai Siam Queen

How to Grow Basil from Seed

Family: Lamiaceae
Binomial name: Ocimum spp.
Life Cycle: Annual

When to Sow Basil Seeds

Basil is a warm season crop. Use the table below to identify the best time of year to sow basil seeds in your climate.

Preparation

Basil plants are best grown in full sun. Choose a location that will receive at least 6 hours of full sun each day.

Basil plants need a well drained soil enriched with plenty of organic matter. Prepare soil by weeding it thoroughly, digging it over to loosen it and adding aged animal manure or compost. Keep the area free of weeds until planting.

Basil plants can be grown in containers. If possible choose a variety that’s recommended for container growing. Use a good quality potting mix and make sure your container is large enough for mature plants; a minimum of 10 litres is recommended for basil. During the growing season, keep in mind that container grown plants may need additional fertiliser to encourage healthy growth.

How to Sow Basil Seeds

Basil seeds do not require any treatment (eg soaking, stratification) before sowing.

Basil seeds can be sown directly into the garden OR seedlings can be raised in trays or other containers and transplanted to the garden once established.

Sow Direct

1. Sow seeds directly in the garden 2mm deep and 40cm apart.
2. Keep soil moist but never wet or dry.
3. Seeds should germinate in around 5-10 days at a soil temperature of 18-35°C.
4. Young seedlings will need protection from pests, pets and weather until they are established.

Raise Seedlings

1. Fill trays, punnets or jiffy pots with a good quality seed-raising mix, or use soil starter pellets.
2. Sow seeds 2mm deep.
3. Keep soil moist but never wet or dry.
4. Seeds should germinate in around 5-10 days at a soil temperature of 18-35°C.
5. Transplant seedlings to the garden once they have their first true leaves and are large enough to handle (usually 5-10cm tall).
6. Plant out, spacing plants 40cm apart.

Tip: Basil seeds can also be sown in the less formal ‘scatter seed’ method. Simply roughen the soil, scatter seeds evenly over the surface, then smooth the soil over lightly to cover the seeds.

How to Grow Basil

Basil plants need regular watering during the growing season. Water when the soil is dry about 5cm below the surface (test this by scratching away a little soil with your finger). Water deeply in the early morning or late afternoon. Avoid watering the leaves of plants to avoid fungal diseases. Learn more about watering here.

Optional: To give plants room to grow, thin seedlings when they are large enough to handle. Pull out any weak or small seedlings so plants are spaced about 40cm apart.

If soil was well prepared no extra fertiliser should be necessary. In poor soil or to give your plants an extra boost, application of a high-nitrogen fertiliser or one formulated for leafy greens or herbs can be beneficial:

• Apply slow release fertiliser at the recommended rate when transplanting or when seedlings are 5-10cm tall.
• Apply liquid fertiliser at the recommended rate and frequency during the growing season.

How to Harvest Basil

Basil should be ready to harvest in approximately 70 days.

Leaves are ready to harvest when they are large enough to eat, and can be harvested as needed. Harvest leaves by pinching off the outer leaves, leaving some on the plant for future growth. Eat leaves as soon as possible after harvesting. Store leaves short term in a perforated plastic bag in the fridge. For longer term storage, leaves can be frozen whole or chopped and frozen in ice cubes.

Common Problems when Growing Basil

Like all plants, basil is susceptible to some pests, diseases and other problems. Below is a list of the most common problems gardeners encounter when growing basil plants:

• 

  Whitefly is a sap-sucking insect related to aphids. They are often found in large numbers on the underside of leaves and will swarm in clouds when disturbed. Plants may have yellowing leaves or may wilt, and growth will be slowed. Whitefly can be removed with a garden hose or sprayed with soap spray. Badly affected plants should be destroyed. Attracting beneficial insects that will prey on whitefly can be beneficial. Read more about managing whitefly here.
• 

  Slugs and snails are molluscs that feed on tender leaves and shoots, mostly at night, leaving slimy trails behind them. Control them by removing their hiding places, keeping free range poultry, collecting them by torchlight or by placing traps. Read more about slugs and snails here.
• 

  Damping off is caused by a fungal growth that transfers from the soil to seeds or tender seedlings. Seeds may appear not to germinate, or young plants start to rot when they emerge from the soil and become soft and mushy at the base before dying. Use new potting mix if raising seedlings, do not water foliage and avoid waterlogged soil. Read more about damping off here.
• 

  Bolting is when a plant prematurely flowers and goes to seed. Bolting can be caused by a period of extreme weather. Avoid sowing seed until after the danger of frosts has passed or in very hot weather. Water plants regularly and deeply in hot weather to prevent them suffering heat stress.
• 

  Frost damage can cause leaves to wilt and go black. Do not plant seedlings in the garden until all danger of frost has passed in spring, and harvest plants before winter. Prune all frost-damaged leaves to avoid them rotting on the plant.