How to Grow Cabbage from Seed
Family: Brassicaceae
Binomial name: Brassica oleraceae
Life Cycle: Annual
When to Sow Cabbage Seeds
Cabbage is a cool season crop. Use the table below to identify the best time of year to sow cabbage in your climate.
| JAN | FEB | MAR | APR | MAY | JUN | JUL | AUG | SEP | OCT | NOV | DEC | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Cool | ||||||||||||
| Temperate | ||||||||||||
| Sub-Tropical | ||||||||||||
| Tropical | ||||||||||||
| Arid |
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Preparation
Cabbage plants are best grown in full sun or part shade. Choose a location that will receive at least 3 hours of full sun each day.
Cabbage 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.
How to Sow Cabbage Seeds
Cabbage seeds do not require any treatment (eg soaking, stratification) before sowing.
Cabbage 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
- Sow seeds directly in the garden 5mm deep and 25-60cm apart, with rows 40-60cm apart.
- Keep soil moist but never wet or dry.
- Seeds should germinate in around 3-7 days at a soil temperature of 8-30°C.
- Young seedlings will need protection from pests, pets and weather until they are established.
Raise Seedlings
- Fill trays, punnets or jiffy pots with a good quality seed-raising mix, or use soil starter pellets.
- Sow seeds 5mm deep.
- Keep soil moist but never wet or dry.
- Seeds should germinate in around 3-7 days at a soil temperature of 8-30°C.
- Transplant seedlings to the garden once they have their first true leaves and are large enough to handle (usually 5-10cm tall).
- Plant out, spacing plants 25-60cm apart, with rows 40-60cm apart.
Cabbage is a cool season crop that will bolt in very hot weather. Do not transplant seedlings or sow seeds outside in very warm temperatures.
How to Grow Cabbage
Cabbage plants may need 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.
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 Cabbage
Cabbage should be ready to harvest in approximately 50-140 days.
Leaves are ready to harvest when a head has formed and the leaves are tightly packed. Harvest whole heads by cutting them at ground level. Cabbage can be stored short term in the fridge. For longer term storage cabbage can be fermented or pickled.
Non-head forming varieties can be harvested when the leaves are large enough to eat. Outer leaves can be harvested individually by cutting them at the base just above soil level. Alternatively, harvest the whole plant by cutting it at ground level.
Common Problems when Growing Cabbage
Like all plants, cabbage is susceptible to some pests, diseases and other problems. Below is a list of the most common problems gardeners encounter when growing cabbage plants:
Bitter taste can be caused by plants growing too slowly, suffering a setback in growth or being harvested too late. Enrich soil with aged manure before planting, ensure plants are watered deeply and regularly, and harvest when they are young and tender.
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.
Cabbage moth and cabbage white butterfly have white or grey wings with distinctive markings. They lay their eggs on the underside of leaves. Their caterpillars feed on the leaves, creating large holes and sometimes skeletonising the leaves. Use netting to exclude butterflies and moths or decoys to deter them. Pick the caterpillars off the plants or use an appropriate spray in a selective and targeted way. Read more about cabbage moth and cabbage white butterfly here.
Heads not forming is usually caused by warm weather or by growing plants too slowly, without adequate water or nutrients. Check to make sure you are growing a head-forming type of cabbage. In warm climates, grow cabbage in autumn and spring to avoid extreme temperatures. Water regularly and ensure adequate compost or fertiliser is applied.
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.
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.
