How to Grow Rocket from Seed
Family: Brassicaceae
Binomial name: Eruca sativa
Life Cycle: Annual
Two plants are known as 'rocket' but they are different species botanically. Rocket (Eruca sativa) is an annual plant and is also known as Arugula, Roquette or Salad Rocket. Wild Rocket (Diplotaxis tenuifolia) is a perennial plant and is also known as Perennial Rocket, Wall Rocket, White Rocket or Sylvetta. This guide is relevant to both types of rocket as they have similar growing requirements.
When to Sow Rocket Seeds
Rocket is a cool season crop. Use the table below to identify the best time of year to sow rocket 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
Rocket 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.
Rocket 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.
Rocket 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 20 litres is recommended for rocket. During the growing season, keep in mind that container grown plants may need additional fertiliser to encourage healthy growth.
How to Sow Rocket Seeds
Rocket seeds do not require any treatment (eg soaking, stratification) before sowing.
Rocket 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 4mm deep and 30-40cm apart, with rows 30-40cm apart.
- Keep soil moist but never wet or dry.
- Seeds should germinate in around 6-10 days at a soil temperature of 15-20°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 4mm deep.
- Keep soil moist but never wet or dry.
- Seeds should germinate in around 6-10 days at a soil temperature of 15-20°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 30-40cm apart, with rows 30-40cm apart.
Rocket only - Rocket is a cool season crop that will bolt in very hot weather. Do not transplant seedlings or sow seeds outside in very warm temperatures.
Tip: Rocket 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 Rocket
Rocket only - Rocket 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.
Wild rocket only - Rocket plants need regular watering during the growing season. Do not let soil dry out; keep soil evenly moist but not waterlogged. 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.
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 30-40cm apart.
How to Harvest Rocket
Rocket should be ready to harvest in approximately 30-60 days.
Leaves are ready to harvest when they are large enough to eat, and can be harvested as needed. Harvest leaves by cutting off the outer ones at the base, leaving some on the plant for future growth. Harvest small leaves regularly to avoid bitter tasting leaves and to encourage new growth. Eat rocket leaves as soon as possible after harvesting. Rocket leaves can be stored short term in a perforated plastic bag in the fridge.
Common Problems when Growing Rocket
Like all plants, rocket is susceptible to some pests, diseases and other problems. Below is a list of the most common problems gardeners encounter when growing rocket plants:
Aphids are small (2-4mm long) sap-sucking insects that congregate on the new shoots or the undersides of leaves. They can cause leaves to wilt or become discoloured, and also excrete honeydew which can attract ants and other insect pests. To manage aphids, remove them by spraying with a garden hose, apply a soap or alcohol spray, or encourage predatory insects to your garden. Read more about aphids 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.
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.
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.
