How to Grow Water Cress Seeds

Grow Guide #2479
Family: Brassicaceae
Binomial name: Nasturtium officinale
Life Cycle: Perennial

This 'How to Grow' guide details everything a home gardener needs to know to plant, grow and care for Water cress (Nasturtium officinale).

When to Sow Water cress Seeds

Water cress is a perennial plant that grows year round in most climates. Use the table below to identify the best time of year to sow water cress seeds in your climate.

  JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
Cool
Temperate
Sub-Tropical
Tropical
Arid

Preparation

Water cress can be grown in fresh slow moving water such as a garden pond or stream, or in wet soil in the garden.

Water cress plants are perennial, meaning they live for several years. Choose a permanent position where plants can grow undisturbed by regular digging.

Water cress 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.

If growing in water, ensure the water is free of livestock and other animal waste; water cress can become infested with liver fluke if grown downstream of sources of animal waste. Liver fluke is a parasite that can pass to people when consumed, causing liver and bile duct disease with infection lasting up to 30 years.

If growing in soil, water cress plants need a consistently moist 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 seeds until planting.

How to Grow Water Cress in Water

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

Water cress seeds grow best when they are sprouted in water and transplanted into a pond or stream once they are established.

  1. Fill a shallow saucer or container with water.
  2. Sprinkle the seeds over the container.
  3. Place the container in a position in part sun.
  4. Refresh the water as needed; water cress requires clear, fresh water to grow well.
  5. Seeds should germinate in around 12-15 days.
  6. Transplant seedlings to a pond or stream once they have 4-6 true leaves and are large enough to handle.

Water cress plants may die back in cold weather. Cut plants back in late autumn, or prune off dead foliage when new leaves emerge in spring.

How to Grow Water Cress in the Garden

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

Water cress seeds grow best when they are raised in trays or other containers and transplanted into the garden once they are established.

  1. Fill trays or punnets with a good quality seed-raising mix.
  2. Sow seeds 3mm deep.
  3. Submerge the container in water to half its depth.
  4. Place the container in a position in part sun.
  5. Seeds should germinate in around 12-15 days at a soil temperature of 8-15°C.
  6. Transplant seedlings to the garden once they have their first true leaves and are large enough to handle.
  7. Plant out, spacing plants 100cm apart.

Water cress plants can also be grown in containers. 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 water cress. Sit the container on a deep saucer so the bottom of the container is sitting in water. Change the water in the saucer if it becomes muddy. 

Water cress plants need constant moisture during the growing season. Water regularly and do not let soil dry out.

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 balanced fertiliser or one formulated for fruit and vegetables 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 while plants are fruiting or flowering.

Water cress plants may die back in cold weather. Cut plants back just above ground level in late autumn, or prune off dead foliage when new leaves emerge in spring.

How to Harvest Water cress

Water cress should be ready to harvest in approximately 50-60 days.

Water cress is ready to harvest when the stems have grown long enough to pick, and can be harvested as needed. Harvest by pinching off the outer stems and leaves, leaving some on the plant for future growth. Water Cress can be stored short term in a perforated plastic bag in the fridge, or the stems can be placed in a glass or jar of water to keep them hydrated. For longer term storage, water cress can be frozen and then added to pestos and soups.

Common Problems when Growing Water cress

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

  • Aphids
    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.
  • Spider mites
    Spider mites (Tetranychus urticae), also known as two spotted mites, are sap-sucking arachnids that cause dry, wilted or discoloured leaves. The undersides of leaves may feel dry and a little like fine sandpaper. Prune plants to allow good air flow or spray with eco-oil or wettable sulphur. Learn more about managing spider mites here.
  • Whitefly
    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.

Browse Water Cress Seeds

Water Cress
SOW NOW 
SOW NOW 
SOW SOON
SOW SOON

Water Cress

Packet 500 seeds

$1.50

Add