Summary

Watercress is a sun and water loving perennial that grows naturally along running waterways. Watercress has a preferred pH range of 6.5 to 7.5. The plant does well in varying soil conditions provided the soils stay saturated with water. If you have a water feature in the garden, this is a good place to grow watercress. Otherwise, a potted watercress plant can be grown in a bucket to simulate the saturated conditions of a stream. The leaves and shoots are cultivated for their culinary and medicinal uses. The peppery taste of watercress has become very popular, especially in Europe as a salad mix. Flavor is best during the cooler parts of the year and the plant is hardy enough that it can be harvested throughout the winter. After the plant blooms, the flavor of watercress decreases in potency.

Recommended Watercress Varieties

Plants commonly called cresses include the fast-growing annuals Garden Cress, Curly Cress or Peppergrass (Lepidium sativum); the biennial Wintercress (Barbarea vulgaris) which grows in drier areas and produces a white flower, and the perennial Watercress or Big Leaf Cress (Nasturtium officinale). You can purchase watercress seeds or transplants of known varieties from reputable nurseries or from on-line sources and better seed catalogs.

How to Grow Watercress

Soil

Watercress grows best in wet, organically rich soils and tolerates a wide range of pH. If growing in containers use a soilless potting mix containing perlite or vermiculite mixed with peat. When growing in pots, keep the potting mix moist by having the pot sit in a saucer filled with water.

Soil Preparation

Before planting, determine fertilizer needs with a soil test and then follow the recommendations given with the test report. If fertilizer applications are warranted, work the fertilizer into the top 6 inches of soil. If you fertilize with compost, apply no more than 1 inch of well-composted organic matter per 100 square feet of garden area.

Plants

Watercress is easily propagated by stem cuttings or from seeds. Seeds should be sown just below the soil surface, about ¼ inch deep, roughly three weeks before the frost-free date for your area. Do not let the soil dry out as watercress requires wet soil for best germination.

Planting and Spacing

Plant watercress in a sunny location. Stem cuttings root quickly in rich soil along stream beds and creeks where the soil stays very wet. Seeds can be germinated indoors or outdoors under cool (50 to 60°F), wet conditions. When transplanting, space plants 8 inches apart and place them outdoors after the last frost. If growing in a container, thoroughly saturate the media prior to seeding or transplanting.

Water

Watercress is an aquatic plant that grows best in submerged or shallow moving water. In the garden, place potted plants in a bucket with 2 to 3 inches of water so the media stays wet and the roots are submerged under water. It is best to change the water once or twice a week. You can also plant watercress by an existing water feature in the yard, locating the plant where the soil stays saturated with water.

Fertilization

Watercress does not have a high nutrient requirement. However, cultivated watercress may show phosphorus, potassium or iron deficiencies. Phosphate deficient plants are stunted and dark colored. Symptoms of potassium deficiency are marginal scorching on older leaves. Iron deficient leaves, common in the winter, are expressed as yellowing between the veins on the newer foliage. Mixing a complete soluble fertilizer with the water at the recommended rates minimizes these problems.

Problems with Growing Watercress

Weeds

Keep area around plants free from weeds and mulch lightly to assist in maintaining moist soil conditions.

Pests

Watercress has no specific disease problems in most production settings. However, white flies, spider mites or snails are some of the more common insect problems. White flies are found underneath the leaves and can be controlled with soapy water or insecticidal soap. Spider mites cause flecking, discoloration and scorching of leaves. Injury can lead to leaf loss and plant death. Natural enemies of these pests include small lady beetles, predatory mites and predatory thrips. Snails can be removed by hand, controlled with a molluscide, or trapped. Always follow labeled directions when using any herbicide, pesticide or fungicide.

How to Harvest and Store Watercress

Harvest dime sized dark green leaves at any time during the year. Leaves and young stems taste best if harvested before watercress flowers. The peppery flavor is best when harvested in the cooler spring and fall. The flavor deteriorates as temperatures increase above 85°F. To harvest, cut the plant back to 4 inches tall, then let the plant re-grow for a fall harvest. Gathering watercress from the wild is not recommended as pollutants have been reported to cause illness.

Watercress can be harvested year round. Harvest what you can use in one meal. If needed, the leaves can be refrigerated for about a week. Watercress is high in iron, calcium and folic acid and is rich in vitamins A and C.

Watercress Uses

Harvested leaves are used in salads and soups, potato dishes or chopped to flavor butter blends and fish sauces. Many herbs are used for their claimed health benefits. For more information on herbal medicines, refer to a reliable information source for details on the benefits or hazards to using an herbal medicine. One such source is the National Institutes of Health’s herbal medicine Web site: http://www.nlm.nih.gov/medlineplus/herbalmedicine.html

Additional Resources

• Lesley Bremness. 2002. Smithsonian Handbooks: Herbs. Dorling Kindersley Publishing, 304p.

Published April 2020
Utah State University Extension
Peer-reviewed fact sheet

Authors

Trudy Kendrick and Dan Drost