Watercress in a pot


Hi, we just bought a Watercress plant and planted it in a pot, for the first time. What kind of soil do you recommend? We used Promix organic vegetable and Herb Mix, is that a good choice? What type of fertilizer do you recommend and how often do i fertilize? Can i harvest watercress through to the fall or should i start seeds in a pot to ensure continuous harvest? When should i start to pick for eating, at a certain height? Should i cut with scissors? thanks very much! Marlene


I’m going to answer your questions in the order in which you asked them, see below.

  1. A good quality potting soil designed for container use is ideal.  To this mix, your watercress would benefit from the addition of some organic matter such as compost.
  2. Watercress can be deficient in iron, potassium and phosphorus so feeding a complete soluble fertilizer is a good idea.  You can use a 10-10-10 or 20-20-20, and following the application instructions on the package carefully is advised.
  3. Harvesting can be done throughout the season which will ensure the plants don’t go to seed which diminishes the flavour.
  4. Harvesting can be done after 3-4 weeks, cutting back to 4 inches high.  This will thicken and strengthen the plants.
  5. Cutting should be done with a scissors.

I’m also going to give you some other general pointers, see below.

  1. Watercress can be propagated by seeds, transplants or cuttings so if you overharvest or your current planting expires, you can sew more seeds.
  2. Seeds germinate in a cool environment – 10-15 degrees C is ideal.
  3. The planting area needs to be kept moist, not wet, so a spray bottle and water is best for maintaining an even moisture level.
  4. Seedlings should appear in 5 days – I week.  They should grow fairly rapidly and be ready for their first harvest in 3-4 weeks.
  5. Plant pots should be placed in a saucer which should always be full of water so that the soil within the pot maintains an even moisture level.  So a 15 inch pot should be placed in a 17 inch saucer which is at least 2 inches deep.
  6. Transplants should be planted/spaced 8 inches apart.
  7. If you are placing your pot outside, a 1 inch layer of mulch applied to the soil surface is recommended in order to minimize evaporation.
  8. Pests outside include snails, white flies and spider mites.  Snails can be hand picked off, while white flies need a spray of insecticidal soap and for spider mite control, you may need to invest in some ladybugs or predatory mites.

Good luck and Enjoy.