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.
- 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.
- 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.
- Harvesting can be done throughout the season which will ensure the plants don’t go to seed which diminishes the flavour.
- Harvesting can be done after 3-4 weeks, cutting back to 4 inches high. This will thicken and strengthen the plants.
- Cutting should be done with a scissors.
I’m also going to give you some other general pointers, see below.
- Watercress can be propagated by seeds, transplants or cuttings so if you overharvest or your current planting expires, you can sew more seeds.
- Seeds germinate in a cool environment – 10-15 degrees C is ideal.
- The planting area needs to be kept moist, not wet, so a spray bottle and water is best for maintaining an even moisture level.
- Seedlings should appear in 5 days – I week. They should grow fairly rapidly and be ready for their first harvest in 3-4 weeks.
- 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.
- Transplants should be planted/spaced 8 inches apart.
- 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.
- 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.