How to grow watercress: indoors or in the garden
Learn how to grow watercress and you’ll have a steady supply of healthy, flavorful greens to add to salads and sandwiches.
Because it grows so quickly, watercress is often considered an ideal crop for children, but its pungent, peppery flavor is more likely to be enjoyed by adults. It’s the perfect first crop for beginners to add to their vegetable garden ideas, and will sow the seeds of home growing excitement.
Watercress is packed with nutrients, including vitamins A, C, and K, that will keep perfectly when you cut it fresh.
It’s also very space-saving, so even the smallest of homes can fit a tray of watercress. “It’s the perfect size to grow on the windowsill,” says Rob Smith, product development manager at Thompson and Morgan.
“The trick is small and often – sowing a 4×4 inch (10x10cm) patch every two weeks will keep you in fresh, cultivated watercress all season long – perfect for salads and sandwiches.”
Once you’ve caught the grow bug, learn how to grow microgreens for a diverse supply of quick and easy superfoods.
How to Grow Watercress Indoors
- First, choose a suitable container to grow your watercress in. “You can use a plastic container with a damp paper towel, or even use an old cup filled with damp cotton,” Smith says. Keep in mind that watercress generally grows best in the ground, so consider filling your tray with a light layer of compost. Alternatively, you can use a grow mat or felt.
- “Sprinkle watercress seeds over the surface of the pot,” says Chris Bonnett, owner of Gardening Express. Don’t be tempted to sow the seeds too densely or the seedlings will compete for space – keep a light dusting.
- It’s important that the growing medium doesn’t dry out, so to keep the moisture in, cover the pot with a lid or plastic wrap. If it needs watering, use a spray bottle.
- Place your watercress on a bright, warm windowsill.
- Watercress seeds tend to germinate in about 24 hours and the seedlings will soon be ready to eat. “You’ll harvest in 5-7 days,” says Bonnett.
- To harvest watercress, simply wait until it is at least 2.5 cm tall and cut it with scissors.
How to grow watercress in the ground
If you prefer taller, more mature plants, you will need to learn how to grow watercress in the ground. You can sow the seeds in the ground or include them in your vegetable garden container ideas.
- Prepare your soil by raking it until it is fine.
- “Sow watercress seeds into the ground in a block or row, close together,” says Bonnett.
- Lightly cover the seeds with potting soil and water well. Don’t let the soil dry out. When watering watercress, be careful not to drown the seedlings or let them become tangled in the soil – ideally use a water spray bottle or a watering can with a fine rose.
- Once the seedlings are 1 inch (2.5 cm) tall, thin them out to give them room to grow.
- Harvest watercress outdoors with scissors once the plants have reached 5-6 inches (12-15 cm).
Types of watercress
There are several types of watercress you can grow, so experiment with different seeds and see which flavor you like best.
Common or curly watercress grows very well indoors, as does mustard watercress.
“If you want to try a different type of watercress, try learning how to grow watercress outdoors,” Smith says. “Watercress, American Groundcress (similar to watercress, but easier to grow in a vegetable patch) or Greek Watercress can be grown outdoors in pots or in the open air and are great added to salads .”
Does watercress grow back once cut?
Usually, when harvesting watercress, you cut it close to the soil line. But if you leave half an inch on the seedlings when you cut them, you may find that the watercress regrows.
If you are growing watercress on a paper towel, however, there will be no soil to draw nutrients from, so you will have more success starting over.
If you have the space, there is nothing to lose by experimenting. If all else fails, it will only take a few days to grow a fresh new crop.
Where does watercress grow best?
Watercress grows best in moist soil. It takes a lot of sun for the seeds to germinate, so when growing indoors, place it on a sunny windowsill.
However, when growing outdoors, watercress can struggle to cope with high temperatures. “When watercress gets too hot and dry, it tends to bolt,” says Bonnett. You may find watercress a good crop to grow in a more shady area of the garden.