So, you need to permanently keep water in the plant saucer.
Fill up the saucer with water and allow all the soil to become wet, filling the saucer up when it is low on water.
If you notice the water becomes discoloured it can be changed weekly.
How to grow watercress: As the name might suggest, watercress needs to be kept moist all year round (Image: The Watercress Company)
Try not to water over the top of the soil, as this can disrupt the seed.
Watercress does not need to be fed, however, you must make sure it stays damp.