In general, an orchid needs water once a week. You can tell whether the orchid is thirsty by looking at the color of its roots. If the roots are grey, the plant needs water. If the roots are green, the orchid is doing perfectly fine. When the roots are grey, you can submerge the nursery pot in a shallow layer of water for about 10 minutes. This gives the roots enough time to absorb moisture. Afterwards, let the orchid drain well and place it back in its decorative pot. Tip: preferably use rainwater instead of tap water, as tap water usually contains a lot of lime.