How to Get Algae Out of Rockwool

Algae often grows on rockwool as plants germinate and establish themselves. Algae needs a warm, moist and sunlit environment to thrive and rockwool provides that. As long as the algae is green and growing, it does not pose a threat to the plants. However, when it turns black and dies off suddenly, it steals oxygen from the plant's roots and leaves it susceptible to bacteria and viruses. To get rid of the algae, you must make its growing environment less inviting.

White plastic
Scissors

Instructions

- 1
  Cut white, opaque plastic to a suitable size to cover the top and sides of the rockwool. Cut a hole or holes large enough to give the growing plant an inch of space around its stem.
- 2
  Cover the rockwool with the cut plastic. First place the circle over the seedling or hole in the plastic and drape the plastic loosely over the rockwool. Leave the bottom of the rockwool uncovered to allow drainage.
- 3
  Cut away and discard the plastic once the plant's leaves grow large enough to block out the light that reaches the rockwool.
- 4
  Cut back watering to allow the surface of the rockwool to dry out, once the plant's roots extend past the rockwool and directly into the solution. Allowing the surface of the rockwool to dry out between waterings will rob the algae of the moisture it needs to grow.

How to Kill White Fungus Dirt on a Household Plant

Care for Pandanus veitchii

Indoor Growing