Greenhouses create the warm, humid environments that many species of plants need to survive. Unfortunately, white mold is also a plant, and it thrives in the moist environment inside a greenhouse. White mold is relatively easy to clean up. It is tougher to keep it from coming back. Reduce the environmental appeal by mopping up puddles of water left behind after watering, improving air circulation in the greenhouse and increasing sunlight penetration whenever you can.
Remove all of the easily portable items in the greenhouse--tools, gloves, plants, empty containers, everything.
Wash your work gloves, towels and any other washable cloth in the washing machine.
Examine the soil in your plants' containers. If you spot any mold, re-pot the plants with fresh soil. If this is not possible, scoop out the top inch of soil and replace it with fresh soil. If any of your plants have developed white mold, discard the entire plant and the soil that it was growing in.
Scrub away any visible mold on the surfaces in the greenhouse. Use a stiff brush dipped in a bucket of warm water to which a tablespoon of laundry detergent has been added. Then scrub all of the tools and other non-cloth items you removed from your greenhouse, except for the plant containers, with the detergent solution.
Wipe down all of the surfaces in the greenhouse, including the surfaces of the potting containers, with a rag dipped in a solution of 1/4 cup bleach mixed with 1 gallon of warm water. Wait 20 minutes, then repeat.
Wipe down all of the items you removed from your greenhouse with the bleach solution. Rinse off any metal tools immediately afterward; the bleach will corrode the metal if left in place.