Marble Hill Horticultural Soap What is horticultural soap? Horticultural soap is safe for the environment and used as an application to eliminate small soft-bodied insects such as aphids, whiteflies, spider mites, and mealybugs. Mix with Marble Hill Neem Oil in your own spray bottle. May be used either on indoor houseplants or on outdoor plants, including vegetables. Leaves no nasty residue, is non-toxic to animals and birds, and does not harm beneficial insects. Safe for the environment Garden and houseplants Multi-Use Horticultural Liquid Soap 750ml New Bigger Size Concentrated for Horticultural Use Taking care of pests in the garden doesnt need to be expensive or toxic. Horticultural soaps are a great way to combat many issues in the garden without harming the environment or your pocket.