ent, will not significantly affect the moss-killing ability of this product. Wait several days until moss turns black and dies, then gentle rake it out. Step 3: Reduce Soil Acidity – Since grass may be slow to fill in bare spots, reseeding of treated areas is recommended. To reduce acidity, which may contribute to moss growth, apply a lime mineral supplement. Apply lime anytime-before, during or after moss control treatment. Spot Treat Moss Around Ornamentals, Shrubs & In Flower Beds 1.