Answer: There's always a risk of bringing insects in when you bring your plants back indoors for the winter. Rinsing them off thoroughly before bringing them indoors will help; treating them to a tepid indoor shower a week later will help dislodge any insect eggs hiding among the foliage. A final step in preventing insects is to cover the soil surface with decoratative rocks or even a temporary cover of aluminum foil. Fungus gnats feed and breed in decaying organic matter and they love potting soil. Placing a barrier between the adults and the top of the soil will keep them from breeding. I wouldn't recommend using a lime and water spray on hibiscus - it will burn the leaves. Best wishes with your hibiscus!
Q&A Library Searching Tips