Is it best to fertilize a plant the day before it rains?
Wayne County Michigan
Hello and thank you for using eXtension for your fertilization question. Yes, applying fertilizer before a rain is best for granular. if using a liquid you can apply anytime.
I believe with Hostas you should apply a granular after it rains to keep the slugs away. Is this different than for all other plants?
Yeah, slugs don't like salt and granular fertilizers are a type of salt. This only works until the rain dissolves the fertilizer into the soil. IF you have a slug problem i would look for something better to control them. Using fertilizers is dependent on soil quality. if you have your soil tested then you will know what you need for optimum plant health.