Gnats can be rid of with sand to cover topsoil, make sure your bucket drain holes get covered after watering. Yellow sticky cards will get rid of adults. Sand stops them from laying eggs. If you are using saucers with containers make sure not to leave standing water. The real secret sauce is making sure you let your soil dry out between watering in the future. Gnats eat bacteria in soil and are attracted to wet soggy soil and dead decaying things.
If I put sand over the top soil would it still be ok to water it Idk if this sound dumb but soil an sand I would think drain different Sent from my iPhone using Grasscity Forum