Hi I've bought seeds to grow adenium obesum ( mixed sort, I have one growing really well and another that's been sitting in limbo for a few weeks now, I'll attach a picture, my question is can I cover the soil with something as I keep getting black flies around them and I'm afraid they'll lay eggs and destroy them if they haven't already begun. I've never grown them before and I seen them in a botanical garden and loved the unusual look of them. There was 5 seeds but only two seemed to have worked. Any tips are also appreciated.