Haven't been making any terri's lately just seeing how they turn out and if they grow

I have seen some growth but very slow and now I have little bugs in the terrariums don't know what to do

I will be redoing the big one cause the little grass I used didn't grow the way I thought it would and it is building mold cause it was my first terri I had built. I did not put gravel or charcoal so mold is building. well thats what I get for not doing it the right way.