Fighting Mourning Gnats
By using an - otherwise good - advice from here, namely to fertilize flowers with coffee grounds, my geraniums have accumulated in peak form in the summer, but when I tried it on houseplants, I soon had everything full of small black flies!
At first I thought they were fruit flies, but then I saw that they came from the potting soil.
I took a cigarette, took the tobacco out of the paper and spread it a little on the surface of the earth. Then pour and after a few days there were no more flies!
