In the summer I planted some tamarind seeds in Aldi compost. They all grew
and are now approximately 1' high and have been brought indoors to sit on a
south-facing windowsill for the winter.

Unfortunately there now seems to be an abundance of small black flies
emerging from the pots (my fault for buying Aldi compost, I suppose). Is
there something I can drench the compost with to get rid of the little
bleeders?

Si