Hi David, Welcome to All Things Plants.
You didn't say exactly what plants you are growing indoors and while some houseplants would do okay in the 10ºC/50ºF indoor temperatures, others would prefer it somewhat warmer than that; also, if the temp's fluctuate a lot the plants may not be happy trying to adjust from one extreme to another and it's not good to have them near drafty windows or doors either. You can raise the humidity around your plants by grouping them together and placing them on pebble filled trays with a small amount of water in the trays; adding more water as the level gets lower and evaporates.
I'm not sure what you mean by being an educator and having thousands of extra matches to stick into the plant pots but maybe someone else will understand that and be able to offer advice.
Again,
to ATP!
Lin
