I started growing basil from seed indoors on my window about a month ago – the plant seems to be thriving in the recent sunshine with stems about 4 inches tall now. I have noticed a problem while watering and I can’t find a solution online. There appears to be a lot of tiny white pests wriggling around in the soil inside the pot. The same pests are in another pot beside it that has failed to produce any rosemary (which I also tried growing from seed). I used brand new seed compost from miracle grow for these. What could it be and most importantly, how should I get rid of it??? Thanks!
The pest is sciarid flies, commonly called mushroom flies. The eggs are laid in wet compost and hatch to small white larvae. These pupate and fly off. It is encouraged by over-watering and watering too often.
Try allowing the compost to almost dry out, your basil plants on the point of wilting. Always allow plants in pots to get slightly dry on the surface before watering.
The rosemary probably did not sprout because the compost was too wet. You would need to mix half coarse sand and half compost for rosemary to sprout.