Indoor toms not come up

I sowed some indoor toms 2 weeks ago and they have been indoors in 20 degrees since. So far, from 3 varieties none have come up. Is this too early ? I did this last year with success. The soil keeps drying out and shrinking so I have to keep topping the moisture up.

You must keep the soil moist.

Letting it dry out and shrink is a no-no.

I sow mine in a small seed tray and pop them into a plastic bag. It needs no attention until you see the signs of the first one coming through.

If you can see one coming up - take it back out of the bag!  It will go weak and leggy.

Get them into a light place, keep them moist and stick some aluminium foil behind them to reflect more light.

Not if you keep them moist, if one's up, the others should be well on their way.

I'm not with you why they would go leggy and weak under plastic. Surely they thrive like this. Besides, that's why they do so well in greenhouses isn't it?

The humidity and extra warmth makes their growth too fast, plus their indoors.  Big big difference to a greenhouse with light coming in from all directions. But even in the greenhouse they can grow leggy if your not careful with temperature and crowding.