Have imported a lot of Heuchera seeds to grow varities not available here. This is approx the 5th attempt... but 1st time in a bottom heat Prop Kit. Seeds have come up very sporadically, and look very very thin, green and straggly... I have a few outside in a tray, in the Winter sun and rain, and they look completely different to the Prop kit ones, but are all the same varieties mixed together...help... what is going on? TIA