I use the Hydrofarm mat 20x48" I think its the biggest they make. Its a sealed mat so no problems with spillage and I've done it plenty of times. Also have it on foam sheets for better heat transfer. It does get a little cold in my basement so this year I may try building a mini greenhouse over it to try and mimic a greenhouse effect.
So far it definitely has helped my germination rate. I use it for all my veggies and even the wife's flowers and bulbs. Bought mine thru Amazon, best price around.
So far it definitely has helped my germination rate. I use it for all my veggies and even the wife's flowers and bulbs. Bought mine thru Amazon, best price around.