Mine has a seperate removable drip mat for the base,Gran,which soaks up any unwanted water from the pots, and no,you don't want trays without drainage holes,as your seeds etc,need drainage or they will rot..If you didn't get a drip mat,which also helps with bottom heat from your propagator,you can buy one ,or use a similar thing,,like material you use in hanging baskets ? If it gets too wet,you can just wring it out,and put it back..hope this helps..

What I do is put about 2" of horticultural grit in the bottom of the propagator, and just stand the pots and trays on this, just normal trays with drainage holes, any watering you have to do will not come into contact with any electrical parts, they are well insulated for use in greenhouses etc.

I put about 1cm of silver sand on the bottom of mine then just stand pots and trays on top.

Thank you all very much. I have accessed many web sites and books but this forum is definitely the best for answering questions immediately with practical help and advice.