Ahh now I know the ones, could be good for raising seed them put on the big one to keep them going.

I could have slept on mine if I had ever been kicked out to the shed, oh well he missed his chance

I've got those little 2 inch square black plastic pots - fits 20 of them (and a few kids white plastic yoghurt containers. Have yet to try the sealed take away containers as this is my first attempt and I will try them next (after my Digis burst with joy)

If your using a genuine Heat'n'Grow unit, they are definately designed to be used with the capillary felt WET.

Using it dry could possibly damage the unit over time, the unit would have to work heaps harder to achieve the desired temps when dry.

The moisture is needed to transfer the heat evenly to your pots/trays/containers etc.

I take my capillary felt completely out (just pop off that little silicon blob holding it down) and submerse it completely in a weak bleach/water solution for a few minutes.

Squeeze it out very lightly and place back into the unit.

As I mentioned, covering the felt in glad wrap stops the water evaporating away too quickly and it stays wet for quite some time.

edit

Thanks Lanna - have wet the mat, and am much happier - it got 4 days of dry

edit.