If the top tray doesn't have holes how is the water from the bottom tray going to 'wick' into it? I'm not understanding this set up. Can you explain further?

Manual just assumes you're cooking directly in the PC.

What you are describing won't work. The flat containing the pots has to float or be suspended above the flat holding the water.

All you need is a standard flat with no holes, a piece of capillary matting cut to fit it on the long sides of the flat but left longer in length so it can drape over into another container sitting end to end with the flat that contains your pots. Another flat filled with water works well. Simple and easy to do.

However you also need to understand that capillary matting has problems of its own. It tends to way over-water many plants, especially young seedlings. And it will wick water as long as water is available regardless of if the plants need it or not. Fill the water flat with water and you will come back later to find most all that water sitting over in the flat with the pots and the pots will be soaking wet.

The wicking material used in the commercial set-ups of this kind are much thinner than standard capillary matting, made of a different material, and do less wicking to try to avoid just this problem. They also use spnge type mediums rather than potting mix so they dry out faster. Even then they are only partially successful at eliminating the problem of over-watering.

Standard capillary matting works ok for well established plants that need to be left alone for a few days for some reason, They are old enough to tolerate the over-watering for a brief period of time as long as they are allowed to dry out some when removed from the matting. Germinating seeds and young plants are not so tolerant.

Dave