When and how often to flood?

that sounds like a good amount..... try it. you'll be able to tell if they aren't getting enough,

Watering interval depends on the medium, how that is contained (in pots?), size of plants and so on.

Judging watering by weight is good for absorbent media like rockwool, not so good for non-absorbent stuff like clay pellets.

ok..yeah in pots..I'm thinking 2.5-3 gallon..maybe with perlite and hydroton mix? Flood up to 1/2 or 3/4 of the container for 20 minutes and drain...but how often or how do i tell??

for that arrangement, should be OK to flood 3x/day to start, might be 4-5x/day in weeks 3-6 if plants are well developed. Flood up to the overflow level and shut down the pump, however long that takes for your pump & tray.

Short flood times are better than long. The water draining back will draw oxygen through the pellets. You can always flood again later if they need more water. The worst way to tell if they need more water is if they are wilting, but it also happens to be the surest way.

If you use short, frequent floods in pots of pellets alone, you won't have any trouble with overwatering symptoms. Very hard to overwater pellets alone.

Mixing in some perlite will increase the water holding capacity which is good if you want some water held in reserve in case of a pump or timer failure, but you don't need to water as often. Perlite is a puffed glass that has a lot of airspaces so it's pretty hard to overwater, but I imagine you could if you tried hard enough. .

That sounds easy enough..thanks for the info