New 3x3 DWC 42 site S.O.G Table ???

okay i got my 3x3 table lid made used fence planks and cut hole for 3in net pots then painted with flat white bath and kitchen non toxic paint got a 400w hps not doing all 42 site cause dont have that many clones lol only 19 at the moment my ? is how tall should my clone be before i flower cause there only like 3 in tall

I would say as early as weed 3. Maybe earlier if you want.

oh yeah height, my fault. maybe 6"
You can start flowering really young with a setup like that.

thanks appreciate the reply