They sell 15 minute interval timers for aquariums. Pet stores sell them.

The ones I use are almost exactly like this one.

Plants in clay pellets can tolerate frequent watering. However, if you start clones in rockwool cubes, make sure the RW cube does not get flooded/dripped.



In drip systems, use a drip ring to assure that you're wetting the pellets but not the RW cube. Buy them assembled or make your own from a tee fitting and flexible tubing with a bunch of 1/8" holes drilled in it.



Plants in RW can only tolerate watering about 1x/day. Once the roots knit into the pellets, those new roots can handle frequent (such as 15on/45off in lights on) if not continuous drip cycles. Flood systems can be set for about 5x 5min floods per day.

While ordinary mechanical timers with 15 min increments can be useful, digital timers can be set for single minute runtimes with multiple programs per day.

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Get a harvest every 2 weeks - A batch of clones in rockwool - Al B. Gone