Irrigating ceramic beads

I’m using expanded ceramic beads only in an ebb and flow system and am concerned about getting enough water/nutrients to plants. Most books recommend watering twice a day, but that’s with spongy rockwool. Ceramic beads don’t hold much moisture.
I keep the lights on for 18 hours daily, from 6am to midnight. The plants are irrigated for 15 minutes at 7am, 11am, 3pm, 7pm and 11pm.

They were wilting a little before I changed the light from a 400-watt to a 1,000-watt high pressure sodium. Now they are wilting quite a bit. What should I do?


Use your eyes and your intuition. The plants are wilting because the roots are drying between irrigations. The solution is simple. Irrigate the plants more often. Start just before the lights come on, then every two hours during the lit period and every four hours during the dark.

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