2 mediums, 1 strain. leaves cupping. wtf?

TheJointProject

Well-Known Member
About 3 weeks ago I transplanted 2 freshly rooted C99 clones into 2 separate grow mediums, one into a 1 gal. pot of soil and perlite and the other into a 5 gal DWC bucket with hydrotron and 2 3.5volt air pumps each connected to an 8 inch airstone. Each received straight water right after the transplant, then I shot them with ½ strength GH 3 part nutes, along with ½ strength Cal-Mag. Soon after I started to notice some cupping on a few of the leaves on the one in the DWC. The next day the same thing started to happen to the one in the soil. I changed out the DWC res and filled it back with straight water again and gave just straight water to the soil one on its next feeding. It soon cleared up and both started to grow nicely again. I then decided to cut out the Cal-Mag and feed them both just ¼ strength GH 3 part flora. Water had a ph of 6.5. Be damned if they both didn’t start cupping again. I don’t have any idea what’s going on here. I’ve used the exact same nutes for 2 other successful grows of the exact same strain from the same mother by simply following the feeding schedule on the bottle @ ½ strength and had no problems. All my water has stayed between 5.8 and 6.5 for the most part from the start. The room temps never reach higher than 75*F during lights on at the canopy level so I know it’s not a heat issue. I havn’t given them much of anything as far as nutes go so I doubt it’s salt buildup. neither one received cal-mag the second time so that pretty much rules out mg toxicity. They are under a 400w MH vented with a 250 cfm fan into the attic and I can touch the glass and it’s not hot. The growing room is 3ft wide x 5ft long x 6.5ft high and has a dedicated 9000btu air conditioner for the room.

I’m still a little new to the DWC world so I expect to screw that one up a little as a learning curve. That’s why the other one is in the soil. I could really use some help with this one guys. What else could be causing my leaves to cup like this? Other than the cupping both girls are growing very strongly and look good. +rep for a hand with this. Thanks.
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trance

Active Member
I don't work with DWC, so can't help you there really bud. But what I would say is check the sticky for uncle ben's moisture stress.

Whats your humidity and temps like?
 
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