EmeraldBuddah
Member
+rep please!
Great looking setup man, sorry to hear the plants are suffering slightly. I think the problem is exactly what you thought, over watered and a little hi on the nutes. The ones that are looking wilty just leave alone. sitting in their bucket is all they need. Also 500 ppm might be too hi for your plants. All strains are different and require a different amount of nutes so i can't speak of your strain specifically, but i have 5 different varieties growing at the moment both indica and sativa all of which are around 1 foot in height. My ppm was around 480 previously and i had to drop it to about 320-340 cuz my girls were getting a bit of nute burn. So ya, cut back on any topfeeding, just let them soak up what they need from their bucket, and try to lower your ppm. then just wait a few days and see what the new growth is doing. I would also recommend going with a simpler nute mix. Good luck and keep us updated!
Here's a little tip to tell if you are overfeeding or under feeding. If your PPMs raise over time (like yours, 470 to 500) you are over feeding, the plants are taking out more water than nutes causing PPMs to climb. If your PPMs drop over time you are underfeeding, the plants are taking out more nutes than water causing the PPMs to drop. If your PPM stay constant over time you are at the sweet spot, the plants are taking out the same amount of water and nutes.
Those curled leaves looks like heat stress to me, but it's obviously not if your room only gets to 74 F at the canopy. I don't know what plants look like when they are forced to endure water that is too cold, as I've never had that problem (I always have the inverse problem, water that is too hot). But that may be your problem, because your water is quite a bit too cold, like 10 degrees. You want a water temp of 68 F, plus or minus 2 degrees. 58 F is way too cold, and honestly I am surprised your sativas haven't keeled over dead from such cold water. Or maybe that 58 was just a typo and you meant 68.
I use tons of PVC in my grow and I have no problems with 'toxic gas'. My day time ambient temps in the veg room are 90 degrees. PVC is made for use with drinking water. You can stockpile PVC next to your grow and have no problems. Now wet PVC glue is a different story.