NeonTetra
Member
TL;DR -- Is it OK if the pH of your medium changes from the bottom to the top?
Does anyone have experience with pH gradients in their medium? I'm running continuous NFT. My plants are in 5" net-pots. I transplanted them in to 3" rockwool cubes (probably won't do this next time), and now have the cubes in the netpots packed with hydroton, including a 1" layer of hydroton at the bottom of the net pot. (Next time I'm sticking to 1" cubes and transferring direct to hydroton, but anyway...)
I now have a relatively high percentage of rockwool-to-hydroton. I'm keeping the pH of my reservoir at 5.8. I sample water off the top of the rockwool cube and it's at a pH of 6.4. My roots are just now peaking out of the net pot. I have this gradient with the water rushing underneath at a pH of 5.8, and moving up the medium the pH climbs to 6.4.
On one hand I can see this being beneficial. The upper root system sits at one end of the beneficial pH spectrum so has higher absorption of nutrients on that end, while the bottoms (and eventually the bulk) of the roots will sit at a pH of 5.8.
Plants look great, but it's only been 24 hours or so. Has anyone seen detrimental effects of such a pH gradient? Or is this beneficial? I have an integrated top-feed system, so I could periodically drip the pH 5.8 water through the top to shift that gradient down a bit. I can also drop the pH of my res until more of the root mass is in the NFT stream.
Does anyone have experience with pH gradients in their medium? I'm running continuous NFT. My plants are in 5" net-pots. I transplanted them in to 3" rockwool cubes (probably won't do this next time), and now have the cubes in the netpots packed with hydroton, including a 1" layer of hydroton at the bottom of the net pot. (Next time I'm sticking to 1" cubes and transferring direct to hydroton, but anyway...)
I now have a relatively high percentage of rockwool-to-hydroton. I'm keeping the pH of my reservoir at 5.8. I sample water off the top of the rockwool cube and it's at a pH of 6.4. My roots are just now peaking out of the net pot. I have this gradient with the water rushing underneath at a pH of 5.8, and moving up the medium the pH climbs to 6.4.
On one hand I can see this being beneficial. The upper root system sits at one end of the beneficial pH spectrum so has higher absorption of nutrients on that end, while the bottoms (and eventually the bulk) of the roots will sit at a pH of 5.8.
Plants look great, but it's only been 24 hours or so. Has anyone seen detrimental effects of such a pH gradient? Or is this beneficial? I have an integrated top-feed system, so I could periodically drip the pH 5.8 water through the top to shift that gradient down a bit. I can also drop the pH of my res until more of the root mass is in the NFT stream.
