Hydroponic on a boat. Why is my ph constantly rising??

[Jule247]

[/img]Hi I'm pretty new to hydroponic and I thought I give it a shot. I'm having a kind of kratky set up. I'm growing in 100 mm pvc pipes. I know it's not a big reservoir but I'm living on a boat with not much space and not much power. So I was thinking to just refill the pipes but keeping in mind that I have to leave air roots exposte. But the water is constantly moving because of the motion. So I introduced my seedlings to the system. I made sure ppm is not to high and ph is around 6 (with my really small seedlings I reduced the nutrition in my solution) everything looks good and it seems that after a week all the little guys are happy. Is just that when I test my water the pH has risen to around 7.8 so I adjusted it bu next day it was up there again. And that's pretty much every day. And I don't think it's great the keep adding stuff to adjust it?!? And I don't think that just after a week the nutrition are already gone and that made the ph rise. Specially not with the tiny seedlings... can anyone please help.

[imafan26]

My guess, is because the nitrogen is being lost by uptake of the plants and by vaporization. It also could be losses of sulfur taken up by the plants. which is why you use the pH down.

Your reservoir is too small and you are mixing different kinds of plants with different ages. That automatically will cause problems. You usually don't mix plants of different ages because the more mature plants will suck up all the nutrients depleting the reservoir faster and the smaller plant roots will struggle to keep up. You have large plants like basil in a small reservoir. I would have set those larger plants up on a bucket instead. The easiest thing to do is to change the solution weekly as these different plants and ages are taking up the nutrients too fast and unevenly. If you plant, try to put plants of the same age and kind in each tube. Since the reservoir is so small, it won't be enough to grow out the plants without replacing the solution weekly. Use hydroponic formula suitable for the type of plant you are growing. Different plants have different needs.