On to the actually coco part of my reply. You're in for some good news; coco is one of the most diverse mediums in terms of PH.

Coco can operate under hydro, soilless, or soil ph ranges. Meaning it's total ph range stems from 5.2 - 6.8. However with that said once you pick a ph range you want to use then you need to stick with it. Constantly fluxuating PH can be a stressor to the plant.

I like to keep my PH around 5.7-5.8 just because coco is fairly inert and the roots do better in acidic conditions when in a medium that is inert. However if I accidentally mix up a batch of solution that is 6.0 I don't stress about it; but that is only because the nature of the medium. I want everyone to understand; even polishpollack that if I were growing in hydro then I would be a stickler about being EXACT on the ph I wanted.

I see you're running a drip system. When running a continuous drip system you must be sure to flush your medium at least once every 4 weeks. The reason being is salt buildup. Even though coco is an inert medium salt can still destroy the chemistry of the medium. Salt will create some very drastic ph fluxuations that you need to be aware of. A simple flush once every 4 weeks takes care of this. Transplanting is also recommended at this point.

Keep in mind that you can confine plants to a slightly smaller pot than you would in a soil grow as long as you're willing to water it more frequently. At the same time though.. you can't stay in the same pot forever. You will eventually have to transplant.

The quality of coco is also important. Many coco distributors make their coco through a steaming process. This typically isn't a big deal so long as you flush a few times and presoak your medium. Reason being is that steaming the coco helps to release nitrogen nitrates within the source of the medium itself. This is toxic to plants ad also messes with PH. Canna Coco is RHP certified and not steamed; therefore does not have this problem. This is what I use but you can use any brand coco so long as it's not steamed.

To be honest; your specific PH fluxuation does't seem to be coco related at all.

When you are refilling your resevoir where are you getting your water? You said tap water so I'm going to assume that it's STRAIGHT from the tap. When pulling water from the tap you have dissolved solids that can make it difficult to reach and maintain a proper PH. These dissolved solids can act as a buffer and will bring your PH back up until some of these solids evaporate off.

If possible try filling up water and taking the TDS/EC measurement... let that water stand for 3 days and take it again.

So long as you're below 300ppm on your tap water then you're probably fine.


Like others here have said. Your plant looks great and doesn't look sick to me. Tell your bf to stop being so paranoid. :hippy:
daihashi Reviewed by daihashi on . pH in hydroponics (auto-drip coco)??? I recently got my plants a hydroponic system, but keeping the pH level in it at 5.5 - 6.0 is really difficult. The water with nutrients in it is at about 6.8, and then we add "GHE pH down" which lowers it to 5.5 - 6.0. But after a few hours its back to 6.5. Could the problem be that the plants are eating up the nutrients and leaving the pH closer to clean water pH? :P And should i just leave the pH at 6.5 ? Oh btw, plants are just about 10cm tall, growing a bit slow compared to what i'm Rating: 5