Trashedagain77 Posted December 31, 2023 Share Posted December 31, 2023 I used to do most of my growing in rockwool with good results, especially in terms of yields. I don't seem to see much mention of it on here so just wondering if I'm out of date, lol! Anyway due to a small space and lots of recent low yields in soil I'm planning on revisiting the grodan cubes and slabs, Canna hydro a+b base, rhizotonic and cannazyme. Any thoughts or opinions very welcome. Peace. 1 Link to comment Share on other sites More sharing options...
GSZZ Posted January 1 Share Posted January 1 I'm the odd one out in my group of friends - they all grow in rockwool cubes and/or slabs! Its deffo becoming more popular again, especially as big US firms use it as its cheap. 3 Link to comment Share on other sites More sharing options...
Aphatspliff Posted January 1 Share Posted January 1 Athena 3.0 ec start to finish in rockwool slabs is about as trendy as it gets at the minute! 4 Link to comment Share on other sites More sharing options...
Trashedagain77 Posted January 1 Author Share Posted January 1 Please could I ask the hydro crew what do you use for pH down? I'm in a hard water region and have just read negative things about using phosphoric acid as down. Apparently it holds onto the phosphorus in the plant and can be harmful. I've read that Nitric or Citric acid are better. Can anyone help with any further advice please. Thanks. Peace. 1 Link to comment Share on other sites More sharing options...
Saddam Posted January 1 Share Posted January 1 There's nothing wrong with using phosphoric acid, it's cheap and works well. You realise that phosphorus is the chemical element (P) in every NPK feed and PK boost formula? 1 Link to comment Share on other sites More sharing options...
Trashedagain77 Posted January 1 Author Share Posted January 1 7 hours ago, Saddam said: There's nothing wrong with using phosphoric acid, it's cheap and works well. You realise that phosphorus is the chemical element (P) in every NPK feed and PK boost formula? Thanks for your reassurance Saddam I have only ever used phosphoric as a pH down and never really considered or questioned its possible negative implications until I started ready much more experienced and knowledgeable growers opinions. I was planning on continuing to use phosphoric acid but would welcome any further suggestions from experience of others. Thanks again Saddam. Peace. Link to comment Share on other sites More sharing options...
catweazle1 Posted January 1 Share Posted January 1 (edited) 8 hours ago, Saddam said: There's nothing wrong with using phosphoric acid, it's cheap and works well. You realise that phosphorus is the chemical element (P) in every NPK feed and PK boost formula? It also creates insoluble phosphates, which can drop out of solution. If I was using that, I would pH the water first, so that it has done its job on the carbonates before adding the other nutes. Nitric holds pH better in water-style growing than *organic acids like citric, malic, vinegar etc. Edited January 1 by catweazle1 1 Link to comment Share on other sites More sharing options...
GSZZ Posted January 1 Share Posted January 1 Nitric acid is better for hard water cos it forms calcium nitrate and magnesium nitrate when it reacts with whats already in the water, calcium ntirate being part A of most nutrients anyway. Good hard water nutes typically reduce the calcium nitrate in part A, and make the nitrogen back up with nitric acid. 2 Link to comment Share on other sites More sharing options...
Aphatspliff Posted January 1 Share Posted January 1 I’ve got hard water. Never given it any thought about what ph down I use, always got the growth tech one which I’ve just had a look at and it turns out it’s phosphoric. Who does a good nitric acid ph down @GSZZ? 1 Link to comment Share on other sites More sharing options...
MrSlatersParrot Posted January 1 Share Posted January 1 I've often wondered why nobody uses hydrochloric for pH down, anyone know? 1 Link to comment Share on other sites More sharing options...
catweazle1 Posted January 1 Share Posted January 1 (edited) Just now, MrSlatersParrot said: I've often wondered why nobody uses hydrochloric for pH down, anyone know? You would be adding chlorine in macro amounts when it's meant to be a trace nute. Edited January 1 by catweazle1 1 Link to comment Share on other sites More sharing options...
GSZZ Posted January 1 Share Posted January 1 Just now, Aphatspliff said: Who does a good nitric acid ph down @GSZZ? Dutch Pro ph down grow is the only one readily available from grow shops. The bottle says 8% but I have a feeling its stronger than that - exercise caution when using nitric acid though, its pretty nasty stuff. To reitrate what I said earlier, good hard water nutrients already compensate for whats in the water, and soft water nutes don't have to, so its quite easy to overdo it and apply too much nitrogen if you're using nitric acid as pH down, especially in flower. It really excels where you can actively reduce the calcium nitrate, with wet nutrients thats quite wasteful to do because you buy them together. 2 Link to comment Share on other sites More sharing options...
Aphatspliff Posted January 1 Share Posted January 1 Just found this old thread, a variety of different answers I’m so confused now maybe I won’t go messing as my last run was the best one I’ve done 1 Link to comment Share on other sites More sharing options...
Aphatspliff Posted January 1 Share Posted January 1 (edited) Nice one dude. I think we wrote our last posts at the same time. I’ll stick to what has worked fine so far @GSZZ Sorry to take your thread of topic Trashedagain! Edited January 1 by Aphatspliff Threadjacker 1 Link to comment Share on other sites More sharing options...
MrSlatersParrot Posted January 1 Share Posted January 1 Just now, catweazle1 said: You would be adding chlorine in macro amounts when it's meant to be a trace nute. I ask because I used to work at a plant research unit where we made up our own plant nutrient. I'm no kind of chemist, we used a recipe which was a modified Hoagland solution and we used HCl as the pH down, I believe it's quite common in the science world precisely because chlorine isn't a major nutrient. We grew loads of different plants for researchers, never heard anyone have a problem with it. 2 Link to comment Share on other sites More sharing options...
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