Hi all- This is my first post in the forums and I apologize in advance if the thread is not in the correct spot. I need some advice from some growers that are more experienced with rdwc than I. \nLook at my leaves- curling/ drooping/ discoloration. Enough said \nHere is my set up •8x8 tent •(2) 1000 watt MH Lights •indoor temps 78-80 •Res Temp 65 •General Hydroponic Nutrients- Flora Series- •Running a RDWC system •18/6 light cycle •PH was 6.5 ( i know it was high) today i lowered to 6.0 (prob should be 5.8) •PPM's mid 500's \n*Water level was about a 1/2" -1" below net pots- I just today lowered the level to about 2-3" below net pots. \n**These rooted clones were put into this environment 4/27- according to the General Hydroponics feeding chart for expert rdwc- I am due to up my nute level as of 5/4 ( week 2) . I purposely did not adjust any feeding schedule yet because they looked like they were doing so poorly \n**I was topfeeding for first week- I just stopped topfeeding about 2 days ago when I saw the majority of the plants had a couple of 3-4" roots poking out of the netpot. I still have 2 out of 15 that have not poked through yet but I can tell it will be any day. All others now have multiple strands of roots that are anywhere from 3"-9" long id say. Thanks in advance to all! Glad to be part of the forum
Your right, so lower the ph to 5.8 because your locking out P and K, with Ca and Mn are slipping in nutrient uptake. Zn is also locked out. http://hydro-heaven.com/yahoo_site_admin/assets/images/ph_Chart_3.208114926_std.gif
Thanks OC. its at consistent 5.8 now- I like the lockout chart too Could this issue be becuase I am ready for week 2 feeding scheule which inclues stronger nutes? I purposly have not flushed and increased nutes becuase the plants did not look happy. They are on day 11 of the week 1 scheudle- in other words, they were due for the flush and adjustment of feeding scheule about 4 days ago... **I would think if they needed more / or stonger nutes my PPMS right now would be much lower- they are mid 500's right now??
it looks like over fert and oxygen starved roots to me. The pH getting up to 6.5 isn't the major issue IMO.
I didn't say 'NOT an issue' (but yet, you put it in all caps like I did say it). What I said was 'it isn't the major issue IMO' As in; I don't believe that the pH is the major cause of the stress I see in those pictures (IMO), just a small part. IMO -> In My Opinion. I'm sorry if it offends you that my opinion differs from yours. I've only been growing hydroponics for a little over 20 years. What do I know.
Wasn't offended, not in the least because over fertilization always lead to a skewed ph. Hydro always dictates a balance, Op will need to learn that. I apologize for the misunderstanding on my part. You have a great day.
The issue is nothing to do with pH. It's a lack of oxygen, and the ppm is a little high, I certainly wouldn't raise that at all. what air pumps are you using? They look like they have taken a while to settle in to the clay balls, this is often due to net pots being too big and slowing oxygen transportation around the roots or rockwool for the same reason. Now that roots are leaving the clay balls growth should take off. You may need to add more air though. Definitely don't raise the nutrient strength. I would have them at about 300- 350ppm
Here's a good read for you. http://www.just4growers.com/stream/hydroponic-growing-techniques/airing-out-the-truth-on-dissolved-oxygen-in-hydroponics.aspx
Good link. I particularly liked this part. --------------------------------------------------------------------------------------------------------------------------------------------------------- Hydrogen Peroxide Adding hydrogen peroxide is a common practice used by many hydroponic growers but is one that is seriously misunderstood. There are 2 forms of oxygen: O[SUB]2,[/SUB] the diatomic form which can be absorbed by the plant roots, and O[SUB]2[/SUB]-, the free radical form which is highly reactive. Hydrogen peroxide (H2O[SUB]2[/SUB]) converts to H2O + O[SUB]2-[/SUB] when added to water. The O[SUB]2[/SUB]- that is formed is not desirable because it will indiscriminately oxidize or damage healthy living plant cells. Also, although adding hydrogen peroxide to a reservoir will result in an initial boost in DO levels, those gains are short lived. Hydrogen peroxide is best kept in a grower's toolbox for cleaning equipment and treating bacterial and fungal infections. --------------------------------------------------------------------------------------------------------------------------------------------------------- It always amazes me the number of people who profess using H2O2 as a regular part of their regimen. Any time I have tried to offer the notion that H2O2 is not a good thing to use as a regular part of a nutrient regimen, someone gets offended and acts like I just kicked their puppy.
I understand what you're saying ... I've also seen folks place CO2 in their tent or room with their air-pump and create issues with ph.
Hmm, that's a good point. I never thought about that. Pumping CO2 into water through an air stone would definitely carbonate the water to some extent (a small amount), and carbonated water is acidic (carbonic acid). I don't know how high the PPM level of the CO2 would need to be, but if it's released anywhere near the air pump intake, I could definitely see some carbonation happening.
Copied: The correct way to notate the dissolving of carbon dioxide into water is: CO2(g) + 2H2O(l) <-->> H3O(+) + HCO3(-). Since carbonic acid is (defined as) a weak acid, the amount of the acid, H3O(+) is low, slightly increasing pH. HCO3(-), the strong conjugate base, drives the water <--> acid/base equation, H2O(l) <<--> H3O(+) + HO(-), to the left. greatly decreasing pH (actually, it greatly increases pOH). The small amount of H3O(+) is greatly countered by the large amount of OH(-), and that decreases pH. NOTE: The (g) and (l) stand for gas and liquid. The (+) notates the hydrogen ion (acid) and the (-) notates the conjugate hydrocarbon base ion. The symbol <-->> means the equation is reversible, with more products formed on the right side of the equation than on the left side. Source(s): Environmental Geochemistry class
Thanks for all the replies! I think they look a bit better from adjusting the PH As far as my air pump I have a Elemental 950 gph air pump that I split into 16 ports. Air lines from pump to buckets are not all the same lenth which could have something to do with the problem, but I am going to get another pump asap and have each pump split into 8 ports. Also I have heard from people that I need to up my ferts because they are not seedlings anmore so I have them underfed and some poeple say that I should not increase change or flush nutrients. I was going to flush and get them on the week 2 feeding scheudle ( see origional pics) tomorrow. Should I wait until I get another airpump and let them recover a bit? Thanks guys!!
I was wondering if you'll be using a CalMag product? Cal-Mag plus is an excellent product, especially if you're using RO water. It's formulated with nitrates that are anions that can push a ph higher if formulated with phosphates, sulfates, carbonates, and bicarbonates. This product is formulated of course, with Mg. and Ca., and chelated Fe which are anions that can push the ph lower. A good "balance" of nutrients are applied but the ingredients are labeled as calcium nitrates, magnesium nitrates, and iron EDTA (chelated). Could be a bit confusing for some folks until they understand that balance in hydro and the difference in ingredients in hydro that effect ph.
No I have not been using cal mag, but I sure am thinking about getting some now, however I am not using RO, just a small boy 2 stage with kdf85 filter.