Running 4 plants in a rdwc using the lucas formula with AN jungle juice. The plants vegged at 850 ppm @ .5 conversion for the last 3 weeks of veg. Once I flipped the switch, my readings skyrocketed to 950 over night. No visible damage what so eveer. So to be safe, I drained and refilled the rez, cutting back to 750 ppm. Now the rez has stayed pegged at 5.6 ph and 750 ppm for the last 4 days. I am having trouble understanding how a plant can veg at 850 for 3 weeks with no fluctuation in readings, yet once switched to flower, major spike in tds. This seems backwards to me. My meters are all calibrated and everything else is going good. I am wanting to start pushing these plants, yet I am afraid to burn them. I have been going off my tds readings this entire run, and just when I thought I had it dialed in, here comes the curveball. Any ideas as to what may cause this? Also, is it wise to go ahead and start upping the ppm and see how they fare? They are currently on day 13 after the flip, and just threw the first few pistils 2 days ago.
I never had a spike like that in the PPMs, but then again I never had consistent numbers either. My PPMs would slowly drop over the course of a week or so until I fed them more, and the PH would slowly creep up in that timeframe. I don't know why your #s went up - aside from the obvious, that they were taking in more water than food - but now that you're in week 3 of 12/12 I'd start pushing them back up over 850, Take it slow and see what they can handle. BTW, I wouldn't consider a rise of 100 a 'major spike' or 'skyrocketing'. I'd have fluctuations of 50 PPMs in a day fairly often.
Right on. Well I was thinkin that kinda fluctuation wasnt good seein as how they have been within 10 ppm the whole grow. They went up to 850 last night. Thanks for the reply bro
give them the same as what they are using mate. if you give them more nutes than they require you will just slow growth. there's no such thing as "pushing", it doesn't work like that. test your solution and note the reading, then test again 24 hours later. if the reading has gone up your solution is too strong. if it has dropped it is too weak. if its the same or not moved much you have it correct
Well my readings never went up, they pretty much stayed pegged. However, I still went ahead and took them up to850 and everything looked great. They now are up to 950 and loving the shit out of it. No matter where I put my tds with these plants, my readings havent changed. No burns, just happy ass plants throwing flowers like mad!!!!!!!
I am really just interested in what would have caused that reading to go up so much after flipping the switch
if it has gone up it means the plant is using a lower ratio of water/solids so what is left behind gets stronger and stronger until it pulls water from the plant via osmosis. this is where the plant will start to show signs of ill health but the damage is already done. keep the strength the same as what the plant is currently using for maximum growth. giving them a stronger solution will not make them use up nutes faster, it will slow it down
when you say "flipped the switch" do you mean changed from, for example metal halide to HPS? If so, youre using a MUCH brighter bulb which creates more heat/lumens making the plant use more water which raises TDS because it makes the solution richer. So what did you switch from to?
Hey man! When your plants start to flower, the surface area of the plant increases dramatically, while it's overall volume appears to only change minimally. This will cause it to draw up much more water than it did in veg. If you keep topping up with fresh water, your nutrient level and pH should even out a bit. It's perfectly fine and normal to have fluctuations in pH and TDS. You must react appropriately by doing the right thing as often as necessary to keep these within the proper range. Be sure to top off with fresh water first, then adjust with pH up/down afterwards.
solid advice but his issue seems to be happening much too quickly to be "surface area" of the plants as it started overnight
Plants have been given another rez change and upped the ppm to 1020. They have been between 1020 and 1050 the last 3 days. Look great and pumping out flowers like crazy. I am hoping that it was some freak thing, or perhaps my water level had dropped more than I thought causing that spike. Either way, they are loving the shit out of the higher ppms as far as I can tell. If it was too much I am sure I would see evidence of that by now, wouldnt I?
Yeah, you would definitely notice if they couldn't handle 1000 PPM. But that's in the normal PPM range as long as you have a good intense light on them (400 watt HID or above). Glad things are going well.
for the best growth rates keep the nute solution balanced with the plant. if its imbalanced to the point that the plant is showing signs of ill health you will have a lot of making up to do if your EC level rises, your nutrient strength is too high if your EC level drops, your nutrient strength is too low if your EC levels remains stable, you have it correct
[quote name="GoldGrower" post="18315093" timestamp="1373201293"]for the best growth rates keep the nute solution balanced with the plant. if its imbalanced to the point that the plant is showing signs of ill health you will have a lot of making up to do if your EC level rises, your nutrient strength is too high if your EC level drops, your nutrient strength is too low if your EC levels remains stable, you have it correct[/quote I realize this as this is how I have been growing. My question was hoe they could remain at a certain ppm range for weeks, then jump like crazy overnight. Sent from my HTCONE using Grasscity Forum mobile app
When you say you flipped the switch, did you use the same type of light? Or did they go from veg under fluorescent and flower under an HPS? This increase in heat could cause more transpiration, leaving a nutrient solution with a higher EC than originally.
