Big issues - might lose plant... (maybe too late?)

I was originally posting about this in my grow journal thread but it’s quickly spiraling out of control. This may be more than a single issue (and probably is).

So, everything was fine. I went from a meh light (vipar 400) to a really good light (HLG 600H). This bumped the temperature up from 70~73 to 79~81 during lights on (it sits around 68~70 lights off). I’ve always been struggling with humidity, or a rather a lack thereof, usually varying between 28~34%. The leaves started drooping a few days ago. The soil was dryish, so I watered it lightly. They continued to droop. It took 3 days for the water to be used. I posted in my grow thread and it was suspected that the humidity was the issue (and since at the time it had reached an all-time low of 24%, this seemed reasonable). I managed to get the humidity up to 38% but was unable to keep it there, it then dropped and stayed at 35% through last night.

Today I went and purchased a new humidifier and I’ve gotten the humidity over 50%. It’s only been a few hours, however, the lights just came back on and the plant is significantly worse off than yesterday leading me to make this thread dedicated to this issue.

Pictures follow. Taken under the white light of the HGL 600H (3000K).

The leaves are still drooping and the pot is light, the soil is moist but not wet.

What size pot? It looks maybe root bound or overwatered.

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@MattyBear 5gal, however it has sunk in a bit. It was wilting like that when the soil was just moist, not wet, container was light. I thought maybe it was under watered so I gave it some water, just enough to feel a difference in the weight of the container, and it did not improve. Not only that but it took a long time to use the water I gave it even though it wasn’t very much.

I may have figured it out, tell me if this could cause it. I got my containers mixed up, just realized I gave it unmodified distilled water by mistake, pH ~5.8 (assuming the meter is correct)

I had the same looking problem last week @dbrn32 my problem was underwatered, bigger the plant hotter the light more fluid needed. I gave mine enough to runoff into the runoff dish and eveything came back to normal,
can you adjust the wattage on the HGL 600h ? but if your PH is out that wont help either, but i say again lack of water was my issue, they drink it like an Aussie with free beer :kangaroo:

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when I gave it water it took forever to use it, but the water I gave it was the wrong pH, I guess I’ll try water of the correct pH, I’ll adjust it to lean higher rather than lower (~6.8?) hopefully can bring it up a bit. Usually the water I use is around 6.3~6.5 so it was already on the low side, that 5.8 water probably brought it way down.

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What does the runoff water measure? @blackthumbbetty

You need to keep your humidity up. Your plant will not be able to drink properly if the rH of its environment is too low, or too high.

Have you read about Vapor Pressure Deficit? It’s how temps & humidity work together to ensure your plant can beathe, eat, and drink properly.

If your temps are high & your rh is low, your plant tries to conserve moisture by keeping its stomata closed (think of them like tiny mouths on the leaves). With the stomata closed, the plant cannot move fluids from the root zone to the leaves, so the plant might start showing signs of distress. That’s why it seems like your plant isn’t drinking a lot: it cannot drink properly.

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I think @raustin gave him a Humidity table on his grow journal.

@Hungrybud @raustin Just watered it. I put a gallon of pH 6.98 into it, barely any runoff, collected maybe half a cup, pH 5.58. Water was brown.

This assumes the meter is accurate, chemical-based tester coming tomorrow so I can confirm if it is or not. I did run through the calibration. It measures distilled at 5.8 and bottled at 6.2 (which the brand has an average of 6.2 according to a Google search) so it seems accurate.

@blackthumbbetty I did not know about this prior to @raustin posting it in my grow journal. I’ve since corrected the humidity, it was over 40% just now when I watered it.

Would his extractor system take any of the humidity away @blackthumbbetty i am only still learning @rampage i have no extractor or filter i just use circulating fans atm, my humidity is always around 60 to over 70% but i am in Australia

It’s a ph issue. The humidity soundn’t really be that much of a problem. Looks like phosphorus and magnesium deficiencies. A flush may be in order to correct the ph.
What kind of soil are you planted in?

Also under watering could cause the leave to look dried out. Make sure to water to run off.

@shindig153 It’s Miracle-Gro Nature’s Care (“with water conserve”), amended with ~30% perlite.

Hey bud , I have same problem with low Rh, with all my efforts I figured out largebuckets of water with cloths in them as caused my Rh to go through the roof, easy to lower it now :+1:

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Miracle grow could be the problem. It’s not designed to grow marijuana. If it were me I’d consider repotting in an organic soil. The slow release nutes in miracle grow isn’t easily flushed away and more than likely you will chase this problem all the way through the grow.

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Trying to measure ph of distilled is difficult, but it shouldn’t be 5.8. I would take a look at calibration of your ph pen while you’re at it. If you get enough things out of whack problems can be difficult to diagnose. If you don’t have good plant respiration even a small amount of water in pot can make plant appear over watered. It basically is since the plant isn’t drawing in water the roots just sit there in soggy medium. 81 lights on and 70ish lights off should be about perfect with your light. Get the humidity up and double check your ph pen is reading properly or calibrate it. I suspect things will start looking a little better for you.

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It’s definitely a balance. Need enough exhaust to keep the air in your grow space healthy for your plants, but not so much that it sucks out all the humidity.

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I flushed the plant with about 8 gallons of water, started consistently reading 6.0 so I finished with a gallon of nutrients (fox farm week 4 schedule, half strength). Hopefully with the humidity under control this resolves everything. Guess we will see…

@dbrn32 I thought that too, but I googled it and apparently 5.8 is just fully CO2 saturated distilled water. It was off brand distilled so not super surprising. It reads the buffer solutions fine, of course they were made with that same distilled water. I’ll know more tomorrow since I have a chemical based tester coming. In the mean time it’s my only means of measuring.

I’ll check back in a few hours or days, depending on how long it takes to get better or worse.

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