Low humidity problems? black/goldish spotted curled leafs(pics)

Hello everyone, first time on the forums and also a first time grower. Right now I am growing in a 5x5 and 4x4 grow tents using DWC. I am having problems right from the get go, going to lay out what has happened so far, hopefully someone can help me out.

I have had problems with temperatures, root rot, humidity. I believe I fixed all the problems pretty quick, I adjusted the air flow in my room which helped with temperatures(70-79 range now, but usually stays around 73-75). My water temps are 70/71 degrees, so I kind of guessed I was going to get root rot. I caught it right from the get go and applied hydro guard, now the roots are 100% white and healthy. Now, the humidity is just HORRIBLE. I live in a very dry area. My humidity for a while was around 16%, I have been trying to fix it, not to much luck though. I have added a humidifier, open bucket with air stone, and tray with water with a fan blowing over it(pics below). It raises the humidity to 31%. I sprayed down the walls with RO water, that raises it to 55%, but it only hangs around 55% for 20-30 minutes and then slowly goes back down. So any other recommendations to help raise humidity would be greatly appreciated, cause its just way to dry. I believe that is what is causing the blackish/goldish spots on the leafs. Not for sure though, It seems there is some nutrient deficiencies and maybe nutrient burns as well? PH was around 5.9/6.0, after sitting for a few days it went up to 6.3 in the buckets, maybe lower PH in the buckets?

Just some information on the plants, nutrients and what I use.

Plants around 2 weeks old, maybe a little younger. I use flora trio at 1/4 strength. water is RO water. I use an air cooled hoods, lights are about 20 inches away from plants.

Any ideas what this is?

I also grow using RDWC and GH trio. I have seen this type of distress on my plants before and it's usually caused by a Ca deficiency. I would consider upping your nute concentration-especially the Flora Micro.

Curled up edges looks like low rh- bring up to 65%. You can try a small cheap humidifier, or even just a few buckets of water with towels/rags patially submerged and draped over edge to wick up and help evap more water.. careful not to wick all water out onto the surrounding floor though!! a lot of work, but just an idea

High yourlook

I have the same problem with RH. Excess transpiration by the plants causes excess nutrient uptake which leads to toxic salts buildup and fried leaves. As long as your exhaust has to keep coming on it's damn near impossible to keep the RH up using any of the above stated methods.

Need to feed humidified air directly into your intake so as moisture is being pushed out fresh moist air is coming in. A humidifier that can do that is going to cost a bundle. I'm opting to run lower ppm nutes to compensate and it worked pretty good my last grow.

Same kind of thing happens using CO2 unless you have a sealed room. When the exhaust turns on the CO2 is lost then has to inject more in to get it back up. Right now I have my room temp balanced so the exhaust doesn't kick in, the RH stays up around 60% and I have a DIY alcohol lamp in there to keep the CO2 up. Working pretty good. I have a CO2 controller that shows me the level so I know it's working.

A trick I use since I'm too cheap to buy another humidifier is wet rags hanging on my support bars at the top of the tent. A little bit of a pain wetting them a few times a day. But it's a great way to get your RH up in a hurry.

OldMedUser said:

High yourlook

I have the same problem with RH. Excess transpiration by the plants causes excess nutrient uptake which leads to toxic salts buildup and fried leaves. As long as your exhaust has to keep coming on it's damn near impossible to keep the RH up using any of the above stated methods.

Need to feed humidified air directly into your intake so as moisture is being pushed out fresh moist air is coming in. A humidifier that can do that is going to cost a bundle. I'm opting to run lower ppm nutes to compensate and it worked pretty good my last grow.

Same kind of thing happens using CO2 unless you have a sealed room. When the exhaust turns on the CO2 is lost then has to inject more in to get it back up. Right now I have my room temp balanced so the exhaust doesn't kick in, the RH stays up around 60% and I have a DIY alcohol lamp in there to keep the CO2 up. Working pretty good. I have a CO2 controller that shows me the level so I know it's working.

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What the heck is an alcohol lamp? Are you referring to a lantern burning alcohol?

ColoradoHighGrower said:

What the heck is an alcohol lamp? Are you referring to a lantern burning alcohol?

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Yep. Methyl hydrate, aka wood alcohol, aka methanol. About 200-300ml/day is lots.



When burning in the grow room.



Made a single wick one for the veg plants in the bedroom.

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Thanks everybody for the replies! Very helpful.

@GBAUTO, I changed out all my reservoirs and upped the nute concentration. Will update on how they are doing, thanks for the info.

@ColoradoHighGrower, yea I know. Trying my best to raise the humidity levels. Right now I got the humidity levels steadily around 40%. I already put a humidifier in there(there's a picture of it up above). I put an extra tray in there filled with water with a fan blowing over it. Plan on trying your towel idea though, thanks.

@OldMedUser, I tried to put the humidifier where the intake air is coming in. It never worked. But I do see what you are saying, I think the room the tents are in just isn't sealed up enough to where I can raise the humidity. I am upgrading to a full dedicated grow room next year, so hopefully that solves my current problems. Plus tents are pretty hard to move around in. Thanks for the info.

@InigoMontoya, I plan on trying that today, hear a lot of people recommending that, I am always down for extra work if it helps my babies in the tent out.

Again, thank you all for your help. I would like your comments, just don't know how to yet. And hopefully I am tagging people correctly.

OldMedUser said:

Yep. Methyl hydrate, aka wood alcohol, aka methanol. About 200-300ml/day is lots.

View attachment 4069114

When burning in the grow room.

View attachment 4069115

Made a single wick one for the veg plants in the bedroom.

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Dude. That is some MacGyver shit right there! Way to go!! A little sketch having open flames like that, but looks like you have it pretty well contained. Do those copper pipes heat up at all? You should be really care how and when you light/extinguish/handle those to, mostly to avoid spills near the flame!

ColoradoHighGrower said:

Dude. That is some MacGyver shit right there! Way to go!! A little sketch having open flames like that, but looks like you have it pretty well contained. Do those copper pipes heat up at all? You should be really care how and when you light/extinguish/handle those to, mostly to avoid spills near the flame!

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The top doesn't get hot enough that I can't touch it if it runs for hours. We had exactly the same kind of burners in grade 8 science labs and as I was a chemist in a hazardous waste facility in charge of the flammables section I'm eminently qualified to operate that little unit.

Only takes about half an hour to get the CO2 levels over 1500ppm and as the exhaust fan doesn't come on at all it will stay above 1000 for about 2 hours. The plants keep the RH up nicely so it's running good down there now. I found some wire nuts that fit snugly on top to prevent evaporation when not in use and it blows out easily or just put the nuts on to snuff the flames.

No chance of spilling it and if it runs dry I flip it over after refilling so the wicks get wet quicker and not a drop spills out.

If its not rh could it be they are just a little hot from the lights?

I hung some wet/damp towels inside the tent. That brought the humidity levels steadily around 51%. It was at 61% for a while. Thanks for all your help.

But I do have another question, I changed out the reservoirs because I believe my PH was to high(around 6.3). The fresh nute mix that I just put in there had a PH of 5.8 before I put it inside the tent, I checked the PH again today and it was at 6.3/6.4. Is it normal for it to rise that high? I am thinking about dropping just a tiny bit of PH down to get it back down to around 5.8 which from what I have read is the sweet spot when growing in hydro.

Its ok for ph to drift in the 5.8 to 6.3 range

As different nutrients are aborbed at different rates for different ph ranges .

Not too much to worry about if your doing res changes.

If your maintaining a res for longer then a week then you would ph down AFTER you let it drift to 6.3

Then after youve topped up with enough water to equal the res you should swap for a fresh batch

Thanks for the reply, glad to hear that its okay/normal. I plan on changing the reservoir every 7 days, so next time I will expect this.

One of the best investments is an industrial humidifier... I like the nutramist as you can pipe and t it as directional fog.

Low humidity can be temporarily remedied with a foliar feed.
A fine mist of RO and a surfactant as often as you like can replicate a humid enviorment.

This really helps to keep plants from getting tissue damage while you're finding a long term fix.

2 things about this though.

1) if you add nutrients to the foliar feed especially synthetic, you could both clog the pores with big molecules like calcium and nutrient burn pretty easily as well as disturb the little known microbial life that live on the leaves themselves.

2) Foliar feeding reduces transpiration in turn reducing the water uptake. Reduced water uptake leads to stagnant water with little to no dissolved oxygen. Root rot and the overwatering "claw"
Feeding during the warm part of the light cycle helps evaporate water in the soil enough to introduce oxygen in the rootzone during periods of low transpiration.

@yourlook @pinner420 totally agree- towels are the quick and cheap short-term remedy, but really short-term! My 3gal humidifier with auto humidistat has been life changing, and you can get decent units for under $100 USD.... Personally, i think it's well worth the investment.

OldMedUser said:

The top doesn't get hot enough that I can't touch it if it runs for hours. We had exactly the same kind of burners in grade 8 science labs and as I was a chemist in a hazardous waste facility in charge of the flammables section I'm eminently qualified to operate that little unit.

Only takes about half an hour to get the CO2 levels over 1500ppm and as the exhaust fan doesn't come on at all it will stay above 1000 for about 2 hours. The plants keep the RH up nicely so it's running good down there now. I found some wire nuts that fit snugly on top to prevent evaporation when not in use and it blows out easily or just put the nuts on to snuff the flames.

No chance of spilling it and if it runs dry I flip it over after refilling so the wicks get wet quicker and not a drop spills out.

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Nice! Sounds like you're basically OSHA approved! Lol What's an approximate ideal co2 curve throughout a typical grow? And what is normal concentration (at sea level or 5280?)

ColoradoHighGrower said:

Nice! Sounds like you're basically OSHA approved! Lol What's an approximate ideal co2 curve throughout a typical grow? And what is normal concentration (at sea level or 5280?)

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I don't figure curves into it. Just get the ppms up and figure that helps enough. 400ppm is normal sea level now with about a 3% drop for every thousand feet up. My controller has adjustments for that but I don't bother and I'm just using it to monitor the CO2 levels so don't need to set that. We're only at 1500' here. Might be even better for you at that altitude.

I figure anything over ambient and enough to make sure the plants don't run out is good enough. Only during the stretch do I really want 1500+ to support the growth spurt. Then I let the heat get up to 90f and add extra light and feed.

Just giving another update, everything is looking good and plants are already starting to look much healthier.

@pinner420 Funny you say that, was literally looking into nutramist. Seems to work great and puts out a lot of fog to raise the humidity levels. Plan on getting one here soon.

@ColoradoHighGrower Right now I have a 1.5 gallon humidifier in there. Might upgrade to 3 gallon if it performs better than a 1.5 gal. I have to refill it only once or twice a day.

All the plants look extremely healthy and the roots look even healthier. Nothing but straight up white. Stems are thick as hell. Glad I didn't add PH down when the PH levels rose to 6.3 in the reservoir, it eventually went down to 6.0(currently), so shout out to @Cold$moke for saving my ass. The only one that is acting a little weird is the one in the back left corner. Providing some pictures right now. The PH in that reservoir is 6.0 and the roots are white as can be. So don't know whats wrong with it. I raised the light a little bit and turned off the big fan as I think it was providing a little bit to much of a breeze through there, so just leaving the little fans on for now. Temp is floating around 77 right now with a humidity level of 55%(rises to 65% for about 4/5 hours when I put a fresh damp towel in there).

Plants in the 4x4 are looking good, just a little slow growing going on compared to the plants in the 5x5. Hopefully they catch up. Anyways, here are the pics of the one having problems in the back left corner in the 5x5.