HELP! Yellowing, and curling plants.

[WiredKydd]

Im new to growing and i just found your site 2 weeks ago, I had noticed my plants starting to yellow on the bottom growth and it was slowing rising to the top. This looked like classic Nitrogen deficiency but 2 weeks into a correction of some Nitrogen booster 1-0-0 added to my watering and the symptoms have not gotten any better. I thought it might have been wind burn so i moved my fans around as well (2 weeks ago) no luck. I have been checking the temps but dont think the heat is to much as all my plants show a little bit of this stress and i keep it around 73 in the tent with an RH of 25-35%.

Cycle: 3 weeks into Flower

My setup: 5x5x7 tent, 1000w HPS (Set to 750w), 7g cloth Pots, 3" risers, 16" saucers, Gen Hydro Nutes +Calmag, 2 12" fans, 445 CMF inline fan. Tent is kept at 70-75 Fahrenheit and RH 25-35%, Water comes from RO system and is always Ph'd to 6-7.

[Daskahn]

Do you have a jewelers loop they might be done... but if I was you I’d flush with plan PhD water

[WiredKydd]

Do you have a jewelers loop they might be done... but if I was you I’d flush with plan PhD water

My water is always around 6.2-6.7 and it comes from my RO system. the plants are 3 weeks into flower.

sorry both of those details should have been in my post.

[Damngrower]

Might be worth checking for Wpm, if you've got something you use for pests that is safe then give that a go. If they respond it should help narrow down possible problems.

[WiredKydd]

Might be worth checking for Wpm, if you've got something you use for pests that is safe then give that a go. If they respond it should help narrow down possible problems.

im not sure what WPM is. i did end up with white powder mold at one point and used, water, baking soda, little bit of soap (1-2 drops) to spray over my plants. it seemed to kill the mold pretty quickly.

[Damngrower]

Yep that's the stuff. I'd suggest giving them another spray, it won't hurt them and if they start to recover you'll know you're on the right track. It can be a bitch to get rid of, cost me about half an ounce of harvest once. I use neem oil, it works a treat, but I wouldn't use it once flowers start to appear.

[WiredKydd]

Yep that's the stuff. I'd suggest giving them another spray, it won't hurt them and if they start to recover you'll know you're on the right track. It can be a bitch to get rid of, cost me about half an ounce of harvest once. I use neem oil, it works a treat, but I wouldn't use it once flowers start to appear.

so youre thinking its probably still mold? I had a friend tell me to use hydrogen peroxide, ideas?

[Daskahn]

I’ve used small amounts of hydrogen peroxide to treat root rot few grows back worked great.. but reason I asked about the jewelers loop is because some strains leaves yellow like that when they are done..

[Rwise]

Another home remedy for WPM is 1 part milk to 8 parts water.
I used Trifecta Crop Control safe up to harvest but costly
Also they need air movement as in fans and I thinned out the under growth as well, nothing should touch another

[Damngrower]

It could be, at that stage in flower it can sort of hide in the trichromes and be harder to spot. I don't know much about hydrogen peroxide but it doesn't sound like something I'd want on stuff I was gonna smoke. What you did before or Rwise's suggestion would be the safest stuff to try I reckon.

[WiredKydd]

Thanks guys, ill have to grab a shot when the lights go out (with out the HPS blinding) to show updates. I saw new growth today and was thinking maybe its the old growth dyeing off as it cant regenerate.

[dilvish]

Looks more like heat and light stress. In one or more of those pics you have leaves at the top of the plant that look as though they are burnt. Canoeing or tacoing is a sign of heat/light light stress combined with potential underwatering. Considering the humidity is quite low in your tent. How often do you water?

Although you stated your heat was around 75F (is it accurate?) the lack of humidity and distance from the lights could be your problem. I don't think I've ever let my Humidity go below 40 even in the flowering stage.

I'm unsure as to why WPM would even come up considering the humidity level...if you are treating it for WPM and it isn't suffering from that then you may be causing more damage than good.

Try just flushing with plain PH'd water for the next 2 waterings, up the humidity a little and move the lights up a bit (4 inches). Just make sure you are not over or under watering. let them try to adjust over the next week or so.

Also good to remember is that fans only move the air around they do not dissipate heat. fans allow airflow, reduce the likelihood of hotspots and deter some pests, like spidermites.

[WiredKydd]

Looks more like heat and light stress. In one or more of those pics you have leaves at the top of the plant that look as though they are burnt. Canoeing or tacoing is a sign of heat/light light stress combined with potential underwatering. Considering the humidity is quite low in your tent. How often do you water?

Although you stated your heat was around 75F (is it accurate?) the lack of humidity and distance from the lights could be your problem. I don't think I've ever let my Humidity go below 40 even in the flowering stage.

I'm unsure as to why WPM would even come up considering the humidity level...if you are treating it for WPM and it isn't suffering from that then you may be causing more damage than good.

Try just flushing with plain PH'd water for the next 2 waterings, up the humidity a little and move the lights up a bit (4 inches). Just make sure you are not over or under watering. let them try to adjust over the next week or so.

Also good to remember is that fans only move the air around they do not dissipate heat. fans allow airflow, reduce the likelihood of hotspots and deter some pests, like spidermites.

I water every 3 to 4 days. As soon as i see the plants start to look thirsty they get water. Every other watering is a feeding with GenHydro's Big 3 + CalMag.
I can up the Rh of my tent to around 35% fairly easy. My light can be moved up about 4" max so ill do that tonight before the light comes on. I may even bend that tall girl down a bit and pluck all the damaged leafs.

[dilvish]

when do the plants look thirsty to you? You don't think dry brown and yellow leaves curling upward is a sign of lack of water? It is THE biggest sign!!! Your plant looks majorly stressed likely from the air being too dry and potentially not enough water. If they aren't getting at least 1 gallon or more each (you said they were in 7g pots) they are dehydrated, especially considering the humidty levels. Additionally HPS lights tend to put out more heat than say LED so when you test the temp in the grow space make sure you do it around 3+ hours after the lights switch on and test the temp every couple of hours to be sure. As it warms up outside so too does the grow space. That can have an affect. Like my grow room...when the lights come on at 5AM in the morning its around 23C. by 9AM when my fans kick in, it is 26C. By 5PM the room temp is at 28C and stays there until 11PM when the lights and fans shut off.

[Damngrower]

Ah yeah, hands up, I didn't see your RH numbers! *facepalm*

[WiredKydd]

im going to increase the Rh to around 35%. The plants start to droop a little when they show they need water. They are in 7g pots and i water them 2 times a week with 1g each. First water is nutes (1 gallon), second is just water (1 gallon) i have recently added a little nitrogen into the water cycle as they definitely had a nitro deficiency

[Damngrower]

Do you get any run off when you water them?