I've got this plant growing pretty well. I have read that low humidity is bad and will cause necrosis of the leaves and light burningof leaf tips. I have a constant 30% humidity and some of the lower leaves are doing as I described. I thought that is was fert burn so I cut that out and it's still there just slowed down. If the humidity is a problem can someone tell me a remedy. I have a closet setup, 3X4X7 area, 1000 Watt MH,80 cfm intake and exhaust fans. Temp stays right about 85 w/ 30% when the light is on, and about 65 with light off and 40%humidity. Im new to this so any info would be appreciated.
I have always wondered how to remedy this problem myself, since at this point in my life I'm limiting myself to low-budget closet grows with macguyever type solutions to problems. That 1000W MH is creating a lot of heat dude, and I'm assuming you have the output fan right next to it somewhere up at the top of the closet. If you have room for cups of water, put them around so that there will be more air/water surfaces created in your closet, and with that type of heat, the air can carry a lot more moisture. If you don't have room for cups, I was thinking...although I've never tried this, putting spounges on top of your soil soaked in water so that they evaporate slowly into the air... The only thing I'm worried about is that the intake/exhaust air system in your closet is powerful enough to take the -apparently- very dry air outside into your closet faster than any water can evaporate and accumulate, thereby limiting the relative humidity.
will a humidity of 20% and lower cause new growth to stunt? since i moved my plant into a small closet for flowering the new growth has totally stopped.
Humidity issues usually show themselves in a physical way, rather than a stoppage of growth... Stress to your plant can always stunt growth, and thats why taking care of plants is what I consider a pretty full-time job... During flowering, humidity should be way lower than during vegetative anyways, but I would think that your leaves edges would slight curl up if they were dry, and you could feel the lack of moisture in the leaves... Those look like some skinny ass sativa leaves you have on those, and as far as I know, sativa's are picky and difficult to grow if you don't have the right environment, since they originate from tropical regions, where temperature and humidity are high (and growing seasons are long).
Plants take in moisture through their roots not their leaves. The only exception to this would be rooting clones. Those take in moisture through the leaves because they have no roots, which is why they need to be sprayed twice daily. In the sick plants journals there is no real write up on humidity problems. The only problem where humidity comes into play would be mold and the spores would have to be present anyway otherwise no mold even if the humidity is unusually high. With that said I doubt you have a problem due to too low humidity. The optimal range however is 40%-60%. If it bothers you that it is so low, add a bucket of water or a wet towel to the closet or buy a humidifier. By the way, you have a full sativa there so that's why the thin leaves.