New Grower Help -- Heat Stress?

[bigfun]

Hello, my little auto -jack herer is showing some kind of stress on the leaves. Just after sprouting, temps went to 105F a couple of nights, so I thought it was just heat stress. However, it appears the new growth also shows these same symptoms, which is slight discoloration as pictured.. She is 17 days old, part of my very first grow, and seems a little small. It was started in Pro Choice Organic MG soil. Is this just how the plant will keep growing? Any tips would be greatly appreciated!

 

[Waira]

.... yeah, there's some heat stress signs, maybe more, or because of,... that yellowing in the newest growth, from center out, looks a lot like Fe defc., but a plant this young shouldn't be hit by it so soon,... this is a Miracle Grow soil? Often as not, we see prob's with their stuff,.. either to hot because of pre-charged nutrients, or off pH,... auto's tend to be rather nute' sensitive especially as seedlings,... the temps can mess with nutrient absorption, more so combined with low RH, strong breezes, putting the plant in a wtaer stress situation,... your temps were certainly hot enough, what was the RH? Did the soil get dry as well? ...under this stress, they plant closes up the stomata, to prevent too much water loss,...this shuts down the movement of nutrients as well, causing symptoms like this even if there's nutrients in there.... get us a pH and RH reading, meantime, get her cooler, and more even level moisture,....

 

[bigfun]

Thanks Waira ... from what I've read, you don't have to really worry about ph in a soil grow and I haven't a ph meter yet. The MG soil is the first I bought, but it's very low nutes. I've since obtained Happy Frog, and Coco Loco Potting Mix -- which I can transplant if that would help in the long run, but I've also read that transplanting is hard on autos. The relative humidity is between 35-51% ... temps last couple of days were 75-91F ... today it hit 99F, which I know is too high, but I have a fan coming, and still trying to regulate things. I gave her a good watering yesterday.

I have three other photoperiod plants that are 4 days younger in the same tent, and they are thriving with no signs of stress, and are all now bigger than my auto here.

Thanks again!