Fan Leaves drying/dying in veg...what is it?

These are under a 150 watt mh, temp is 24C. The fan leaves are turning brown/yellow and drying up from the tip inward. Not just the ones at the bottom, even newer ones. I repotted these into 4 gallon pots a few weeks ago...no nutes, just garden center soil...maybe the problem.

I tried to diagnose it myself...symptoms look like phosphorous defficiency perhaps? I dont have much air circulation, could that cause this...the temps don't seem too high, or are they?

From the looks of it I'd say the lack of circulation is the problem. GardenSafe is a safe fungicide which I've used with success on similar looking plants (green spray bottle at home depot). Snip off the parts of the leaves which are dead then follow the directions on the bottle. In addition you need to be sure you have some good air movement, and try to check your relative humidity. My plants got that fungal growth a couple times before I realized was a humidity issue, and not a nute problem. I've found that an Rh of 70 is pushing it and now get along fine at 65 Rh.

Thanks for the input...I was thinking circulation could be it, but with the temps being relatively low (24C) I wasn't sure why the leaves would dry and curl up....humidity is really low as well. I put a fan in there, I'll be able to either confirm or rule out lack air circulation soon enough.

Jim Lahey said:

These are under a 150 watt mh, temp is 24C. The fan leaves are turning brown/yellow and drying up from the tip inward. Not just the ones at the bottom, even newer ones. I repotted these into 4 gallon pots a few weeks ago...no nutes, just garden center soil...maybe the problem.

I tried to diagnose it myself...symptoms look like phosphorous defficiency perhaps? I dont have much air circulation, could that cause this...the temps don't seem too high, or are they?

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Hi, How often are you watering? Is your soil staying wet? Let things dry a bit if the soil has been staying wet...Why no nutes? They're big enough, potting soils only have nutrition for about 3 to 4 weeks then you need to feed, and I'd start by using lower strength mixes on smaller plants.Good Luck

The garden soil will probably be holding too much moisture around the root area causing the plants to stress. Cannabis prefers fast draining lighter growing mediums than that type of soil.

Also you need to be changing the air in your grow room the same as air outside is always moving in and away from plants. Changing the air is not only an issue of controll temperatures, plants need to perspire moisture as well and have that moisture taken away from them or else humidity will get to high and plants will suffer because of it.