Losing fan leaves after 14 days - Normal?

This pic shows some of the bottom leaves yellowing out - there are more pics in my album. Basically, these plants have been losing fan leaves on the bottom starting at 14 days. Some fan leaves are unaffected.

I had pulled off a bunch of wilted leaves before i took this pic, but you can see the yellowing leaves. I've been adding a bit of extra nitro and it doesn't seem to help.

The plants are pretty close together, so could they just be dropping the leaves that don't get much light?

I don't think it's a nitro deficiency - but i'll keep an open mind

I have fungus gnats.

the tops of the plants look beautiful, and they seem on track growth-wise.



Above pic is at 23 days, 9 days after i started losing leaves. I've probably remove 45 dead fan leaves from these plants. Just wondering how worried I should be or if this is normal.

it does look like a N deficiency to me, its normal in a sense.. that a plant will eat its older leaves to move N upto the new growth. by adding N you should slow the rate at which it does that and even get close to halting it. imo you can add a good amount more. do be aware that you should allow the plant to start eating itself of N at about 2weeks before harvest.

You caught it pretty early so it shouldn't be an issue. Hit them with a little N and Mg on top of your usual ferts and that should hold them over for a few more weeks. After that it is good for a plant to use up stored energy nearing the end of it's life.

if you have fungus gnats then you probably have fungus gnat larvae. foaf thinks the deficiencies you are seeing in the plants could be caused by the larvae of fungus gnats. the larvae can eat roots, spread phytium, and cause phantom nutrient deficiencies. any part of the root system that is getting affected by the larvae will show on the top of the plant where those roots where sending water/nutes to. you are going to want to kill the larvae immediately, probably look into mosquito dunks or liquid BTI, and maybe some pyrethrins to kill the adults, since you are in flower and should not use anything systemic like imidacloprid.

foaf has plants in veg do the same thing with dying bottom leaves and the same yellowing of the leaf, showing nitrogen and magnesium deficiencies. since foaf was in veg he used imidacloprid and liquid BTI combo. a day after the application, dead larvae came out of the bottom of the pots after an irrigation. foaf was surprised at how much larvae there was because the there were not many adult fungus gnats flying around. the treatment killed the larvae, and flushing then letting the medium dry out until the plant lower branches began to wilt, really helped things get back on track as far as nutrient uptake.

peace

Thanks a lot guys, I'll add some more nitro and we'll go from there. I'm already fighting the gnats (I think with success) and they should be at a manageable population now. I'll post more pics in a week or so and we can evaluate results. thanks!