Help-- plants not looking so good-- about 10-14 days away from flowering

Ok, I read all the info I could find on sick plants, but I'm still having some trouble figuring out how to get my plants back to healthy (and buds bigger) and not f**ing anything up.

Setup: 3 white widow plants, indoor grow, about 6 1/2 weeks into flowering, in MG moisture control soil (all I could find) under soft white flouro tubes. Used MG Bloom Booster every 10 days for flowering cycle, gave it a little more than recommended. Also foliar fed them a few times...

Switched to molasses after plants starting showing signs of necrotic (brown to orange-ish) veins on fan leaves, clawing, raised margins and burnt leaf tips (some tips now curling up slightly).

Necrosis has spread to interveinal spots and more leaves in the last week or so, but seems to be holding off (I think) since I used only pure water instead of the last scheduled fertilizing.

Also, a number of larger fan leaves have been drooping, especially w/ one of the smaller plants that looks to be farther ahead in flowering. She is showing the worst of it. These are the pics from that plant; the drooping looks like a symptom of overwatering (at least to my untrained eye).

But I'm currently only using about 1 gallon total to water these girls-- which is now about once every 5-6 days. Isn't that below avg.? Will it f*** up the plants if I use a lot more to flush?

(Also-- my camera made the plants appear a lighter shade of green than they actually are...the brown/dead spots are actually worse than they look)

Other possibly relevant info: I had an infestation of fungus gnats, which I'm treating w/ a sticky trap and by covering the surface of the soil w/ sand. Upper leaves look to have a deep green, almost dull-bluish tint, plus older stems are reddish--possible potassium deficiency? Are some nutes getting locked out by the MG? Also, only upper leaves are showing necrosis...

Thanks in advance for wisdom & advice. Definitely much needed, this is my first grow...

Sorry, here are the photos.

have you solved the gnat problem completely?

I just covered the soil w/ sand a couple days ago. Hoping it will suffocate the larvae, assuming that they are breeding in the soil and not somewhere else... I'll see the occasional gnat flying around, but none I can see in the growing area at present. The hanging sticky trap is covered w/ them.

I can also see an occasional fan leaf (maybe 1-2 per plant) on the bottom of the plant that's showing a nute deficiency for sure-- dead, burnt leaf, followed by yellowing, progressing from the tip towards the stem. K or P, maybe? Not a widespread problem yet.

Guess this is what I get for using MG...

I'm using the same soil. How far along did you say the grow was? We might be at the same point in the grow cycle? Maybe we can help one another.

I am getting close to harvest, I think-- 2 weeks if I had to guess. One plant might be ready before then.

My first time growing so this is still all guess work, pretty much.

I think that the MG or the fertilizer I used might be locking some nutrients out, but I'm worried that if some fan leaves are drooping (overwatering?), flushing will only make that worse.

Still a gnat or two flying around, but theyre not supposed to be a major problem (compared to spider mites, etc.).

I am worried that sick plants will lead to a shitty harvest.

Help, anyone? Can anyone tell by the pics if this is overwatering? And what kind of nute def/burn is going on? I am totally lost here.

Here are some more pics.

The necrosis & yellow veins you can see in the first pic, the dead leaf/yellowing in the second two.

Two different problems or the same? Nute burn or deficiency or both? Please Help...

im having thew same problem but mine seems to be muhc worse hopefuly you figure it out idk what to do about mine its at 9 weeks and getting very close to hrvest if you find a solution please let me know i tried some molassis and epsom salt and low dose firt today hopefully itll show in the next few days

new ww grower said:

I just covered the soil w/ sand a couple days ago. Hoping it will suffocate the larvae, assuming that they are breeding in the soil and not somewhere else... I'll see the occasional gnat flying around, but none I can see in the growing area at present. The hanging sticky trap is covered w/ them.

I can also see an occasional fan leaf (maybe 1-2 per plant) on the bottom of the plant that's showing a nute deficiency for sure-- dead, burnt leaf, followed by yellowing, progressing from the tip towards the stem. K or P, maybe? Not a widespread problem yet.

Guess this is what I get for using MG...

Click to expand...

Are the stems weak/breaking off easily?? Cus this was happening to mine, and it had some necrosis and red stems like yours, and the tips of the leaves were turning yellow, which means it's a Potassium deficiency. I added some Potash and I think it should take care of the problem. I also had fungus gnats. I would definitely flush first if I were you though, do it with lots of water, then just let them dry thoroughly before the next time you water them, you want to try to get any built up nutrients/salts out of there. That's my best guess, good luck!

whats potash ? and can you add it to hydro? i have the same problem but its not thay bad