Went to 12/12 a few days ago.

Was just using water, until today when I used 1ml grow and bloom.

Although one plant has looked decidedly poorly, and when I came back from being away for 3 days it looked pretty bad.

Yellowing leaves and black(ish) patches, leaves are crisping and dying.

This is a Thai Widow, and I have 2, the other seems fine (I have pics).

Lights on 28 degrees. Off 17 degrees or so.

Humidity 40-70%. Lights are foot and a half away.

Anyone help?

Here's a pic:

Here's another:

And here's a pic of the other plant which is OK, but may have signs developing:

Some fungal infection of sorts - i'd remove those dead leaves, & cut back to healthy tissue any other infected leaves. And then treat with a fungicide - good luck with it & hope it doesn't spread vigorously.

Uh, oh

Any idea of a good spray to use, that's relatively easy to get off the shelf?

before i started using apsom salts, Mg def showed up by day 21 into flowering, i start feeding epsom salts starting week 2 flowering, i know your not that far in, but it looks like Mg def. you can spray epsom salts for a quick fix, cut the dead stuff off.

It certainly don't look like an Mg def to me either, grandad - it looks like it may be LSF - something fungal, at any rate...

Copper Sulphate-containing sprays have worked well for other people who have suffered from LSF in veg, AFAICR...

i just had a bad battle with fungus, for it to be fungus, you need check walls and ceiling, it has to come from somewhere, unless you left water on leaves when lights go out.

i have a grow diary, my battle with fungus lasted 10 years, came from cavity wall, i had black mould on walls and ceiling in 3 rooms, one was grow room, the fungus was in wallpaper and carpets, floor tiles, furniture, fungus is far worse than spider mites. now i fixed the fungus, i realise i had N and Mg def. all fixed now, near forgot mention, with fungus comes bugs..

Fungus spores are everywhere. They don't have to come from a damp wall or floors. If you haven't got good ventilation you will be a lot more susceptible to infection - but even blowing a gale through your room is no guarantee of protection. With our ever milder seasons infections are becoming more prevalent. OT1 mentioned that the best defence against attack is vigourous growth.

I've used copper when in Veg and up to a week or so in flower. I'm not sure how long into flower you can use copper. It's reated as organic by the soil association, and people spray it on fruit and veg thoughout the growing season. But I don't know what the effects of smoking it would be. Because of this doubt, I use trichoderma foliar spray one flowering is established.

Bajer

I went into flower 6 days ago.

I'm gonna use the copper based stuff as mentioned, will go out and find some today.

I presume they should be misted with lights off to prevent leaf burn?

Yes, also it is better to do it with the lights off because you don't really want to accidently spray a grow bulb whilst it is on .

H.T.

Yep looks fungal, same sorta thing i've had a few times, take the badly affected leaves off and you should be fine, seems a few guys like this trichoderma carry on and apparently it's a very good preventative, but from reading up on as many threads as possible on this, to find a suitable combatant for future occurances in my grow, i found that alot of ppl rate "fungus Fighter" from BnQ, some ppl like "citrofresh" some h8 it and say it made things worse, some ppl rate "murphy's copper" some say it killed their plants, but no one has said fungus fighter has caused any problems and clears it up nicely, process of elimination that makes it the easiest and cheapest solution. IMO.

If you can be bothered with the messing about and buying 3/4 products to make your own spray, there is a good thread on Trichoderma and VAM's on these boards, GL.

it defo looks like L.S.F. to me, ive been battling this for years. Tried many different things to try combat it, sprays, moved house, burnt all my grow gear and started again and new genetics. Till i found the fun with fungi thread on here, i treat my plants with canna trichoderma and increased my ventilation. Touch wood ive had no problems since. Also when i first got trichoderma i wasnt applying it properly, look in the fun with fungi thread for the bit where old timer tells you of the correct application.
Goodluck mate hope you win the battle n get it sorted..

Greenmonster