Curled and dried up leave - help!

[stokesy]

My first grow. Arjans Strawberry Haze

This is one of 6 plants in the same tent, all getting the same treatment. 7 weeks from seed, 600w HPS, everything fine apart from about 8 leaves, all from the same part of the main stem..
I've examined the leaves with a loop, and there's no sign of insects - in fact - nothing untoward, apart from the curling and drying up. Rest of the plant is healthy.
I thought first of all that perhaps the leaves had gotten the noots when I last watered - but all the plants were watered the same, and this is the only one showing stress - just on these leaves. I've nipped them off at the stalk end, and they were really dry.

Any idea what could have caused this? I've noticed a couple of small flies in the tent when I move the plants for watering - that's the only other thing I can think of - but, like I said, the problem is very localised.

Thanks in advance!

The Stoke

 

[billmoe93]

Is it at the top or bottom of the plant?

Did you maybe accidentally spill some nutes directly on the leaves?

The flies are probably fungus gnats, the larvae can start messing up your roots if left unchecked. Getting rid of them is pretty easy though.

 

[stokesy]

The plant is heavily LST'd. The affected leaves were about half way up, had the plant been allowed to grow normally..
Spilling the nutes on the leaves.. if I had spilled any, I would have expected the others to have the same effects... I just sploshed it all on, not really taking care to avoid the foliage. I've taken more care, since then.
Fungus gnats? How do get rid of them?

Thanks a lot...!

 

[billmoe93]

For the gnats youre going to want to make sure you are dealing with gnats. This post will help you identify your invaders and provide a few solutions.

Cannabis Plant and Pest Problem Solver - Pictorial

I just dealt with some gnats and sprayed the plants, top of the soil and bottom of the pots with a neem oil solution every three days for a few weeks also killing the flyers. Its important to keep spraying even after you dont see any because they hatch every 4 days or so.

As for the 8 leaves, Im not sure. Maybe some wider shots might help some others help you diagnose. Maybe a close up of one of the affected leaves if they are not all gone

So Im assuming the grey cable wrapped around the plant is from the stressing technique? I wanna say overstressed maybe, but I feel like it would affect the branches above it as well. Do you know the soil Ph? Or the run off Ph?

 

[stokesy]

Billmoe,

Thanks.. I've removed the leaves, and there seems to be no re-occurrance of the problem.
I'll get to work on the insects... first thing, as you say, is to determine if they ARE gnats.
The grey cable is indeed the tie for the stressing. This same technique has been applied to all the plants, and all others are doing just fine.
Removed the dead leaves so - can't get any more shots.
In the meantime, I'll get the potato slices down.. that should determine if they are indeed gnats..

Thank you!

 

[stokesy]

Identified a gnat today. So - tomorrow - they get the Neem oil treatment. Is it best to spray them before lights out (they're on 12/12), or is it ok to spray during the day period? I have 6 of them under a 600w HPS lamp, with ample ventilation in and out..

Tks!

 

[billmoe93]

How far into flower are they? I didn't realize you were flowering, there might be better solutions for you other than spraying the neem. I was in veg when I had my infestation.

Spraying plants with stuff when they are flowering can lead to some problems. You could do a neem oil root drench. It is a systematic deal so it will work fine.

I usually sprayed at the very beginning of the day cycle in veg to give everything a chance to evaporate. Spraying right before nighttime can sometimes lead to the evil powder mold.

 

[stokesy]

I don't have any in flower yet - only switched them to 12/12 3 days ago (2nd. Jan) - so - that shouldn't present any probs - right? I first noticed the odd fly about 3 weeks ago (4 weeks from seed), but just put it down to ornery baby household fly..I realise I'll need to keep neeming for the length of the lifecycle.

Thanks!

 

[billmoe93]

Im pretty sure you are safe, however the problem with spraying is you wont necessarily know how long you will be spraying. If some of them survive and the cycle continues you could be spraying weeks into 12/12. This is why I might go with a drench over spraying. You might be able to get away with just spraying the top of the soil, the drainage holes and killing all the flyers if you believe it to be a minor infestation.

It poses concern to the end product when you are spraying stuff when the buds are growing. I know neem oil is safe, but I have read that you should to tell whoever is using the final product what you were spraying with while flowering. This led me to believe its probably not a good idea to be spraying during flowering. I could be wrong though.


Edit: I just remembered if you spray the plants with neem, its also a good idea to spray with plain water after to make sure the stomata is not clogged. So essentially you would be spraying them twice every three days in flower. It could get a little too moist.

 

[stokesy]

So.. how long in between the neem spray and the fresh water cleansing spray?
And what's the mix ratio? I read various different opinions - what do you use?

I just got mugged - paid 10 Euro for 30 mls of Neem Oil. (Last bottle in town) I know I can get it for a LOT less than that, (and have ordered it), but right now is my problem.

So..I'm ready to spray when i can get clear on the ratios water/neem/soap.

Thanks!

 

[billmoe93]

Spraying in between the neem and plain water: I just sprayed the neem, let it evaporate then go ahead and hit the plant again with the plain water. Making sure to get the underside of the leaves. So almost right after.


I was using a 70% neem oil product that had some other stuff in it. I honestly cant recall the ratio I used. I tried to find the thread I got my ratio from but couldn't. I kind of think you found it, if you read a post on here that said using neem oil without making the plants sticky. That is the thread I based my ratio off of. It sounds like you got 100% neem so finding a ratio should be easier.

 

[stokesy]

For those interested, here's the information for the correct use ...of Neem Oil.


Organic Neem Spray - Buy Or Make Your Own Neem Oil Spray?

I'm going with a .5% solution - 5mls oil to 1 litre water, with a small drop of liquid soap.
Off to deal with the problem now...

 

[stokesy]

Sprayed them well with Neem oil at .5% solution yesterday morning, and they look brilliant. No sign of any after effects, so I'm just going to leave them as they are right now, without spraying them with fresh water.
I've had a good look into Neem application, and nowhere does it mention that they should be rinsed afterwards. .5% is very small concentration, and when you consider the situation, once the water has evaporated, leaving the oil behind, it's gonna take a fair bit of clean water to remove the residual Neem oil.
So - unless anyone can come up with a good reason for after-spraying with clean water, I'm going with just the Neem spray. If there's any deterioration, or oiliness showing, I'll have a re-think.
I'm new to all this, so I'd like as many comments as i can get.!

Thanks!

 

[billmoe93]

Spraying the plain water is mostly a preventative. The only purpose of this is to make sure the stomata on the underside of the leaves dont get clogged. Its not about removing the oil. Its not always necessary but its good to know.

 

[stokesy]

Bill, Thanks! Just noticed a FLY in the tent today - so the first sweep hasn't got all the adults. Found dead one on a bit of potato though!