Leaves crinkled downwards with brown spots on underside of main leaf veins.

[NEED 4 SEED]

Hi, I am having this problem with downwards crinkled leaves on some seed plants. They are all crosses of my own mother plants, no foreign clones involved. The moms don't have it too.
The leaves that are looking crinkled have these brown spots on the underside of the central leaf veins.
No insects at the moment but I had thrips and used a formula containing pyrethrine dissolved in vegetable oil two times on them with

lights out for several hours after.
To me the plants also seem to grow a bit slower than usual and not using up water as fast as expected (one time watering per week only or even less). So what can it be?

 

[therevverend]

Hemp Russet Mites are a possibility. Might have spotted one in the lower part of the blown up leaf picture, next to the middle petiole. They go for the petioles and cause leaf curling. Your treatment may have kept them at bay but they're very hard to eliminate. They don't make webbing like spider mites so they're much harder to spot. I'd get a loup or magnifying glass and do a search. Wouldn't treat without a positive ID.

Other than that I've got nothing specific, I'd do a checklist of the usual suspects. Over/underwatering, inspect the roots for fungus, the surface of the soil for flies, root aphids, and other soil pests. Hopefully it's not some sort of evil virus, curly top or something. Whatever it is, even if they snap out of it, let us know you've piqued my curiosity.

 

[Creeperpark]

You can see the mites on the leaf under-stems on the bottom of the leaves.

 

[NEED 4 SEED]

Ok, I took a microscope and searched for anything living or moving and there was nothing to be found. I also went and looked for my mother plants and two of them had one or two leaves with this look and also the brown spots on their main veins. What they have in common is a thrips infestation and the following treatment with the pyrethrine insecticide. Though, they are in separate locations. Also nothing to be found on stems. I hoped I could post the videos of my microscope examination but didn't find out how. So I'll post a screenshot of one of the brown spots.

 

[NEED 4 SEED]

You can see the mites on the leaf under-stems on the bottom of the leaves.

Can you show exactly what you mean?

 

[NEED 4 SEED]

Hemp Russet Mites are a possibility. Might have spotted one in the lower part of the blown up leaf picture, next to the middle petiole. They go for the petioles and cause leaf curling. Your treatment may have kept them at bay but they're very hard to eliminate. They don't make webbing like spider mites so they're much harder to spot. I'd get a loup or magnifying glass and do a search. Wouldn't treat without a positive ID.

Other than that I've got nothing specific, I'd do a checklist of the usual suspects. Over/underwatering, inspect the roots for fungus, the surface of the soil for flies, root aphids, and other soil pests. Hopefully it's not some sort of evil virus, curly top or something. Whatever it is, even if they snap out of it, let us know you've piqued my curiosity.

Thank u for the ideas. I'm positive that its not overwatering as I waited very long between watering, always lifting pots. But as I said it took very long for them to use up the water. Maybe partial underwatering as the upper part of the soil was pretty dry while the pots still being heavy. I also went back to the exact leaf to look for the supposed hemp russet mite you thought you spotted but the thing was gone. Tomorrow when light is on I will check for the soil. Thanks again for the great input.

 

[Creeperpark]

Can you show exactly what you mean?

If you looked all over the plant with a magnifier and didn't see anything I take your word for it. I have vision issues and have to look thru a CCTV screen. I'm glad to know I was wrong about the mites.

Water always follows salt in chemistry and so your plant's tips are getting sucked back in from this chemistry law. As your plants dry the excess salts in the soil are pulling the water back from the growing shoots. The problem is somewhere in your soil, you may have dry pockets or spots. You may not be giving enough water to your plants.

You need to learn what your water-holding capacity is for your containers. Water until you just start to get run-off and stop. Measure the amount you used and then monitor your water usage. If you don't know the water-holding capacity of the container you may be underwatering.

 

[NEED 4 SEED]

If you looked all over the plant with a magnifier and didn't see anything I take your word for it. I have vision issues and have to look thru a CCTV screen. I'm glad to know I was wrong about the mites.

Water always follows salt in chemistry and so your plant's tips are getting sucked back in from this chemistry law. As your plants dry the excess salts in the soil are pulling the water back from the growing shoots. The problem is somewhere in your soil, you may have dry pockets or spots. You may not be giving enough water to your plants.

You need to learn what your water-holding capacity is for your containers. Water until you just start to get run-off and stop. Measure the amount you used and then monitor your water usage. If you don't know the water-holding capacity of the container you may be underwatering.

Interesting, I'll take that into account.

 

[NEED 4 SEED]

Took a picture of the soil today and nothing to worry about. Right?

 

[therevverend]

Looks good, healthy roots, not miserably rootbound, no fungus growing on them, seems to be loose enough for water to drain through it instead of getting water-logged. I'm curious about this because I've had similar curling in my plants, 5-7 years ago. I've been thinking it through, started writing a response and some of the memories came back. What happened was my grape ape x bubblegum is a hog, always wants more nutrients. I had problems with both curling and variegation, I fixed it by adding micronutrients and P and K. Plants don't all need the same nutrients in the same amount. Every strain is different. Some are super picky, show signs easier than others. But when you fix the major obvious problem you fix the other plants' lockups and they go crazy. Not only did it fix the obvious symptoms in the grape ape x bubblegum it showed me I had a deficiency I didn't know I had in my other plants.

I started adding stuff like fish bone meal, alfalfa meal, various combinations of stuff that contained calcium, phosphate, potassium, mag, etc. I was already doing that but I got more systematic about it. A lot of people talk about epsom salts, sure it's good and can help but it's for beginners. There's a lot of other stuff plants need. It's a matter of having your plants slowly growing along vs really kicking ass and growing great stuff. It could be that your plants were good for a while but depleted a combination of micronutrients. The guides that show deficiencies are misleading because they show you extreme cases where the plant is truly fucked. Mild cases of deficiency are easy to miss.

It could still be something like root aphids, broad mites, or some other pest but it seems unlikely since you've thoroughly inspected the plants. They can be sneaky, all it takes is one batch of eggs to hatch to cause you misery. Another possibility is PH. Sometimes it's your soil mix. Sometimes you try something new or a brand switches their recipe and things get messed up for a while. Growing is never easy, there's always something to keep you busy. You can never stop learning.

 

[Creeperpark]

Fertilizers will not burn or damage plants if they are applied correctly. Fertilizers are salts much like table salt, except that they contain various essential plant nutrients. When a fertilizer is applied to a soil, nearby water begins to move very gradually toward the area where the fertilizer has been applied. Fertilizer salts begin to diffuse, or move away from the place where they were applied. This dilutes the fertilizer and distributes it throughout a much larger area.

If tender plant roots are close to the placement of a fertilizer, water is drawn from these roots, as well as from surrounding soil. The more salt or fertilizer applied, the more water is drawn from nearby roots. As water is drawn from the roots, plant cells begin to dehydrate and collapse and the plant roots burn or dehydrate to a point where they cannot recover. If soil moisture is limited, most of the water drawn toward the salt will come from the plant roots and leaves and the damage can be severe. So make sure your media is watered well to prevent clawing.

The turning inward of the leaves in the top photo indicates this.

 

[NEED 4 SEED]

So, I've been looking for my mother plants today after I had to treat them with pyrethrine a few days ago and I believe now that this treatment is the source of the crinkled leaves. I suppose it could have to do with using double the strength of the pesticide as said on the bottle. Next time I will lower that dose again, to see what happens. To finalize this I will add two pics. The first one is from right before the treatment and the second one is from today where you see some pretty identical damage. Of course I have been keeping the treated plants in darkness until they had been dried up and for the last days I kept the light on low intensity and hung it as high as possible. But that wasn't enough, obviously.

 

[NEED 4 SEED]

Ok pic upload is making errors. Will update later with pics.

 

[Loc Dog]

Ok pic upload is making errors. Will update later with pics.

Did you ever find the problem? Did the plants survive??? I just got burned by seed canary and prestige clones on strainly. Both had sales and both sets of clones had advanced stem canker which occurs from mold infected mothers. It can also get in through wounds or cutting tools that were not sterilized. If from mother or cloning it works from bottom up. If from topping from top down. Symptoms look like root rot but roots are healthy.

 

[NEED 4 SEED]

Did you ever find the problem? Did the plants survive??? I just got burned by seed canary and prestige clones on strainly. Both had sales and both sets of clones had advanced stem canker which occurs from mold infected mothers. It can also get in through wounds or cutting tools that were not sterilized. If from mother or cloning it works from bottom up. If from topping from top down. Symptoms look like root rot but roots are healthy.

I think it was a too high dose of pyrethrine combined with too much dish washing soap.

 

[TanzanianMagic]

No insects at the moment but I had thrips

There is one thrip on the left image, and the dots I think could still have something to do with mites.

The damaged leaf edges are likely because of insect damage.

 

[NEED 4 SEED]

There is one thrip on the left image, and the dots I think could still have something to do with mites.

The damaged leaf edges are likely because of insect damage.

The plants are long gone and no such issues again. Thanks anyway.