Strange issue - Tiger striped leaves?!

[Life_On_Mars]

Hi all. Got an odd one here. I've got 6 Ugorg #1's in 10L canna coco/perlite hempy buckets. Nutrients are canna vega. They were vegged for about 2 months and have been in flower for a week. They've been getting the full strength feed of veg nutes from the canna chart - 2ml/L.

I noticed these issues about a week ago on three of the plants. The two largest plants are not affected, they are also a darker green. It is an odd issue, like dark brown/purple stripes in between the veins, with the leaf eventually crisping up and dying.

I defoliated quite hard pre-flower, before this occurred, I'd be surprised if that's what caused it though. The feed before this happened I did add too much PH down, and had to add PH up to compensate, quite a bit of it, so I had assumed that's what had caused this, but they've had a flush and a couple of feeds since then and I'm still seeing the issue popping up on these three plants.

Looks like a PH issue, I know, but I've checked the PH of the runoff, flushed and refed with freshly PH'd water/nutes, but it's still popping up. I've also checked my PH pen calibration, it seems to be fine.

I am letting the pots dry out a fair bit between watering's. The plants aren't full on wilting, but they're very light when I water. I doubt that is anything to do with it, but I do wonder if this is a reaction to the 'res' being empty for a day or so before refeeding. It doesn't make sense why the larger plants aren't affected though.

I had some great help here a while back from @Waira and @Mañ'O'Green so I'm hoping I can get some more assistance.

LED's off, flash pic of a leaf -

Top left and bottom right are unaffected.

Cheers!

 

[Life_On_Mars]

Some more info - Light is a 450w QB style LED. Temps have been 22-26c, RH has been around 60%. I have pretty hard water, so I've been using the hard water version of the canna nutes. Also they were in 1L mini hempys under T5's for the first 6 weeks or so, and they were transplanted into these larger ones and moved into the LED tent about 3 weeks ago.

 

[namvet25]

Could be lock out with phos def and also mag def. If possible flush with cal/mag and give them a dose of bloom nutes with higher phos.Try and get your ph close to 6.5.

 

[Mañ'O'Green]

@Life_On_Mars Your plants look overall hungry and have a magnesium problem. Too Much or too little?

Read this and then get back to me about how you are feeding them. Transplanting Autos is not a good idea and can cause issues.

Tutorial - A word on Nutrients

The proper use of “salt” based fertilizer to grow Auto Flowering Cannabis. Salts: Natural and man made any chemical compound formed from the reaction of an acid with a base, with all or part of the hydrogen of the acid replaced by a metal or other cation. Learning how to use salt based...

www.autoflower.org

You may also be letting your pots dry down too far?

What you need to learn about watering will come with practice. Here are the basic rules: Never let the soil dry out. Soil and or coco can become hydrophobic if allowed to dry. This means it repels water. This in turn will create dry pockets in the soil and the roots and microbes will die there. If your soil - coco have accidentally dried out use a surfactant to help re-wet it. I like yucca powder. Don't let soil remain soggy by watering too much too often. Root rot, damping off, molds, fungus gnats and other problems start in soggy soil. When you do water water the entire pot. How to learn when to water starts before you plant the seed. Fill your container with fresh soil/coco and weigh it (heft it) this is the lightest weight and consider it a dry pot. Now slowly water until the soil/coco will no longer absorb the water and run-off begins; weigh the pot (heft it) this is the maximum water, the wettest the pot can get. The difference between wettest and driest is the maximum water weight, for ease of explanation lets just say the water weighs 20 pounds. When the pot loses 10 pounds (half of the water weight) it is time to water again. There is an art to watering.

 

[Life_On_Mars]

Thanks ppl.

@Mañ'O'Green they're photoperiods, I should have clarified. I'm asking here as I've had great help here in the past, hopefully that's OK. Thanks for the link. At lot of good info there.

I'm feeding them canna hydro nutrients as I read it's best to use hydro nutrients in hempy buckets. I've just been following the recommended feed chart from Canna, and feeding every time. I've been PH-ing to around 5.9, but I think my PH pen may been slightly off (just recalibrated it again last night) and they may have been getting fed closer to 5PH. When I first saw this issue pop up I flushed the effected plants with plain water and refed with a weak solution, as I actually thought it was nute burn (it looked a bit like that at first). This actually seemed to make the problem worse, and since giving them a normal half strength feed of flower nutrients last night, the problem hasn't progressed any further today.

The thing is, because they were moved from small 1L hempies (that they were in for a bit too long) straight into 10l hempies, I was being a bit conservative with watering for the first week or so, especially on the smaller plants that weren't drinking as much (the ones that are now affected) as I was worried about root rot with all that water in the hempy 'res' and sodden coco/perlite sitting in the warm grow tent. Obviously with synthetic nutrients, less watering = less feed. Perhaps I do just need to up the feed. As I said, I've been growing organically in soil up until now, so it's a bit of learning curve.

Mag def would also make sense as I'm using HW nutes (which I assume have a reduced cal and mag amount) as I have hard water which is high in calcium, but it's not super high in mag according to my local water report. I've never seen a mag def show like this though? It's always lightening between the veins whenever I've had it/seen pics, not darkening.

Perhaps I should add some epsoms in with the next feed. I've typically used 1tbsp per gallon added to the water when my plants need mag in the past, but that was with plain water. I assume the Canna HW Flores nutrients also contain some mag, so perhaps I should just add half a tbsp per gallon to my nutrient solution?

I do think I've been letting them over dry. All my grows have been soil up until this one, and I always had issues with overwatering, so I'm wary of it. Plus both times these issues popped up it was on the last day just before watering. I fed/watered them last night and it hasn't gotten worse today, so I think I might just carry on as normal, just watering a day earlier. Just weird that the bigger plants that are drinking faster aren't showing any issues.

 

[Mañ'O'Green]

Ok then PH 5.0 can and will cause what you are seeing. You are watering coco like soil. It is not soil. You must not let it dry out at all. It will become hydrophobic. It is hard as hell to get wet again if that happens. Use a surfactant like yucca powder to re-wet the pot. Coco should be fertigated every time you water to 20% run-off to waste. 1g Epsom salt will provide 54 PPM of magnesium and 72 PPM of sulfur in 1 gallon of water. This would be plenty to add to the other nutrients just one time! A tablespoon = ~15g of Epsom salt that is way way too much.

edit: 1g /gal of Epsom =54 PPM of magnesium and 72 PPM of sulfur.

 

[North Forge]

Yeah a hempy bucket isn't like soil which goes through wet and dry cycles. A hempy bucket is just a low Tek hydroponics. You can't overwater in that system, and you want that bottom reservoir full of water. If it's dry down there the roots will just air prune themselves.

 

[Life_On_Mars]

Ok, good to know. It hasn't become hydrophobic. Even though I'm waiting till they're light before watering, it's only the top layer of coco that's actually touch dry, just under the surface is still damp.

So - don't water when the bucket feels light (3 days) water when the res is empty even though the coco/perlite is well saturated with water? (1-2 days).

I was going to flush them again today, but seeing the damage seems to have stopped spreading I think I'm just going to keep calm and carry on, just trying to water/feed more frequently.

Epsom salt will provide 54 PPM of magnesium and 72 PPM of sulfur in 1 gallon of water.

Is there a measurement missing here? Did you mean 1 tsp of Epsom will provide...?
I think I'm going to leave the epsoms for now and trust that upping the watering/feeding frequency of a balanced bloom nutrient formula will provide what they need (as per the recommendation in the helpful link you provided). If I still see issues in a week after continuing with that, then I'll assume the HW formula+my tap water is not providing enough mag, and try the epsoms.

Thanks everyone for your help. I frequent a few of these growing forums and this is always the place I'm most likely to find reliable, helpful answers.

 

[Mañ'O'Green]

Ok, good to know. It hasn't become hydrophobic. Even though I'm waiting till they're light before watering, it's only the top layer of coco that's actually touch dry, just under the surface is still damp.

So - don't water when the bucket feels light (3 days) water when the res is empty even though the coco/perlite is well saturated with water? (1-2 days).

I was going to flush them again today, but seeing the damage seems to have stopped spreading I think I'm just going to keep calm and carry on, just trying to water/feed more frequently.



Is there a measurement missing here? Did you mean 1 tsp of Epsom will provide...?
I think I'm going to leave the epsoms for now and trust that upping the watering/feeding frequency of a balanced bloom nutrient formula will provide what they need (as per the recommendation in the helpful link you provided). If I still see issues in a week after continuing with that, then I'll assume the HW formula+my tap water is not providing enough mag, and try the epsoms.

Thanks everyone for your help. I frequent a few of these growing forums and this is always the place I'm most likely to find reliable, helpful answers.

Yeah, 1g of Epsom = 54 PPM of magnesium and 72 PPM of sulfur in a gallon of water.

There are different strength/formulas for Epsom Salt the above is based on 9% magnesium and 12% Sulfur. It will be on the label. There is also always variation in the sample. These are good working numbers that will keep you in the game.

Mix the Epsom salt into the water first and make sure it is well mixed then add your regular Canna nutrients.

 

[North Forge]

So - don't water when the bucket feels light (3 days) water when the res is empty even though the coco/perlite is well saturated with water? (1-2 days).

You just want the Reservoir to be full of water by the time the roots reach down there. Very early on it doesn't matter as much. But once the roots are established More frequent waterings in coco or hempy buckets will almost always be better. It's a hydroponic medium.