Sick plants - Is this N tox?

[gnusmas]

Hi there!

Around 14 days ago, a couple of weeks after transplanting, I dropped a few NPK fertiliser granules on the soil surface for the nutes to be carried down by irrigation. It has since rained heavily and the pellets have dissolved completely.

Everything was fine when I checked 4 days ago, except for a couple of white flies I found around the plants. I sprayed a very weak soap solution on them to kill off the fly. I think this is unrelated to the curled leaf problem I am having as shown in the pictured below.

Did some googling and am suspecting N tox, but I wanted to be sure before taking action. Any advice apprciated. Thanks!

Also note the drying out leaf in the last image.

 

[Atulip]

The leaves look too light in color to be nitrogen toxicity. The drooping looks more like over watering.

The brown leaves on older growth look most like phosphorus deficiency to me.

Cannabis Plant and Pest Problem Solver - Pictorial

 

[gnusmas]

Does over-watering make the leaves claw up in this way too? Thanks for your help.

 

[Novatokeman]

do you have a ph tester? they look like you have over watered with fire water... id try adding a few more holes and letting the pot dry out then give a good watering of 6.5...

 

[Atulip]

Does over-watering make the leaves claw up in this way too? Thanks for your help.

Just looks like they're drooping to me. You could also check your runoff ph that might cause deficiency. And you can flush it good if you're worried about toxicity.

 

[gnusmas]

Just looks like they're drooping to me. You could also check your runoff ph that might cause deficiency. And you can flush it good if you're worried about toxicity.

I don't think it's simply drooping as several of the leaves are twisted and deformed and cannot be straightened back without breaking them. At the top of the first picture in the OP, you can see a leaf that is twisted sideways and up. I should have taken better photos because there are quite a few leaves like that and others that look like a hook.

do you have a ph tester? they look like you have over watered with fire water... id try adding a few more holes and letting the pot dry out then give a good watering of 6.5...

Don't have a PH tester but I can try and get my hands on one. The water is irrigation water so I don't know what's in it. Thanks for the tips.

 

[Thekungfufarm]

The leaves twisting and deformed like that are almost entirely a ph issue. The water is far too alkaline. If it is irrigation or well water, it will have a very large amount of dissolved solids, ie: Minerals. This raises the ph of the water. Compounding the problem is the fertilizer. They are over fed and toxic. Go get some RO or distilled water and flush with 2x the volume of the pot. Example: 3 gallon pot, flush with 6 gallons of water. Beg, borrow or steal a ph meter. In soil, the ph should range from 6.0-6.5. Flush and flush again. Then wait. Give her no more nutes of any kind. If you must put something in the water, find a mycorrhizae booster. They are microscopic organisms that attach to the roots of the plants helping it draw nutrients from the soil. Ph the water going in. Ph the water coming out. Going in should be acidic, coming out, should be around 6.8-7.

 

[iwltfum]

Look into russet/broad mites and check for them. It looks like the damage on your leaves is very similar to the damage that russets cause.
Here's a recent thread on the topic of broad mites (very similar to russets): Broad Mite. I posted some pictures in post#3 of what russet mite damage looks like

 

[Thekungfufarm]

I would correct the grow conditions first, address any pest issues second. Pests don't do much damage if the plant is healthy. *If* the issue is pests, Azamax is your best bet. Won't burn the leaves. Also: Make sure the pot has good drainage. If not, drill more holes in the bottom, or invest in fabric pots. Oxygen flow to roots is incredibly important. I have had this exact thing happen to me early in my grow career. Turns out, my ph meter wasn't working properly & the water was either far too alkaline or too acidic. I replaced the meter, flushed the plant & re-potted the plant in fresh medium. Give it a day or so and top the plant to the 3rd node up from the bottom. That will force new growth.

 

[iwltfum]

I would correct the grow conditions first, address any pest issues second. Pests don't do much damage if the plant is healthy. *If* the issue is pests, Azamax is your best bet. Won't burn the leaves. Also: Make sure the pot has good drainage. If not, drill more holes in the bottom, or invest in fabric pots. Oxygen flow to roots is incredibly important. I have had this exact thing happen to me early in my grow career. Turns out, my ph meter wasn't working properly & the water was either far too alkaline or too acidic. I replaced the meter, flushed the plant & re-potted the plant in fresh medium. Give it a day or so and top the plant to the 3rd node up from the bottom. That will force new growth.

These mites don't really care if the plant is healthy or not. Azamax has actually been shown to increase their numbers and strength.

Gnusmas: It very well may not be russet or broad mites, but I would check them out and make sure that's not what's going on just to be safe, because if it is them, then you have a serious infestation and you will want to get on that immediately. They are some of the biggest headache causers in the pest world and you don't want to procrastinate.

 

[Thekungfufarm]

These mites don't really care if the plant is healthy or not. Azamax has actually been shown to increase their numbers and strength.

Gnusmas: It very well may not be russet or broad mites, but I would check them out and make sure that's not what's going on just to be safe, because if it is them, then you have a serious infestation and you will want to get on that immediately. They are some of the biggest headache causers in the pest world and you don't want to procrastinate.

Good point. Broad mite is the one thing I have never had to deal with as I keep my grow areas spotless and sealed. Frankly, if they are that hard to get rid of, I would toss the whole mess and start over with sterilized equipment. Given that they are microscopic, there is no way to be absolutely sure they are all dead. But then, I don't have the patience nor the time as a commercial grower to mess around with a bunch of infested plants.

 

[iwltfum]

It's more that people don't know how to control them. They usually start out thinking it's N toxicity so they spend a week or two ruling that out, and then they try normal bug stuff like azamax or spinosad. That just seems to make things worse than before somehow. And by that time, the infestation is in full swing and much harder to take care of. I work for a commercial grower and we have had to deal with them several times. Cutting the entire crop would have been way too big of a loss for the company. Sulfur dioxide or pyrethium foggers work the best.

 

[Thekungfufarm]

Pyrethrum definitely has a wide range of action. The only issue with that is that there are some folks (like me) that are deathly allergic to pyrethrum and its derivatives. This is definitely something I would not use on ingestible plant material that cannot be washed off. Were it me, I would move more toward a CO2 flood or a heat treatment (115 or so degrees for about 20 minutes once a week until population is wiped out). But then, I am a strict organic grower and I tend to look at environmental issues first.

 

[gnusmas]

Thanks again everyone for all the advice and interesting discussion.

I've flushed the pots and will wait for them to dry out. I'm fairly sure it's not mites or critters as the plants look very clean in general and another nearby plant has no similar damage.

Is there any alternative PH test (one time use strips, maybe) to a PH meter as I don't think I'll be able to get one soon enough? I'm going away for some days next week and will have to leave the grow to its own devices for that period.

 

[Thekungfufarm]

Pet stores that carry fish have liquid ph test kits that are better than the strips. Not as accurate as a meter, but better than nothing.

 

[Novatokeman]

Pet stores that carry fish have liquid ph test kits that are better than the strips. Not as accurate as a meter, but better than nothing.

i looked at those kits at "petsmart" and my local grow shop had a proper agro water testing kit and it was cheaper by a lot with quite a bit more testing liquid in the package. In this case anything is better than nothing.