Stunted growth - a repeating problem I can not solve

[Emilya Green]

I think you're experiencing a misdiagnosis. What I see in the picture is a magnesium deficiency along with a potassium deficiency. I submit that instead of burning, your plants actually were having a deficiency. It is a common misconception that all leaf tip damage indicates overfeeding. This is so common among new growers that this is why I asked the question and wanted to see the picture of the plants in early bloom. PPM measurements are usually used in hydro and cocoa operations and not soil. Trust your new manufacturers recommendations and stop thinking that every bit of leaf damage is caused by overfeeding.

 

[Sparkey224]

Looks like ppms are fine.
Its hard to keep plants going in smaller plastic pot, especially in flower imo Getting the pots off the floor with "risers" would help too imo.
Can you replace them with fabric pots?
Just ideas, looks like a lot of work.

I run salts and usually have 20%runoff and wait for her to be bone dry again.
If running liquid organic nutes, barely any runoff like mentioned above.

 

[plan500]

I think you're experiencing a misdiagnosis. What I see in the picture is a magnesium deficiency along with a potassium deficiency. I submit that instead of burning, your plants actually were having a deficiency. It is a common misconception that all leaf tip damage indicates overfeeding. This is so common among new growers that this is why I asked the question and wanted to see the picture of the plants in early bloom. EC measurements are usually used in hydro and cocoa operations and not soil. Trust your new manufacturers recommendations and stop thinking that every bit of leaf damage is caused by overfeeding.

That was unexpected and hard to swallow. Let me clarify that first symptoms were yellowing of lower leaves and not tip burns. Judging by the ppms I was feeding and eventually runoff would you say I was underfeeding? If that is so I should through runoff checks out of the window. After the first symptoms I fed them 500ppm (2ml/l Agla bloom + 0.5ml/liter CalMag), and that didn't make things better. I am very confused at this point and not sure what to do.

 

[plan500]

Looks like ppms are fine.
Its hard to keep plants going in smaller plastic pot, especially in flower imo Getting the pots off the floor with "risers" would help too imo.
Can you replace them with fabric pots?
Just ideas, looks like a lot of work.

I run salts and usually have 20%runoff and wait for her to be bone dry again.
If running liquid organic nutes, barely any runoff like mentioned above.

The pots are fine, I've seen people that grow twice as big plants in those pots with success. Also I can not afford to have runoff as much as I want to. I need to be able to keep a balanced feed and not let the media get too hot. However now I am confused as to what rules to follow.

 

[Jonny5]

I m sure you will get a flood of response,, It’s a common mistake by growers, But when your plants look healthy and happy let them be. You can not force a plant to be what you conceive it should be,, when you are at that stage of your operation and think hmmm maybe I can do this , think again.. and if you go ahead with your decision, try it out on a couple/few plants first, this way you live and learn, was it good or bad, never subject your whole crop to experimentation ! When you are a new grower,, stick with the program that is,, It is a science with all the nutrients and such the industry gives you to play with so you have to think like a scientist if you’re going to change things up..I would have to side with emilya , if you’re using organic nutrients you would really have had to dose them to get burn, so you have flushed them and now you can give them a half feed keep them MOIST “and watch ... I really feel for you, It’s a Bastard when all the time and effort goes a little sideways..maybe Mel and Bill will chime in with some thoughts,

 

[Emilya Green]

That was unexpected and hard to swallow. Let me clarify that first symptoms were yellowing of lower leaves and not tip burns. Judging by the ppms I was feeding and eventually runoff would you say I was underfeeding? If that is so I should through runoff checks out of the window. After the first symptoms I fed them 500ppm (2ml/l Agla bloom + 0.5ml/liter CalMag), and that didn't make things better. I am very confused at this point and not sure what to do.

I need to confirm that you are growing in soil, and sorry, I just can't remember. I am trying to figure out where you came up with the low ppm number that you are trying to feed by.

You just strengthened my belief that you have been underfeeding. You said tip burns again, and I want to stress that I don't see a tip burn, I see instead an elongated necrosis at the tips, even to the point of curling. This is classic response to a potassium deficiency, since potassium is stored heavily in the tips and the margins of the leaf. The thing that cinched it for me though, was when you described how the problem first presented ... because you were scrimping on a macro nutrient, and that macro nutrient is mobile within the plant, to give the buds what they needed, the potassium was first taken from the storehouses in the lower leaves, and when they began to be drained, the plant started stealing from all over, even up top.

In soil, most people don't use ppms. It is confusing, and compared to other methods, the numbers that serve you well in hydro or coco, are not nearly enough for a soil grower. Soil is meant to be fed heavily, in a feed/water/feed/water situation. The soil will store half of the nutes that you supply on the feed pass, to be released to the plant on the water only pass. At 500 ppm, you are barely keeping these plants alive. In bloom, ppms over 1000 are not unreasonable, in soil. Not to give you heart palpitations or anything, but let me show you a snippet of the Fox Farm Nutrients Soil Feeding Schedule. Look at the PPM values near mid bloom that are over 2000!

Does your nutrient program have soil application instructions in so many ml or tsp per gallon? If they do, follow that instead, and I bet it is a gob more than you have been feeding.

 

[plan500]

I need to confirm that you are growing in soil, and sorry, I just can't remember. I am trying to figure out where you came up with the low ppm number that you are trying to feed by.

You just strengthened my belief that you have been underfeeding. You said tip burns again, and I want to stress that I don't see a tip burn, I see instead an elongated necrosis at the tips, even to the point of curling. This is classic response to a potassium deficiency, since potassium is stored heavily in the tips and the margins of the leaf. The thing that cinched it for me though, was when you described how the problem first presented ... because you were scrimping on a macro nutrient, and that macro nutrient is mobile within the plant, to give the buds what they needed, the potassium was first taken from the storehouses in the lower leaves, and when they began to be drained, the plant started stealing from all over, even up top.

In soil, most people don't use ppms. It is confusing, and compared to other methods, the numbers that serve you well in hydro or coco, are not nearly enough for a soil grower. Soil is meant to be fed heavily, in a feed/water/feed/water situation. The soil will store half of the nutes that you supply on the feed pass, to be released to the plant on the water only pass. At 500 ppm, you are barely keeping these plants alive. In bloom, ppms over 1000 are not unreasonable, in soil. Not to give you heart palpitations or anything, but let me show you a snippet of the Fox Farm Nutrients Soil Feeding Schedule. Look at the PPM values near mid bloom that are over 2000!

Does your nutrient program have soil application instructions in so many ml or tsp per gallon? If they do, follow that instead, and I bet it is a gob more than you have been feeding.

If all this turn out to be right, then you probably just saved my life, as I would have easily wasted another couple of batches and probably never realize the problem.

Yes, I grow in Plagron Lightmix which is technically peat not exactly dirt, but I assume it falls under soils.

It now makes sense why the plants are so light and instead of classical tip burns and dark leaves (nitrogen toxicity) the tips are curling and drying off. Also my actions in terms of flushing have actually made things worst so far. I though its gets worst from the remaining ppm in the media and a possible lockout but I was wrong. Also the plants deteriorated so quickly that and evenly (all of them) that it makes more sense to be underfeeding than over.

Now back to the root of the problem - the nutes strength. I work with the 500 Hanna scale which means that 500ppm = 1 EC, also my feeding schedule is Feed-Feed-Feed-Feed which technically makes my feed a 900-1000ppm compared to Feed-Water-Feed-Water. I know that this is getting rather specific from that point on so I will make another post with more info and hopefully someone can give me an idea of where I should be.

Can't thank you enough for this input, it is a real life saver.

 

[plan500]

I have decided to change my model to SOG, increasing the number of plants and keeping them with no topping, 4 weeks veg from seed and 9 weeks flowering period. Here is what the calculator from Plagron suggests for that model with a few things to consider.

1. My soil is not Promix (unfertilized) but Lightmix (fertilized) so there are some mineral nutrients for one week or so.

2. PPM of the main nutes are approximately as following: (Hanna 500 scale)

- Alga Grow or Bloom = 200ppm/ml
- Green sensation = 300ppm/ml
- Power roots = 20ppm/ml
- Calmag (another brand, not included in this chart) = 200ppm/ml

3. I don't use sugar royal.

4. Also, they suggest that I feed with every watering, which makes what already appears a lot, double compared to Feed-Water-Feed-Water model.

Can anyone comment on this chart and has anyone have experience with this specific brand? I can't even confirm whether this feed chart applies to cannabis. The nutes are organic, derived from algae.

 

[Emilya Green]

so, up until now, you have been following this system. You see the results. Double everything for 2 weeks and see what happens. You have nothing to lose. As you said, you don't even know if that system is for petunias or fruiting budding weeds like ours.

 

[plan500]

so, up until now, you have been following this system. You see the results. Double everything for 2 weeks and see what happens. You have nothing to lose. As you said, you don't even know if that system is for petunias or fruiting budding weeds like ours.

For my next batch I will divided the plants into two groups and start feeding them considerably more. I will try and feed one of the groups with something close to the manufacturer's recommendations.

 

[SmokingWings]

For my next batch I will divided the plants into two groups and start feeding them considerably more. I will try and feed one of the groups with something close to the manufacturer's recommendations.

Using large groups of plants to run tests is the best way.

 

[kirkandfamfarm]

hey did you test any of your plants for hop latent? i had the same problem back in february and tried over and over until we had the diagnostic of an infection going on

 

[bluter]

Yes, I grow in Plagron Lightmix which is technically peat not exactly dirt, but I assume it falls under soils.

if it's amended you treat it like a soil. if it's raw you treat it as hydro. you have to ph / feed accordingly.

there isn't a huge jump in ppm when growing in peat, but it may need more than dwc or rdwc. most grow charts take it in to account. hydro growers usually reduce the given schedule, peat and soil growers almost never have to increase it. make sure you check with your nute lines particular chart.

your pots are too small. those plants are exactly the size i would expect a 2.5 gal pot to support. you can get way bigger plants in those pots if you go to a shoot to root system later in flower. it literally becomes a full time job though. if you want bigger plants get into 5 gal. your plants will also look better later in flower, there isn't enough media to support them.

you're also a bit crowded. i often get larger yields with fewer plants simply due to space restrictions. cannabis hates being bottled up. fewer plants with a little training will produce bigger yields.

there are nute issues i see, but most could be smoothed out in a larger pot.

 

[plan500]

Not a complete fail after all. Those plants were extremely starved during the most important weeks 3, 4, 5 and most of 6 as I had misdiagnosed underfeeding with overfeeding. I started feeding heavily week 6 and giving them WC teas with every watering and they are now at the begining of week 9. I did some damage control and managed to save what seemed a complete fail. Most important of all is that I learned a lot with this mistake and have currenlty adjusted all environment, watering and feeding charts. Thanks again to @Emilya Green and all of you, who have been following and contributed to this thread.

 

[plan500]

Just wanted to share some good results, based mainly on all advices I got in this post some time ago. Once I fixes the watering method, plants started taking off and next was a complete revision of all other factors such as feeding, lighting and finally VPD, which I follow strictly.

Special thanks to @Emilya Green, who saved me from certain death at the time I first posted here.

 

[plan500]

There is one more mystery left for me to solve, hopefully with your help.

Right around week 4-5, there is a sudden darkening of the canopy that happens literally overnight. One day they are all light green and lime and the next they get dark and remain that way until then end. Results are fine, but I think this is not normal and there should be a way to keep them light green until the end.

Nitrogen is the main focus of my experiments, I have reduced it a lot, especially after I flip them, I have attempted to reduce it further even getting yellowing in lower leaves, however I can never seem to save them from darkening eventually. Sometimes beginning of week 6.

My main question is, could this effect be anything else than excess nitrogen? Does something else cause this darkening?
Also, is this perhaps normal? I know it is not strain related as I have tried various.

I do see some clawing and the smaller plants and those with weaker genetics definitely show nitrogen excess symptoms, at least that's my read.

This has been happening my 5-6 grows as this is a repetitive production cycle. All other factors the same, reducing Nitrogen has not shown great improvement. The following pair images are taken 1 to 2 days apart and see the difference.

Plants are visibly happy at all times, but something is off. @Emilya Green ?

 

[013]

Looking amazeballs over here and there’s nothing stunted about your colas!!!!

it’s great to see the follow up and you showing thanks to peeps that jumped in