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Purple Gnarly Growth that Leads to Death

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Let's think about this for a moment... you stated you've had a good amount of rainfall this season and I see that your NPK is approximately 19-19-39 with the plants being in the pre-flower stage.

        That said, I'm going to suggest that you have a phosphorus deficiency... here's why. 

When plants are in pre-flower they need and use a considerable amount of phosphorus (P). Phosphorus should be the highest number in your NPK during this stage. Phosphorus is responsible for stimulating bud sites, enhancing & encouraging bud development/set and flowering...  it's also needed in abundance if you're making seeds, as the plant will use up its P reserves for seed formation. If P is not found in high enough amounts, it could result in a stressed plant that may abort its developing seeds before they're finished.


So, back to the problem at hand. Excessive rainfall can leach phosphorus out of the medium/soil and create a phosphorus deficiency in the plant. Mix this with cooler root zone temps and you have a serious problem.    Root temps that are too cold cannot uptake phosphorus or much else, for that matter. This is true whether it's in a container or growing in the ground and "too cold" may be in the 60°F range or lower, depending on genetics and other factors. Do what you can to keep your plants roots from getting too wet and too cold... aim for above 74°F.     Ambient heating mats under containers for indoors and a thick layer of mulch over the entire root zone for outdoors.

Phosphorus is found abundantly in natural soils, but it cannot be utilized by plants unless it is in water soluble form. Since P is an active acid mineral with a strong negative charge, it will attach itself to the nearest positive charge, which is normally calcium (Ca). Combine Ca and P together and you have calcium phosphate, a very hard, stable, yet non water soluble compound. (Our bones are made from calcium phosphate.) Use mycorrhizae fungi in your grow medium/soil to break down these compounds and make these nutrients available to your plants again.



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gallery_2193_1497_631443.jpggallery_2193_1497_1047102.jpggallery_2193_1497_381247.jpgDesertGrown is dead on. Fought phosphorus lock out for years on outside grows. No mater what I used to grow in, it would come every year.  5 gallon buckets outside with the same dirt mix and no problem. I believe it was caused my a certain type of tree that grows here. 



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Yeah that was some good info and something for me to remember. I had a feeling I would be dealing with something along those lines when I got the two outdoor plants that are in the ground growing good. I never got to let any plants get so big in the past because of somebody seeing them. But with a 7 foot tall plant I expected it would be taxed as hell and it seems to have paid off. I actually sort of overloaded to what I would normally have done and really glad I did. 

I did notice they seem to stall out a little last week and fed them hard PK again and now they look normal with the buds swelling and the seeds looking more mature already. 

Thanks Desert!!



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Certain trees, and insect interaction are a source of Phytoplasmas.:tu


We use Calcium Nitrate.


15.5-0-0, and is a  highly Bioavailable source of Calcium, and Nitrogen.


Base formula is 4-19-39


We mix these 2 together along with Magnesium, and MPK when the time comes at 1st bud set.


In early flowering, we hit them with MPK

0-52-34, but they start turning purple long before they need that. A month anyway.


Im/we using the formula Chem Gro recommends for  These are in Promix BX, which is Sphagnum Moss, and is technically Passive Hydro. They also have AZOMITE, and KELP.


We also use the same stuff indoors and no problems, for the last 2 years, and have been growing weed inside since the invention of HID for weed in the late 70s. 78 I believe. Ive used Miracle Grow 20-20-20 with magnesium plenty of times successfully. Not saying its the best, but it can work.

Ive never had this problem in 45 years, regardless of fertilizer.


On an 8 weeks flowering strain we give them MPK for 2 weeks. 2nd, and 3rd weeks, with increasing amounts of Magnesium, and everything else until the 5-6 weeks, and then the food is cut back, but not a lot. 


Chem Gro has been making plant specific fertilizer since 1965, and came up with a weed specific formula, and use tissue analysis as their basis of the formula. I believe Jacks is all but the same formula ratios.



But its no fertilizer deficiency, or PH. PH is 6.2-6.5


Weed also need Nitrogen all the way through the grow, and is a myth to starve them of nitrogen.


All nitrogen is is protein.


Humans eat Protein and out bodies turn it into Nitrogen, and plants bypass this step, and take in straight nitrogen.

Its like limiting Protein and youre lifting weights, and trying to get Bigger, and stronger. When things are growing, they need more Protein.


So Protein being 1 of the basinc elements to build cell structure, is not logical to limit it at any time.


The thing is, is not over do it. Many propogated this myth because they gave the plants to much nitrogen, and can cause more leaf, anf delay, or stop flowering, but mistakenly started propagating this myth almost as long as I can remember. At least in the early 80s.


We used to blast them with 5-50-17 back then. But theres no legit studies Ive read about that says its advisable to limit nitrogen. They do say to boost MPK when buds first start to set, and at the full dose of magnesium when the are fully set, and to slightly/incrementally increase the base formula at the same time until the last 2 weels of flowering, and then the last 2 weeks, only Slightly lower it, as you shouldn't need to flush, if youre not overfertilizing them.

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