Slow release Potassium?

Potassium sulfate is organic whether OMRI wants to admit it or not.

 

The curious thing is, some organic coco growers say they have a problem late in grow of coco accumulating too much K.

 

Greensand is a good slow release of K and works very well with kelp I add it to a fresh mix and it's good for a couple of years. I don't top dress with it or anything.

Besides the initial mix, I top dress kelp meal several times throughout the season.

Granite meal is another slow K source. Most of the 'straight' organic sites mention it as a K source rather than a rock dust/mineral source. I first heard of this from an organic garlic grower who recc a side dress of granite meal as soon as you could work the ground in Feb or March. This was about 8 years ago.

HTH

 

whats your soil recipe?
most folk around here use the recipe in the no-till thread and it seems to contain everything that is needed.
have you observed actual deficiency in your container plants?

btw, OMRI is just a label.

 

concerning salt, you can check out gypsum and see if that in anyway fits into your program. It is sometimes used as a flush for salt, but as far as I know, the ph affects of it's longterm use in container or even outdoor soil is unknown and probably soil/grow specific. Tomato tone uses gypsum, and also has plenty of K from potash I think it is. I use tomato tone all the time and have for a long time. And I use a lot of it compared to what is recommended. http://www.espoma.com/wp-content/uploads/2015/03/Esp_Tomato.pdf

 

Curious what your objection to a "salt" is. In chemistry terms "salt" does not infer it's as sodium or sodium chloride (table salt), rather, it simply means a substance is in it's ionic form AKA 'water soluble'. Salt to a chemist is different than salt to a budding organic gardener. Same as 'organic' is different to a chemist than it is to the USDA NOP (supersedes OMRI).

How do we know we won't run short on K during growth? We don't "know" but we attempt educated guessing by understanding that K is taken up almost on par with N during all stages of growth, and by guessing we add copious amounts of kelp and compost and EWC, and maybe a few of the others already mentioned such as greensand and potassium sulfate (perhaps). Manure based composts will typically have lots of urine mixed in with it. Potassium is easily excreted in the urine of animals and humans. So, if the animal manure is resulting from a diet sufficient in K then K will be in the urine.

Depending on the amount of and type of any clay materials in your soil will directly impact an accurate reading for K in a soil test. It's a somewhat long explanation but in short, certain clays are as silicate in that there are layers comprising the whole. K in it's ionic form (cation) is drawn into the clay layers (anion) whereby the layer collapses and the K is trapped. pH is also a consideration for your soil test. If you're using the 'color' method of testing your soil, good luck. Those soil tests kits are rickety to say the least and very misleading to say the worst.

How does the 300 acre organic farm ensure adequate amounts of K? Langbedite (Sul-Po-Mag) is a natural source of K, Mg, and S, and is great for open field agriculture but it's not ideally suited for container gardening. I recommend NOT using Sul-Po-Mag in your container mix but OMMV.

If you're making your own compost ensure lot's of vegetables known to be high in potassium are included such as cucumber skins, banana peels, leafy vegetables. There are plenty of analysis documents available showing mineral content of harvested veggies. The old skool way of being 100% 'organic' making your own K is by the reducing to ash the skins of cucumber. A dutch oven or an iron skillet on an open fire works best.

So that's my cut. We don't really know-know but we make educated guesses. At least I don't know-know.....

 

I run a lot of banana peels through my worm farm and top dress with that along with adding 1/4 cup of greensand per cubic foot in my soil mix.

Sent from my LGMS395 using Tapatalk

 

I actually feed my worms Tomato-tone. Along with kelp,neem,alfalfa,crab meal. By the time they get done with it that pretty much covers everything.

 

Heres a thought for ya (and I'd like the more seasoned and expetienced organic no till gents to correct me if im wrong or share their experience in this matter)
I havent tried this myself but i read it somewhere online and plan on trying it soon!
Mung beans, brother!!! Sprout them (as you'd sprout barley or any other grain for the enzymes) n grind then top dress as you would malted barley. Enzymes and added K.

Happy growing brother

Check out my current Organic Fruit Garden:
The Doc's 2Strain Trial Organic Run: Tangerine Dream & Pineapple Chunk.
and my previous QuadStrain grow :
Thr Doc's 4 strain MMJ garden: CBD Critical Cure and more ;-)
and my previous TriStain grow :
The Docs TriStrain adventure: (White Widow, Bubblelicious and Amnesia) Waterfarmed and SCROGed

 

@ Pot.atoFarmer, have you tried any hardwood ash, I think it meets your requirements/preferences.

Sent from my SM-J700T using Tapatalk

 

I don't believe it takes (anywhere near) as much of any nutrient, including Potassium) as folks tend to think it does, and especially in a living organic garden to grow vigorous healthy plants - and being able to grow a dozen; more even, large healthy cannabis plants in the same pots of soil proves it IMO.

J

 

Consider these test don't show anything at hasn't broken down yet, there's probably plenty of K it's just in slow release.
If your plants don't look deficient I'd say you don't have a problem.

 

I assume you're minimizing water usage, which is why you're concerned about salts and salt build-up? If you don't water deeply enough with adequate drainage, salt build-up can be a problem with any amendment besides green manure/cover crops.

Well-composted stable bedding that starts out at wood chips/pellets and horse manure & urine has lots of phosphorus and potassium and works as a slow release fert. People who use it as their sole amendment can end up having excesses if they don't water enough.

I add 4 inches of composted stable bedding on top of the soil. Works well, improves tilth, never had a shortage of K or P. I water it in well.

 

I'm curious what a soil test on some of your soil that you would consider well used would show.