Renew depleted soil Phosphorus

My soil ran out of Phosphorus before harvest and I got really wimpy buds. Potassium got used up too, but I can take care of that with bone meal and bat guano. But the phosphorous is another thing. I normally use Texas greensand for it but it takes about 3 or 4 crops before that stuff breakers down into nutes the plants can use. So, how can I get the K. up for my next grow in a couple of weeks?


Use a Soluble version…The quickest way to get K into a plant
Otherwise it takes much longer for it to be absorbed
If you boil ORANGE PEEL and let is steep for 4/5 days in a dark place, you will get HIGH K and P too


@OldStoner bone meal or soft rock phosphate. I use a mixture of both myself if my soil runs out of phosphorus. Bone meal for immediate use and soft rock phosphate for “slow release.”

You can find both at most shops and nurseries that sell dry amendments but if your local shops are out has a great selection and they are one of my preferred online retailers for amendments.

Another good one to check out is the earth juice Verde Fire grow and bloom. They are great organic dry amendments. They can be top dressed, you can make a tea, or you can mix with water and feed. Earth Juice is one of my favorite brands to use when I don’t have the time or space to build my own soil.

Happy growing man.


@OldStoner also, welcome to the forum.

Quick note about my previous response, be careful if you choose to amend with both bone meal and rock phosphate. Bone meal acts immediately but rock phosphate only immediately releases approximately 2% of the phosphorous immediately. Both together can over saturate your soil with phosphorous if not mixed properly so amend accordingly.

The rest of the soft rock phosphate is released into the soil over the next 3 to 5 years. :v:


I assumed you meant get P up. K is potassium. Are you trying to increase phosphorous or potassium?

1 Like

Potassium. Indonesian bat guano and bone meal both raise phosphate. What I need is a quick way to get enough K in my soil. Greensand is good but really slow. I need it now!
I read that soaking wood ashes will leach out K. That is why it is commonly called “potash”. Can anyone tell me more about this process?

@OldStoner organic langbeinite is good for potassium.

Wood ash or pot ash works too as a top dress but when I use it I mix it with dry molasses to get the ph right. Molasses adds a decent boost to potassium as well.

@OldStoner also, that soaking method is just making a tea using wood ash or pot ash. You aerate and soak it in a bucket with water. I add molasses as well. Let it set and aerate for 24 hours minimum. I usually go 48. Then starin and feed.