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Sustainable Alternatives: They took the P out of the NPK

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twiggybuds
Moss Point, MS
(Zone 8b)

March 7, 2009
1:34 AM

Post #6231371

Phosphorus is an essential building block for every living cell. I have high hopes for an abundant garden this year and I can't believe this is happening. I wanted 2 sacks of fertilizer today and WM was the most convenient. In the past, they always had at least one kind of balanced fertilizer such as 10-10-10. All they had was 13-0-13. I read on the sack that they're concerned for the environment so they left it out. I'm still in shock.

There is no known substitute on the face of the earth. I called the only remaining seed & feed in the county and asked about buying phosphorus separately. "Out of stock. Check back on Tuesday." I was in such a flap that I forgot to ask about what she had that was "balanced".

Last year the price of phosphate rock went up by 700%. Since the product at WM won"t grow anything, I wonder why they are getting $14.95 for it. I guess if it actually had the right stuff it would cost $50. I posted about peak phosphorus last year and evidently the situation has the potential for devastating food prices. Here's an article about how the rest of the world is handling it.

http://www.cleantechblog.com/2009/01/peak-phosphorus-commence-urine-recyling.html

darius

darius
So.App.Mtns.
United States
(Zone 5b)

March 7, 2009
8:06 PM

Post #6234444

I use CalPhos, which is a soft rock phosphate. It is more bio-available in the soil than hard rock phosphate, although found in lesser amounts around the world. (Florida usually has a good supply.) In the phosphate article I wrote recently for DG, I think I mentioned the concerns about finite quantities of phosphate and the future of agriculture. If I didn't, I should have... although the DG policy for articles is not to use any scare tactics.

I'm due for a trip the first week of April to the organic supplier where I get most of my amendments... I need more CalPhos, greensand and azomite. I'm wondering if I should double my order of CalPhos? I won't stockpile it... not fair to other gardeners. Of course, all the phosphate in the world won't do much good without a healthy supply of microbes in the soil to break it down so plants can absorb it via their roots.
grownut
Clarkson, KY

March 8, 2009
3:36 AM

Post #6236238

I'm afraid my reaction was far too, erm, earthy...just goes to show the world needs a lot more p(ee). Local.
garden_mermaid
San Francisco Bay Ar, CA
(Zone 9b)

March 9, 2009
1:09 AM

Post #6240012

darius, if doubling your order saves in transportation costs, you may want to consider the ecological/economic benefit of that. A double order may be just basic thrift and time savings rather than stockpiling.

We found a number of garden amendments in short supply this year, presumably due to the increase in home vegetable gardening. Meanwhile our seedlings were still hoping to spread their roots in the open soil, with or without amendments. Kind of threw off my feeding schedule.

darius

darius
So.App.Mtns.
United States
(Zone 5b)

March 9, 2009
2:22 AM

Post #6240375

Good point. That supplier is about a 2-1/2 hour drive each way, if I remember correctly. A nearby DG friend may ride/shop with me, and I have a list from a 3rd DG friend.
dparsons01
Albuquerque, NM
(Zone 7b)

March 11, 2009
3:33 PM

Post #6251473

I take the approach of building the long-term supply of minerals in the soil. I use CalPhos like darius. Less fertilizer is needed then, if at all, depending on what you are growing. Another consideration is to add carbon to the soil (bio char). The carbon helps hold nutrients in place so they aren't lost as readily.

darius

darius
So.App.Mtns.
United States
(Zone 5b)

March 11, 2009
3:38 PM

Post #6251490

Good point, d... I add bio char too.
dparsons01
Albuquerque, NM
(Zone 7b)

March 11, 2009
3:53 PM

Post #6251562

On the subject of maximizing resources, I planted Clover around the Fruit trees I planted this Winter. I needed/wanted a ground cover and reasoned that the Nitrogen fixing associated with the Clover might benefit the Fruit trees as well even if I didn't turn under the Clover. I got a comment from another gardener that this does indeed work and found that this is done in some Orchards. There is so much Nitrogen in the air, and setting a system in place to make use of it makes wonderful sense.

darius

darius
So.App.Mtns.
United States
(Zone 5b)

March 11, 2009
4:00 PM

Post #6251606

Hmmmm, I'll have to consider that when I can finally buy some fruit trees. Thanks.
AlohaHoya
Keaau, HI
(Zone 11)

March 12, 2009
4:56 AM

Post #6254909

What about Molassas as an additive en lieu of the P in NPK?
Vashur
Wichita, KS
(Zone 6b)

March 18, 2009
6:59 PM

Post #6285911

I haven't had any trouble here getting garden fertilizer but the price is high. I finally went to a farm store and got a much better deal. They charged about 18 dollars for a 40 lb bag of 11-15-11.
David_Paul
Clinton, CT
(Zone 6b)

April 10, 2009
1:59 AM

Post #6389379

Vashkur...excellent price. I paid $23 for 40lbs of 10-10-10 and I had to drive inland to get it.

CT soil is notoriously low in P. Can't imagine the middle number being missing in my state. When I dug a garden out of the lawn the soil test showed 1lb of phosphorus per acre!

Three years into it, lots of organic fertilizer, lots of composted cow manure and the soil test came back this year still below optimum.

Crops are very good because I spot fertilize but decided to stop pussyfooting around and, last week, applied triple phosphate. From now on out, I should be able to do compost and manure.
twiggybuds
Moss Point, MS
(Zone 8b)

April 10, 2009
5:16 AM

Post #6390125

I took drastic measures. The 2 sacks missing the P are still in the garage unopened. I have 4 bags of triple phosphate (4lbs @ $7ea). No doubt we use too much P because so much of it ends up as pollution. I started researching and still don't know what I'm doing because there are wild variations in recommendations.

I read that micro-nutrients can make a big difference in how a plant uses P so I ordered some Mittleider Magic Micro Mix. It says to mix it with epsom salts and triple 13 for a COMPLETE fertilizer. Cricket's Greenhouse which posts on the market growers forum uses it and gets phenomenal results with 1 tsp per week per plant. I will play with the triple P to see how little I can get away with.

My native soil is useless and I grow in pots sitting in a plastic liner with constant water. I only lose nutrients when there's a prolonged rain or a gully washer. I may have to resort to a hydroponic type. This has been a learning experience. By the time you buy all the items in an ideal recipe, fertilizer is getting very expensive.

I bought a 50# sack of epsom salts for $35. That's a lot cheaper than the little bags from the drug store. I also got 50 lbs. triple 8 for $10.95 to get by until I figure out my recipe.
gloria125
Greensboro, AL

April 10, 2009
3:30 PM

Post #6391236

Here is an explanation for removing phosphorus from commercial fertilizers in Minnesota.

http://www.extension.umn.edu/distribution/horticulture/DG2923.html

Major sources of phosphorous are (1) compost (2) manure (3) grass clippings
in addition to bone and rock phosphates.

Before you add phosphates to your soil you should get a soil test. Chances are you are contributing to the problem of phosphate pollution!

I think dparsons post above is probably correct. You can use green manures to add phosphate to your soil. I havn't seen specifics pop up in the searches yet.

Yes. One solution was to have a discrete pot for collecting urine.


Now to just train Roscoe to go in the pot instead of ON the garlic (!)

darius

darius
So.App.Mtns.
United States
(Zone 5b)

April 10, 2009
3:43 PM

Post #6391297

Triple phosphates are very water-soluble, so be careful about using too much and causing run-off. Plants use a LOT of P, but any excess soluble P (like superten, triple superphosphates and DAP [di-ammonium phosphate] or their derivatives) becomes a problem.
garden_mermaid
San Francisco Bay Ar, CA
(Zone 9b)

April 10, 2009
7:20 PM

Post #6392143

You might want to consider using the slower release rock phosphates and then boost the microbial communities in your soil with something like EM or Bokashi to make this form of phosphate more available.
twiggybuds
Moss Point, MS
(Zone 8b)

April 11, 2009
5:41 AM

Post #6394444

Gloria I found that article very helpful. It reinforces the wisdom of compost and all other recycling of organic matter. Somehow I was unaware that plant residues were the major source of phosphate pollution.

I bought the triple phosphate because that's what the local seed & feed had available and expect it to last several years. No telling what prices will go to and I look at it as an investment in real security as opposed to paper securities. I'll be very careful with it.

I've been looking at various formulations and actually seeing low numbers for phosphorus. The water soluble fert for greenhouse vegetables is around a 1-2-4 ratio. It makes me wonder why the 8-8-8 and 10-10-10, etc., ever became commonly used in the first place. I've got to do some more reading.

gloria125
Greensboro, AL

April 11, 2009
12:50 PM

Post #6394917

twiggybuds: You really are a treasure for your ability to research and make us aware of what we are doing! Asking the right questions is half the battle.

sallyg

sallyg
Anne Arundel,, MD
(Zone 7b)

April 12, 2009
5:06 AM

Post #6398311

"tapla " , frequent poster on Indoor gardening, recommends a ratio of 3-1-2 in fertilizer. I think he said thats the ratio of those things in actual plant material, so it makes sense, and makes sense that compost has a good balance.

darius

darius
So.App.Mtns.
United States
(Zone 5b)

April 12, 2009
2:00 PM

Post #6399069

Ratio in the mix is only part of the equation; the other part is what's already IN your soil.

If the ratio needs to be a-b-c. then "a" (or "b", or "c") should be a combination of what's in the bag plus what's in your soil.

sallyg

sallyg
Anne Arundel,, MD
(Zone 7b)

April 12, 2009
7:01 PM

Post #6399998

must dig out my soil test, and really should get an updated one!

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