Superphosphate is sold as superphosphate. It is made by a reaction that takes place when rock phosphate is treated by sulphuric acid. Both are organic as far as I am concerned, but I don't know whether some standards board regards the end product as such or not.

Could you tell me if this is commonly sold in nurseries or those mega home improvements centers? Because I do not recall seeing any bags or boxes of superphosphate. Maybe I have to look closer. It's not something that would not be available in certain states, is it? I'm in So. CA.

I don't know how widely available it is nation wide, but where I live in SE Wisconsin it is easy to come by. There is a chain nursery called Steins in my area that has it, an independant nursery has it and I won't swear to it, but I think I have seen it at Walmart as well. Not sure about the chain hardware stores like Menards, Lowes, HomeDepot.

I would just call around, I would think somewhere near you would carry it. Start with those places you know to carry at least some natural/organic products.

If you are attempting to follow organic standards, superphosphate is not OMRI listed and is prohibited.

I am enclosing a link to a discussion of superphosphate and how it is viewed by organic standards boards.

Apparently there is at least one board that allows it's use under limited scenarios. There also appears to be a distinction made by some between superphosphate (allowed) and triple super phosphate (not allowed and viewed as a synthetic). The process to make each is different.

Anyway, to use it or not use it is completely up to you unless you want some board's certification in which case you have to play by their rules.

The link should provide you with some good knowledge to make your own decision.

Here is a link that might be useful: superphosphate

Superphosphate is not an acceptable organic product. Rock phosphate, the raw nutrient is acceptable, but should not be used unless a soil test indicates the need.

Not acceptable to whom, kimmsr? Any why is it not acceptable? What damage results from it's use or production?

During my lifetime superphosphate has never been recognized by anyone as an acceptable organic product. Sir Abert Howard wrote against its use as did J. I. and Robert Rodale. Many other organic garden wirtters over the past 50 or so years that I have been gardening organically have found superphosphate unaccetable to organic gardeners because of the acid bath used during its processing, that mkes the nutrient too readily available bypassing natures soil bacteria. Seems there was a study some years ago that showed that superphosphate, applied to soil, was harmful to the soil bacteria and earthworms, but mostly the objection is that the acid bath puts an unnecessary step in the processing of it. There is no reason to do that and that process adds major pollutants to our environment that we do not need.

I have decided not to use it. I was just trying to find a sub for bone meal, as it attracts my dogs. Thanks for all your info!

Here is a thought:

Since most soils that use sustainable methods of soil building (i.e. composting, green manuring, etc.), are normally high in insoluble phosphorus, try just releasing and making available what you already got!

I mix plain corn meal (which in rich in protein, sugars, calcium, and phosphorus), with dry molasses. The extra sugars and carbohydrates will greatly increase microbial action, which will release up more available P to your plants.

Diluted aerobic foliar tea applications can do that same through plant foliage.

Happy Gardening!

a duh answer, when I tried to use it, it killed my plants

Maybe if you apply a month before plant out at the correct rate and you have enough rain, It 'MIGHT" work for you

Just my 2¢

So is the consensus that superphosphate is simply too concentrated to use as a primary fertilizer?

It might be better used on areas a soil test identifies as significantly deficient in phosphorus prior to planting rather than as a feed for growing plants?

While browsing the organic and 'organic based' feeds at the local garden center I noticed that a particular product had all sorts of grains, meals and rock powders in it (good stuff), but it also had superphosphate.

It was only a 6-10-10 or thereabouts fert.

It appeared the SP was there for 'quick effect' phosphorus whereas the rock powder was there for more of a long term, slow release effect. As I recall the SP was the last ingredient listed meaning very little of it by weight.

Today I bought a 50 lb bag of triple phosphate 0-46-0 at a local garden center for $20.32 which includes tax. The price has gone way up within the last 10 years. A local county agent highly recommends triple phosphate 0-46-0& said that is all that is needed when planting. I have used triple phosphate 0-46-0 several years ago at a previous residence. I tilled the triple phosphate 'TP' into the soil when planting trees, shrub, perennials, bulbs with good results. But I didn't add any 0-46-0 to those plants afterwards. But at my new residence my concern is a fish pond downhill from my house/yard and I don't want any washing into it which may cause algae.
How much does a 50 pound bag of rock phosphate cost?
I am wondering if I need any phosphate at all since all the plants are growing wonderfully that I have planted at my new place. People comment that I have a beautiful yard. My fruits and vegetables have been outstanding. All that I added to the soil when I moved here was lots of compost and either hardwood or leaf mulch on top of the plants.
According to this link it makes me wonder how truthful soil samples results are, http://www.malcolmbeck.com/articles/phosphates-probemsandsolutions.htm
I did soil samples on the property soon after I bought it.
I am considering hauling the 50 lb bag of TP back to the store.
I am trying hard to establish earthworms. At my other residence it had an abundance of earthworms. I added granite dust which earthworms thrive on at the other residence. Granite dust is just ground up granite. It has lots of minerals and good for the soil.
Do you feel that the chemicals companies are lobbying our county workers? If so how can be stop this unfair practice? It is hurting our pockets books and the environment.

Superphosphate will kill off earthworms. Just a little too much superphosphate applied to the soil of growing plants will kill those plants. Superphosphate is a very soluble form of phosporus and is the source of much of the phosphorus pollution many lakes and ponds have that is causing the growth of toxic algae. Superphosphate is not something anyone would really want to add to their soil, even if a good, reliable soil test indicated the need for phosphorus. Less expensive is Rock Phosphate, the source of superphosphate, if a good, reliable soil test indicates a need for phosphorus.

toad08
"Do you feel that the chemicals companies are lobbying our county workers? If so how can be stop this unfair practice? It is hurting our pockets books and the environment."

It is possible that the chemical companies are swaying the extension service (though probably not so much at the county level.) Remember that the cooperative extension service is a system that was set up so that state universitys would share their agricultural research with farmers in their states. Most of my reading has shown far more information on "traditional farming" (traditional being that past 50 or so years of chemical dependence and soil depletion). The only times I see major information about less chemical methods is when the chemicals don't seem to be cost effective any more and the more organic methods show quick improvement. -they are slowly starting to catch on but the focus still is on large scale agriculture.- The extension service does support the idea of organic and some other good things but so far it really just seems to be lip service around here. Perhaps I haven't talked to the right agent but most of the ones I have talked to always make chemical recomendations, when I ask about organic alternatives the seem a little blank. Again, this is probably mainly because the systems is geared more for large scale agriculture and not home organic gardening. In my part of the state it seems that very few people bother with home veggie gardens anyway and the few organic ideas the extension service has for home scale use has more to do with ornamental and lawn care (use a mulching mower and spread your leaves under your shrubs so the county doesn't have to pick up as much yard waste) and that sort of thing.

Super phosphate is an excellent concentrated source of phosphorus, but it is by no stretch of the imagination 'organic.' When you think of the opposite of an organic phosphorus fertilizer, youÂre thinking of super phosphate. It starts as rock phosphate, but goes through a chemical plant where the P is concentrated with acid. The general organic philosophy about fertilizer ingredients is that they be something that occurs naturally and is either mined or are animal or plant byproducts. Something that comes strait out of a chemical plant is frowned upon.

Thought this might help clear up...

Click on the link..

Here is a link that might be useful: The Hidden Truth About Commercial Phosphate Fertilizers.

Lou the link returns a blank page, nothing. This morning everything about Mr. Beck comes up blank.

Strange. It was working yesterday. I wonder if their server is down. I thought that article was very interesting (and all the articles Mr. Beck wrote).

Now the link is working...

I will be planting onions soon which require a vertilizer rich in phosphorus (10-20-10) to be banded in the soil before planting. What would be a good organic alternative for this purpose?

You will not find any organic source of phosphorus with numbers that high, but Rock Phosphate and organic matter are both good sources of phosphorus, over time. The best time to correct any soil nutrient deficiencies is about 6 months before they will be needed.

I've been planting lots of onions and never done anything extra for them for phosphorus. Then again the soil here is either naturally high in phosphorus or the previous owner over did things in that department.

Anyway, The common organic high phosphorus choices include rock phosphate which is mined and bone meal which comes from the meat industry. More balanced organic things to add to your soil include aged/composted manure, compost, and leaves.

If you feel you must band with some sort of fertilizer then you can probably go spend lots of $$ and get some of the fancy formulated organic fertilizers from the store though they probably won't have the numbers you are asking for. This usually just means that you have to use more to get those numbers but unless you have had soil tests indicating you really need that, most people here won't really support the idea.

Another thing to consider is that phosphorus is less available in acid soils. Raising the pH by liming or increasing soil organic matter helps with that.

If you garden in acid clay soils as I do now, the low available P will be very evident in root crops like onions. However, adding 10-20-10 is not necessary to raise P - I'm using a combination of bone meal, rock phosphate, lime, and compost.

My father's garden (before he moved into assisted living) was formed from 20 years of adding sifted compost. It was like chocolate cake and his onions were enormous. My sister and I seriously considered hiring a truck to move his compost pile...

I was looking for triple superphosphate to plant asparagus. I guess I will look up organic methods. Is superphosphate ok?

The Ohio State U Ext says "Apply about 1 lb. of 0-46-0 (triple superphosphate) or 2 lbs. of 0-20-0 (superphosphate) fertilizer per 50 feet of row in the bottom of the furrow before planting. This will make phosphorus immediately available to the crowns. Omitting this procedure will result in decreased yields and the spear production will not be as vigorous. Toss the crowns into the furrow on top of the fertilizer. The fertilizer will not burn the crowns" so it sounded pretty safe to me!

I put several tablespoonfuls of superphosphate in all my planting holes and all my plants are doing wonderfully.
Don't know why you guys say rock phosephate is OK, but the same stuff treated with acid to make it more concentrated and more readily available if bad. Did you ever consider the cost of transporting the stuff, when you need several times as much rock phosphate to equal the amount of nutrients in an equal weight of superphosphate?

Because gardenweb is a great source of info for new and novice gardeners, I feel the need to counter the chicken littles.

I am an organic gardener and I would never use superphosphate or triple superphosphate in my garden.

My neighbor is not an organic gardener, is an AG professor at NC State and is a fan of triple superphosphate. If directions are followed, it is not too strong and it will not kill your plants. He does have amazing yields of fruits and vegetables and his flower gardens are unrivaled. Is this because of the TSP or because he spends hours in his garden every day - weeding, watching, nurturing - who knows...

Superphosphate, because it is processed beyond necesary, is not an acceptable organic material. OMRI does not allow its use on a certified organic farm.
Now comes the question does one really need this material?
My soil has gone from low levels of P to "High Optimal" over the years simply by adding adequate levels of organic matter, compost, shredded elaves, yard and kitchen waste to that soil, no rock dusts, no mineral amendments of any kind.
Sir Albert Howard wrote that soil health could be achieved by making compost and adding organic matter to the soil, and proved that it would. Lady Eve Balfour and Friend Sykes found that following Sir ALberts recommendations their farms soils improved in health. Most everything I have seen about the need to add these "fertilizers" to soils comse from people with a vested interest in selling us a product.

I like the idea of using molasses and corn meal. I'm afraid it would attract the dreaded fire ants though. Anyone know if it would? I have an outdated bottle I like to use somehow.

Bacillus Megaterium is one of the largest and most important microbe in soils & organic gardening. It not only fixes usable nitrogen directly to plant roots, and protects plants crom a #of diseases, but it hydrolyzes organic phosphorus from bone meal, rock phosphate, and other sources; Basically it breaks it down and makes it available to the plants. Triple superphosphate not only suppresses this and other microbes, but over time will build up harsh insoluble compounds in your soil.