Commercial fertilizers are sold with the major nutrients listed as a percentage of total weight so a bag of 5-5-5 fertilizer that would feed 5,000 square feet would have 2.5 pounds each of Nitrogen, Phosphorus, and Potash. Your counties Cooperative Extension Service horticultural agent may be of help here.

The only one off the shelf that I can think of that is close to your needs is ammonium phosphate. That is 16-20-0-13S. This is usually used to root new sod. You don't say whether you need sulfur so the 13% sulfur may not be what you want.

You could add bone meal (3-15-0.5) to get to your needs.

Here is a link that might be useful: Ammonium Phosphate

If I read your post right, it sounds like you need phosphorus and some nitrogen. In the usual garden/hardware place it would be hard to find something like 10-20-2. At worst you may have to use 10-10-10 with a nice addition of bone meal.

What does 03 lb of K2O mean? Is there a typo in that value? Looking at your ppm values it seems you need way more K than the others, rather than zero. Please clarify for us.

Here are the simplified numbers

N - 3 PPM (recommended 1.3 lbs per 1000 sft)
P - 10 PPM ( recommended 3.1 lbs per 1000 sft)
K - 143 PPM (recommended 0.7 lbs per 1000 sft)

I ran the above numbers through a basic fertilizer calculator and got a recommended fertilizer with values 1.9 - 4.4 - 1. I am wondering if there is anything I can do to get close to the recommendation by either mixing or adding more than one fertilizer.

I'm starting to think your ppm numbers are the test results, followed by recommendations? If so it makes more sense now.

Nitrogen is the most changeable with seasons, temperature, etc. so it's not critical to get that one spot on.

I would look for something with a higher middle number and call it good. 5-10-5 should be available, or something similar. As mentioned above you could add some bone meal to boost the middle number.

Hopefully, you are composting and/or adding compost to your soil? It's important to maintain organic matter levels, and it will add not only some NPK, but many micronutrients, plus ion exchange capacity which makes them more available to plants. Precision fertilizing becomes less important when you have all that going.

Why worry about N? next year it will be a different ball game. So just put down chicken manure, one inch. It is the best high P organic amendment. That will not get you to the exact ratio but stuff will grow well this year. Next year, I would go with another inch of chicken manure. Following that, just mulch and urea.

Thanks for all the suggestions. Yes I am using compost and a lot of it as the soil is clay.

I put compost on my clay for 15 years and ended up with pretty high P and K, which I found out with a soil test. P especially will stick around and not leach away quickly, so once you get some in there it'll be fine with just compost additions.

Thank you, toxcrusadr, for that uplifting info. My soil is alkaline clay with pH 7.7 where P is tied up with my high magnesium and calcium dolomitic clay. I raised my K, or potassium level with horse manure, but my P, or phosphorus is still tied up.... need compost here!

Hi ssistla: I would take the the soil test recommendation of adding Nitrogen moderately. You have clay soil, and clay retains nitrogen very well. I have limestone clay, with 26 trees .. I NEVER fertilize my deciduous trees, and they are taller than 2-story house, lush and green.

Air is made of 78.09% nitrogen. Nitrogen is also in rain water. I can see adding nitrogen if your soil is sandy, or if you grow stuff in pots, where nitrogen leaches out with water. According to Robert Morris NOBLE plant foundation, nitrogen is extremely mobile, a 10, it moves with water. Potassium is somewhat mobile, a 3. And Phosphorus, is a 1, it stays put where applied. Toxcrusadr is correct, as always!

Clay retains nitrogen extremely well. That's why EarthCo., the soil-testing company DID NOT test my nitrogen level, they tested my organic matter (good here). Their booklet stated that 10% of organic matter is enough to supply nitrogen.

If you have sandy soil where nitrogen leaches out, it will contaminate ground water. The other disadvantage of nitrogen is you'll get less fruit and less flower. Here's a remark from Michigan State University botanist: "It's the ABSENCE of nitrogen fertilizer that promotes flowering, rather than the use of phosphorus fertilizer."

Here's a quote from David Neal, CEO of Dyna-Grow Plant Nutrition in CA: "There is some evidence to believe that low N helps to convince a plant to stop its vegetative growth and move into its reproductive phase (flowering), ....There is little scientific justification for higher P formulas, but marketing does come into play ...."

Nitrogen movement is a 10, potassium is a 3, and phosphorus is a 1, most stay-put. Nitrogen moves with water and is most leached out. Organics is the most-slow-released, so leaching would be least.

A better measure of nitrogen requirement is how much of it is lost, rather than how much is supplied. From the plant deficiency chart, from pH of 5.5 to pH 8.5: there are plenty of nitrogen in the soil. Only when it's more acidic than 5.5, or more alkaline than 8.5, that nitrogen is tied up.

My soil test told me to fix my alkaline clay with sulfur, it didn't work: clay requires more sulfur to fix than sandy soil, sulfur killed earthworms, and I actually get less blooms.

I googled "photosynthesis" and found this quote "Since plants get carbon, hydrogen, and oxygen from the air and water, there is little farmers and gardeners can do to control how much of these nutrients a plant can use."

The salt index of chemical nitrogen fertilizer is highest, between 70 to 80%, it's like dumping salt on your land.

When I googled "excess nitrogen fertilizer", it's very depressive "ground water contamination, salt damage, shallow root, more watering, deformed blooms and fruits, and less drought-tolerant, less winter-hardiness, more diseases and more pests and insects."

When I googled "nitrogen deficiency" ... it's not bad, just chlorosis, or pale leaves. I have roses that way in pots since nitrogen leaches out ... at least they healthy and loaded with blooms. When I put them in my clay soil, and give them high nitrogen fertillizer to green them up, they refuse to bloom.

Never underestimate the slow-release power of organic fertilizer, the NPK value of blood meal is 12-0-0, but the staying power is many months. Same with alfalfa. I threw blood meal on marigolds and it was over 3 feet tall, zero flowers for the entire summer.

My translation: Don't give plants what you think they need, or what another person dictates, give them what they actually cry out for.

Below is a picture of a rose fed in NPK ratio of 2-1-2 (alfalfa meal). Is that what you want? Lots of top growth, shallow root, and no fruits nor flowers?

Here is a link that might be useful: Salt index of chemical fertilizer, highest in nitrogen

Below is a picture of my rose Evelyn, only 1 month old, own-root/gallon-size. I fed it with lots of alfalfa meal NPK 2-1-2, or twice higher in nitrogen. My clay soil high in magnesium and calcium also bind with phosphorus, making less blooms when too much nitrogen is applied.

All true, but it's important to keep in mind there is a lot of space between nitrogen deficiency and nitrogen excess, and that's where nice healthy growth occurs. I have not seen a soil test posted yet that did NOT recommend adding N, and you have to wonder if it's really so necessary to do so, especially (as Strawberry says) in soils with plenty of OM.

Since air is composed of 78.09% nitrogen, and 21% oxygen ... check out this process called "natural nitrogen" fixation in plants:

"Natural Nitrogen Fixation via Microorganisms

Nitrogen-fixing bacteria and algae use nitrogen gas to make ammonium compounds. These compounds are absorbed by plants.

Two main groups of microorganisms carry out nitrogen fixation. The more common of the two groups is made up of organisms living in soil and water��"a few species of bacteria (chiefly of the genera Azotobacter and Clostridium) and some blue-green algae.

The second group, consisting of bacteria of the genus Rhizobium, lives in plants, primarily legumes such as peas, clover, and alfalfa. The bacteria cause the roots of legumes to form root nodules (swellings) in which the organisms live.

The plants supply the bacteria with food. In return, the bacteria secrete ammonium compounds that are absorbed and used by the legumes and by other plants that are grown in the same soil.

Lightning plays a minor part in the fixation of atmospheric nitrogen. The extreme heat of a lightning flash causes nitrogen to combine with oxygen of the air to form nitrogen oxides. The oxides combine with moisture in the air. The fixed nitrogen is carried by rain to the earth, where, in the form of nitrates, it is used by plants."

From Straw: nature fixes nitrogen for us. Do we really need to dump chemicals high in salt to pollute ground water?

"High in salt" is a bizarre statement. No one is going to get too much salt in their garden soil by adding a few handfuls of 5-10-5 granulated fertilizer to their plot. People have been doing so for generations without harm.

Plants pull nitrogen from the soil as they grow. When you harvest them and pull up the stalks, you remove the nitrogen from the field. If you don't replace the nitrogen somehow, later plantings will suffer. it's very simple - you can't get something from nothing.

Nitrogen can be generated by legumes on their root nodules. But many crops are not legumes. Even then the nitrogen generated must be utilized in a timely manner or some will disappear. Lightning does add a small amount, bur the key word is small.

Actually, the soil solution (microscopic layer of water on the surface of soil particles) as well as the ion exchange sites on the surface are full of what would also be described as salts. That is, ions of all sorts. K, Na, Mg, Ca, chloride, nitrate, phosphate, carbonate, bicarbonate, and on and on.

That said, I think many if not most of us lean toward minimizing the use of fertilizers (in favor of compost). Small amounts of fertilizer applied to the garden in response to a soil test is not irresponsible - quite the contrary - and will not pollute groundwater in the vast majority of cases. In clay especially, leaching is very slow.

And there is no doubt that yield can be improved by fertilizers. It should be done with common sense and soil health needs to be preserved, but as long as those things are done, if it's needed, use it. Just my two cents.

I researched on the salt content of fertilizers: plant-organics like alfalfa, leaves, and grass clippings have no salt. Next lower in salt is blood meal, NPK 12-0-0, last are animal manure and chemical fertilizers, especially nitrogen are highest in salt.

The advantage of organic sources of nitrogen are: 1) none or low-salt 2) slow-released so nitrogen won't be leached out. 3) salt doesn't matter much in sandy soil, but can accumulate in heavy clay.

See the link below for the salt content. This is the second site, besides the first site from University of Illinois, that I posted earlier.

Here is a link that might be useful: Fertilizer salt index

•Posted by jonfrum 6 (My Page) on
Tue, Mar 5, 13 at 18:51

"High in salt" is a bizarre statement. No one is going to get too much salt in their garden soil by adding a few handfuls of 5-10-5 granulated fertilizer to their plot. People have been doing so for generations without harm.

Jon,

Every post you post I agree with 100% Do you own a farm?

I think people conflate salt as in table salt and the whole "Romans salting the fields of Carthage" thing with a scientific concept of metal salts. Table salt is bad because of sodium and to a lesser extent chloride toxicity. However, careful applications of other metal salts are not going to cause those problems. You're not going to get any sodium or chloride toxicity from ferrous sulfate. Generalizing about "salt" is probably a bad idea.

"No one is going to get too much salt in their garden soil by adding a few handfuls of 5-10-5 granulated fertilizer to their plot. People have been doing so for generations without harm."

Jon, while yours is not a bizarre statement, it is imprecise and totally unverifiable. What is know for sure, based on lots of evidence, is that chronic use of fertilizers with a high salt index, whether natural or synthesized (if you search "fertilizer salt index" the whole issue may seem less bizarre to you) in conjunction with heavy cropping results in greatly reduced soil fauna.

With regards to the salt index, the osmotic problems can be solved by decreasing the concentration of the solution. The problem is the application of large amounts of fertilizer salts at once leading to fertilizer burn where water flows from an area of high concentration (roots or the cells of bacteria) to an area of low concentration (high TDS soil). If small amounts of the fertilizer are added more frequently those problems can be avoided.

I think a large number of people misunderstand the term "salt" as used in chemistry.

Here is a link that might be useful: about salt

Generally, though, gardeners want to add fertilizer once and be done with it. Like this thread, where there is an idea that one application of a salt fertilizer will balance an imbalanced soil.