Home soil tests don't work and are a waste of money.

An actual soil analysis is SO worth the money. My local garden center has home tests for $10 and will do a soil analysis for $14. The soil analysis is 10 times more in depth and 100 times more accurate. On top of that, the analysis they do comes with access to a website where you can enter in what you want to grow and it will show you what you need to amend the soil for that crop based on your analysis. Not bad for 4 more bucks.

Ditto! Hey Retiredprof, check out the thread below to the U of Delaware's soil sample submission form complete w/instructions for submitting a sample, phone numbers and addresses.

Here is a link that might be useful: SOIL SAMPLE FORM

Those home soil test kits are very unreliable, and do not really tell you why the get the results the often do. Is you P indicating low because the soil pH is not where it should be? Is the soil pH real of not, because that depends on just how good that test material is and often it is not good. Contact youe local office of the University of Deleware USDA Cooperative Extension Service and inquire of them about having a good, reliable soil test done, adn you will get back a good report that tells you the whys as well as the whats. Then dig in with these simple soil tests to see what your soil is really like,

1. Structure. From that soil sample put enough of the rest to make a 4 inch level in a clear 1 quart jar, with a tight fitting lid. Fill that jar with water and replace the lid, tightly. Shake the jar vigorously and then let it stand for 24 hours. Your soil will settle out according to soil particle size and weight. A good loam will have about 1-3/4 inch (about 45%) of sand on the bottom. about 1 inch (about 25%) of silt next, about 1 inch (25%) of clay above that, and about 1/4 inch (about 5%) of organic matter on the top.

2) Drainage. Dig a hole 1 foot square and 1 foot deep and fill that with water. After that water drains away refill the hole with more water and time how long it takes that to drain away. Anything less than 2 hours and your soil drains too quickly and needs more organic matter to slow that drainage down. Anything over 6 hours and the soil drains too slowly and needs lots of organic matter to speed it up.

3) Tilth. Take a handful of your slightly damp soil and squeeze it tightly. When the pressure is released the soil should hold together in that clump, but when poked with a finger that clump should fall apart.

4) Smell. What does your soil smell like? A pleasant, rich earthy odor? Putrid, offensive, repugnant odor? The more organic matter in your soil the more active the soil bacteria will be and the nicer you soil will smell.

5) Life. How many earthworms per shovel full were there? 5 or more indicates a pretty healthy soil. Fewer than 5, according to the Natural Resources Conservation Service, indicates a soil that is not healthy.

Here is a link that might be useful: UDel CES

I go further than these folks. I think university soil tests are unreliable and a waste of money. Any lab that uses hydrochloric acid to dissolve the soil first is wasting your money. Plants do not produce hydrochloric acid so the results you get do not correlate to what the plants can absorb. Plants give off carbon dioxide which becomes carbonic acid in the soil. That weak acid can only break the weakest bonds in the soil. Those are the minerals that are actually available to the plants. A proper soil test will use carbonic acid.

Here is a link that might be useful: Texas Plant and Soil Lab

I go even further. I say there isn't a reliable soil test on Earth. I take all my soil to a super secret lab on the backside of the moon.

University lab results work fine. Labs use many different types of extraction methods. The results given never claim that every bit of every element extracted is immediately available to plants. The extractable amounts of nutrients are compared to mountains of data correlating the levels of those nutrients to plant response.

For example, they aren't saying that being able to extract 35 ppm phosphorus in a sandy loam means that 35 ppm of phosphorus is necessarily available to the plant. It means that if you can extract that much phosphorus with that method (which may or may not include hydrochloric acid) it has been shown over and over again that enough of that phosphorus will be in a form that is available to plants to satisfy plant nutritional requirements for that nutrient. (Or can reasonably be expected to become available in time for the plant to use it through a multitude of processes)

Gargwarb: You use that lab too? Sorry the secret is out. Having done an enormous amount of vegetable crop nutrition research at the University of Florida on watermelon, pepper, sweetcorn, eggplant, onion, squash cantaloupe and several other vegetable crops, I agree with you. Some land grant universities do a better job than others keeping their research up to date, some use information from other universities in nearby states which may or may not be particularly good for a given location due to soils, climate, etc..

With respect to his comment about university soil test results being unreliable and waste of money, I find DChall's comment personally and professionally insulting, for the sake of civility I'll leave it at that. DC, I genuinely urge you to speak with any of the leading university soil scientists (with expertise in the area) in your state about how soil testing is correlated to crop response.

Michael

I genuinely urge you to speak with any of the leading university soil scientists (with expertise in the area) in your state about how soil testing is correlated to crop response.

If you can find the people Michael is talking about, then talk to the people at The Texas Plant and Soil Lab about how their tests are correlated so you have something to compare with. Show me a lab that has created a fertilizer schedule to produce watermelons all year long, created a fertilizer schedule to convert semi-annual pecan crops into annual crops, created a fertilizer schedule to remediate sodium sterilized soil, or show me anything similar from a university lab; and I'll take back the statement Michael found insulting. If he's in the biz then he can probably find what I'm asking for. Rather than getting pissed, show me where I'm wrong. I used to believe in university tests but someone showed me that I was wrong. If you can turn me back, that's great.

The Ag schools in every state have been testing soils in those states for many years and have that data available for your use, if you wish. The soil science labs are comparing the results of the tests they do this year with those done for many years, however most of these soil scientists are still hung up on Justus Von Leibigs erroneous assumptions about plant nutrition so interpreting the results you have may be a bit tricky. The soil test is one tool in making a good, healthy soil. That soil test is not the total sum of the knowledge necessary to make your soil into a good, healthy soil which is why you need not test your soil every year, or as some people do every month.

DC: Insulted yes, pissed, no. Could you explain a little further about the year-round watermelon example, not sure what you're driving at with that one. Pecans, way out of my area. On the "sodium sterilized soils" do you mean saline, sodic or saline-sodic soils?

I took a look at the lab's web site in your link. Aside from their CO2 based extractions, their methods look like pretty common fair, I.E. the Mehlich III extractions. If I remember correctly, MIII is a mix of acetic acid, ammonium-nitrate, nitric acid, ammonium fluoride and EDTA; it reeks of acetic acid.

Texas Soil and Plant Lab's site states that they use "Albrecht's system of fertility balancing" for their recommendations. Please lead me to a peer review journal who accepts research papers on vegetable production based on Albrechts theories, I'd like to read one. Times have changed, so their might be one or more.

Kimmsr: Since you brought up Von Liebig, would you care to expound on your statement, particularly where he had it wrong? Do you fully and intimately understand the process universities use to develop a fertilizer recommendation for a particular crop? I'm guessing you may but am not certain. I whole heartedly agree that soil testing is only one tool in developing and maintaining a healthy, productive soil and it most certainly is not the total sum of all knowledge necessary to create a healty soil. Who tests their soil every month?

Good night and sweet dreams,

Michael

P.S. thank you both, this stuff is excellent therapy for my brain, my doctor (neurologist, not psychiartist) highly recommends it.

The University of Maine (they probably all do this) offers me the choice to have my recommendations given in organic or non-organic terms. I may be told to spread 12 bushels of sheep manure (or other manure or meals), 2 lbs. of rock phosphate, 4 lbs. of magnesium lime or something like that.

Leibig found that most plants had a lot of Nitrogen, Phosphorus, and Potash in their systems and determined that is all that needed to be put back into the soil, and that is what our current "conventional" gardening is based upon, that all that is needed to grow plants is a bunch of N, P, and K. We know today that is wrong. We know today that plants need a lot more and that soils need a lot of organic matter to grow strong and healthy plants. There are, however, lots of people that will not admit that and stick with Leibigs erroneous concepts.

Hi Kimmsr: About only needing NP&K only, agreed. Mineral soils are cabable of supplying many elements under favorable circumstances. There is one exception to the need for organic matter in growing a healthy plant, hydroponics, but that is a whole different world.

My limited memory of Von Liebigs theory is that once all growth factors were satisfied for plant growth, one could become limiting, I.E. not enough present. That one limited factor, say Fe, if not raised would be the sole limiting factor to growth. If the limiting factor was then raised, growth would then increase. I believe (perhaps incorrectly) he theorized that one only need to find the limiting factor and growth could proceed, and that this could be continued ad infinitum. Is ad infinitum what you find to be erroneous? I don't recall (which isn't saying much) Von Liebig refering to NP&K specifically or exclusively.

Michael

Fortunately farmers will accept productivity increases over peer reviewed journal articles. The watermelon example, if I remember correctly, was a correlation of soil and plant uptake of nutrients on a weekly basis throughout the year. When the correct nutrients are provided at the right time, the plants bloom all year and produce fruit all year. That is the gist of pecans, too. Pecans fruit only once every other year, at best. When proper nutrients are provided at the right time of the year, they fruit every year in abundance. As long as these farmers have a competitive advantage, they are not likely to submit their findings to peer review. The sodium sterilization is a typical problem you find around oil wells. A brine mix is used to flush oil out. That brine is just washed out into the surrounding soil and prevents plants from growing. By balancing the sodium with other ions, they are able to restore the soil to life. Probably any lab could have done that but TPSL was the one that did it. The watermelon and pecan examples absolutely had to have excellent correlation between soil analysis and plant uptake or they would have been guessing. To me I have to wonder what the universities are doing if they are not making farmers more productive by leaps and bounds.

I talk about this next example way too much but it sort of applies. I have personally talked to four ranchers who are beating the pants off of their neighbors in the profit department. They all follow the same methods and techniques, almost to the letter. They have been doing it for 20 years in a row so it's not just an anecdote at this point. Still Texas A&M cannot duplicate their results. It is hard to argue with a commodity based retail markup of 2,000% when the neighbors are only getting 155%. Sustain that over 20 years and pretty soon you're talking about real money. But the university claims the ranchers are not divulging everything they know or they are cheating. In this case I think the university is taking a short term look and the ranchers are looking into the deep future to make their decisions. Some of this mentality may be seeping over into other parts of the agriculture school.

Howdy DC: Lets see, watermelons first. The crux is, by maintaining proper soil nutrients (for plant uptake) adjusted on a weekly basis allows a much greater production period? Would that extend out to possibly turning an annual plant into a perennial or pseudo-perennial in theory. By example I mean maybe you could plant a watermelon crop in ths spring of 2009, harvest through the entire year and then continue on at least into the summer of 2010. The correlation was between soil nutrient levels and plant nutrient uptake on a weekly basis? I assume nutrient uptake was a measure of certain nutrients found in a particular part of the plant tissue.

Peer reviewed science. I'm guessing, but the vast majority of farmers probably don't know what a peer reviewd journal is, that's fine, if I was farming it is unlikely I'd have time to read them let alone keep up with the science in more than one field. Really it is the job of extension services to bring the information obtained from research to the field level. If you asked any grain farmer whose family has been farming for at least 2 generations I think they would say that productivity has increased dramatically over the last 100 years. So long as the research continues, I expect that trend to continue though, others would disagree for a number of reasons. One reason for my optimism comes from examples such as yours about the 4 ranchers. This indicates to me that all of the unknown still exists waiting to be discovered. The research conducted at universities has limited value unless it has passed what is essentially the gold standard in science, peer review. In the horticultural sciences, that means passing peer review by organizations like The American Journal of Horticultural Science. An equivalent in medicine would be The Journal of the American Medical Association. That is not to say farmers can only learn from extension services. Know doubt you know of private consultants. Having been one myself, I know they can have some distinct advantages over universities. They especially learn from a wide spectrum of literature and experiences. If I was farming for money, I'd take it where I could get it, even if it was from the back of a cereal box, BUT NOT WITHOUT SCRUTINY AND EXAMINATION.

Speaking of Ag schools, I've been in touch with a friend of mine at one lately. Until the last 5 years or so, the school was an excellent research university, among the best in this country if not the world. He tells me it is going down the toilet, that they have lost their focus and sight of their mission. Very unfortunate. Ag research AND farmers have been a Tour de Force in this country for many decades.