Soil testing

[seedcorn]

How do the plants look? Do they produce? If the answers are good and yes, you are great.

IF that were the analysis for a field, it would get leached to bring it down. Government regs would require it for the P and K readings.

Want to get a jolt, sample the water that runs off after a rain.

 

[897tgigvib]

What's the water readings jolt going to be?

 

[Southern Gardener]

How do the plants look? Do they produce? If the answers are good and yes, you are great.

IF that were the analysis for a field, it would get leached to bring it down. Government regs would require it for the P and K readings.

Want to get a jolt, sample the water that runs off after a rain.

Then I'm great, because I had a good garden last year and still have brussel sprouts and cabbage growing now.

Yeah, spill about the water - although I'm scared!

 

[Ridgerunner]

Im a little surprised there are not some recommendations on the report of how much of certain stuff to add. Mine told me how much lime I needed to add per 1000 square feet to get my pH up where it should be. It also had a recommendation on how much 13-13-13 fertilizer to add per 1000 square feet.

Your pH is high. Your sulfur is low. Sulfur is acidic and will lower pH. Sulfur is what I use to get the pH down for my blueberries. You can get a small bag at a garden center. If you want to try to tweak it you can try adding some sulfur. I dont know what a lower pH would do with all that other stuff being so high. Im not an expert on this stuff. I just know enough to get myself in trouble.

I think what Seedcorn is talking about with the water is that some of that stuff is water soluble. How soluble will depend on what kind of chemical compound it is in, but when it rains a lot of that stuff gets dissolved in the water. The runoff can contain quite a bit.

 

[canesisters]

How do the plants look? Do they produce? If the answers are good and yes, you are great.

IF that were the analysis for a field, it would get leached to bring it down. Government regs would require it for the P and K readings.

Want to get a jolt, sample the water that runs off after a rain.

I'd rather get my jolt from coffee, field run-off would probably leave grit in my teeth.

 

[majorcatfish]

Major, not to be contrary, but a healthy garden will not be helped with a soil test.

Now if it's not healthy, by all means start with a soil test. Or if I'm planting a very temperamental plant, start with soil test. But if I have a healthy garden, I would not change anything regardless what a soil test said.

Secret to a great garden? Somehow convert your soil type to a sandy, clay loam with a high organic matter and make it rain timely. Oh yes, add sunlight.

i agree with you if the test comes back good, let it roll .... if not add what you need...

 

[MontyJ]

Oh, I'm not giving up on composting! But my pH on my garden read 7.28 - and the herb garden read 7.5 -

Here is the reading on the vegetable garden:

pH - 7.28 - very high
Phosphorus, ppm - 97.47 - very high
Potassium, ppm - 172,07 - very high
Calcium, ppm - 1,853.16 - very high
Magnesium, ppm - 363.43 - very high
Sodium, ppm - 78.23 - optimum
Sulfur, ppm - 8.81 - low
Copper, ppm 2.03 - high
zinc, ppm - 10.82 - high
Soil Texture: silt loam

The instructor said my soil was great and the only thing to add would be nitrogen when planting. Any rebuttals?

There are a few things missing from this soil test that I really like to see. OM, CEC and saturation levels. Without the saturations I can't determine the Ca:Mg or K:Mg ratios. I'm not one of those believers in the "perfect ratio", but I like to know what it is. I don't see any problems with this soil test. It's curious to me that the lab would consider the P, K, Ca and Mg levels as very high. As compared to the Ca, the Mg does appear high, but without the CEC saturations it's hard to say. The K will keep the Mg in check at those levels so the soil actually has a pretty good balance. I would also consider the Cu to be dead on at 2.03. Zn is high, but not outrageously so. All in all, I agree with the instructor. The pH is running on the high side, but not out of this world. Finished compost runs nearly neutral to slightly alkaline. It's very unlikely that it would raise your pH any.

Just out of curosity, have you ever limed the garden? I am going to guess that you probably have not and have a naturally high pH. If you have limed it, I would guess that you probably used dolomitic lime. That would explain the Mg. Excessive use of epsom salts can also raise Mg levels, but I would expect to see the sulfur level higher.

 

[Southern Gardener]

Monty, what is OM anc CEC?

I did use lime a couple of years ago, but hardly any at all so I don't think it made a huge difference.

 

[Ridgerunner]

That's the quandary. The test did not come back looking really great. There are several things that look wrong with it, several things too high and sulfur lower than optimum. But the garden still produces pretty well. How can that possibly be?

Its possible its a bad soils sample, either from contamination or it was not taken from places that give a true average. Maybe it was taken right after the soil was fertilized? But it sounds like Southern Gardener had two different tests run. If both came back in the same ballpark, then its probably a good sample.

Or maybe you have plenty of the stuff the plants need but not enough of them for any to be toxic. Maybe very high for most of that stuff is not a problem as long as it doesnt go over a certain limit. Just try to not add any more of those to the soil as best you can. This is my guess and it would help explain the comment by the Master Gardener, but as I said in another post Im no expert.

I think another part of this may be that the soils test measures how much is in the soil. I dont think it measures how much is in a form the plants can use. I could be wrong about that. Most of this stuff is not in there in pure chemical form. Its tied up in different chemical compounds with other chemicals. Maybe some of that is not in a form the plant can use. The pH is certainly higher than optimum for most vegetables but I dont know how closely the correct optimum pH is tied to how much of the other stuff is present in the right amount. It may be that the higher pH is not nearly as big a problem in this soil as it would be if those elements were present in the correct amounts. If you do add sulfur to get the pH down to the right range, you might actually create a problem with some of these other things being high. This is where Id want to talk to a real expert before I did much.

I have a whole lot of respect for Mother Nature. Some plants have a very tight window of conditions they require but a lot can grow in a wide range of conditions, especially if we take out their competition by weeding.

I tend to agree with Seedcorn. If it aint broke, dont fix it. But Id still be willing to talk to an expert and see if I could maybe fine tune it a bit.

I see MontyJ posted whike I was typing. I'll hit submit anyway.

 

[seedcorn]

How deep did you take the samples. How many spots did you sample? How large of an area are we talking about in general? There are other questions but no need. Bottom line, if the garden is doing very well, DON'T MESS WITH IT! Soil samples are meant to fix problems or to utilize the potential a field has vs. over fertilizing which means you spent more money than you had to to get the same result.

Need to fix something? Go to another spot in that you own that isn't doing well, fix away, and yes start with a soil test. Or go help some retired person or a newbie to gardening.

Yes, when you have high reading, the run off water will be full if it so your plant food will be in streams, city sewage, etc. A lot is not always better.