Soil testing

[seedcorn]

If you are into soil tests, do them at the same time of the year every time. Same sample taken at different times of the year will read different. Why? It just does, really don't care why.

Depending upon how you garden, you may have several profiles in the same garden.

Ph will also make a huge difference on what is usable and what isn't.

I could go on, but key is know what your plants are to look like. If they look normal, they probably are. Realize a soil sample is 1/2 pound of soil trying to represent tons of soil.

 

[MontyJ]

Yep, same time every year is best. Fall is the optimum time for several reasons. First, the soil is likely to be as depleted as it will get. Second, it gives you a chance to apply some amendments before putting the garden to bed. Some amendments take time to work, like lime or sulfur.

You can certainly have different soil profiles depending on how you garden. It's important to take samples from each area and have them tested separately.

pH is critical to many soil nutrients. Here is an example:

In a garden with a pH of 4.9 the gardener suffers a near total loss of his tomato crop to BER (blossom end rot) and blossom drop. Why?

pH is a measurement of how acidic or alkaline the soil is. Why is that important? If you think about the terms acidic and alkaline, the answer starts to become clear. Soil is composed of many minerals and metals such as potassium, calcium, zinc, boron, aluminum, and even lead. In simple terms, an acidic soil is just that, acidic. If the pH level is low enough, the soil acid levels will be strong enough to dissolve the aluminum component of the soil. This free aluminum will now be in a form that is capable of occupying CEC sites, restricting the amount of calcium available to plants, especially in low Ca soils.

The CEC is basically a reserve of certain cations in the soil. Cations are positively charged ions such as Calcium (Ca), Potassium (K), Magnesium (Mg), and Hydrogen (H). These cations become available as they are dissolved by soil acids and become soluble. These cations attach to particles in the soil such as clay and are then transferred to plant roots. The soil only has a certain number of points for the cations to attach too. The measurement of this number of points is called the Cation Exchange Capacity, or CEC.

Another part of the CEC are the Base Saturation and Nutrient Saturation, or how many exchange sites are occupied by what cations. This is important to know because plants can only get these certain nutrients from the CEC sites.

Now, let's put this all together so we can see why a low pH can cause BER in tomatoes, squash and zucchini.

As the pH level drops, the soil becomes more acidic and eventually reaches the point that aluminum becomes soluble. Plants have no use for aluminum. Soluble Al is a positive cationuh oh. What do positive cations do? They attach to CEC sites. In this case the soluble Al attaches to sites that would normally be occupied by calcium. Calcium is used by plants to build strong cell walls, among other things. Since Calcium is also immobile in plant tissue a Ca deficiency will be first noticed in growth tips and the ends of fruits where the deficiency is greatest. The weaker cell walls collapse and die resulting in sunken dark areasBER.

So, in our low pH soil, we have excessive soluble Al taking up the CEC spaces that Ca needs to occupy. The plant is not getting adequate Ca and suffers BER and poor growth.

Remember that this is only one possible cause of BER. Low soil calcium can also cause it in soils with a normal pH because there simply isn't enough Ca in the soil to begin with. This is rare however.

Yes a soil sample is 1/2 pound representing tons of soil. But the average garden has tons of soil that is exactly the same.

 

[seedcorn]

Monty, think you would be surprised at the huge differences in an average home garden. Especially those that hand feed plants.

 

[Smiles Jr.]

Wow! I stand corrected. I think I'm loosing it. I know that wood ash is alkaline, I just had it bass ackwards. Don't get old .

 

[seedcorn]

Wow! I stand corrected. I think I'm loosing it. I know that wood ash is alkaline, I just had it bass ackwards. Don't get old .

Smiles, the only option to not "get old" is death--I'm not ready. How about you? As my Dad said, old age isn't for the weak.

 

[Smiles Jr.]

. . . death--I'm not ready. How about you? As my Dad said, old age isn't for the weak.

No I'm not quite ready yet. I still have a couple of things on my bucket list. But now I'm scared to jump out of a plane.

 

[MontyJ]

Monty, think you would be surprised at the huge differences in an average home garden. Especially those that hand feed plants.

OK seedcorn, I get it. You are obviously against soil testing. That's fine. Show me a bona fide statistic where most home gardeners hand feed their plants. Granted, the raised bed gardeners might, and probably do, but those like me that garden 4000 square feet plus probably do not. And answer me this: How do you know what to hand feed each plant without knowing where you are starting at?

I think you would be surprised at how average most home garden soils are. I'm not talking about plant specifics here, just basic soil health.

In fact, I have a few questions for the community here:

Who hand feeds each plant individually? How do you know what to feed it? How do you fertilize your garden? Do you know your pH? How about your CEC?

 

[seedcorn]

Monty, I'm not against soil testing at all. Just pointing out areas of concern. Testing can be skewed, samples can be, plus people get all excited about something that is of no concern. If all plants doing well, I spend zero effort on soil testing. Upon looking at leaves, you can see what is lacking.

In Ag we use soil sampling a lot. We apply only enough nutrients for a desired production goal. Most home gardens have more than enough nutrients.

 

[897tgigvib]

I see a bunch of other answers and discussion, but without looking at them, which im sure are fine words, let me say what I notice:

That soil sample is what I call strong!

The ph is up a tad
the sulfur is up also
the sodium is up there
and a couple of those metals seem high to me.

In fact, just looking at this, I would think bioremediation would be a good idea, at least for awhile.
Along with that, some, no, lots of clean compost with neutral numbers needs to be added.

Something happened to this soil. There are bioremediation plants to grow that along with a big mix of fresh neutral soil can help it.

I wonder if I'm right

don't know what all the numbers mean, but they look like the wrong balance.

 

[897tgigvib]

...thinking...i wonder if this is the result of too much miracle grow...