Accurate garden soil testing?

[jymbee]

Getting near time to start the vegetable garden again. Thinking that perhaps this season rather than my usual "plant and pray" methodology I'll try too apply at least a minimum about of science. Testing the soil seems like a good place to start. But the last time I tried one of those meter testing gizmos with the prongs you stick in the soil, readings were inconsistent with different results in the exact same area even.

Perhaps the test kits with the different chemicals are the way to go? Even there it seems there's dozens of options out there. Can someone recommend a specific product they've tried and liked?

 

[RalphVa]

I bought a test kit at Lowes that wasn't too difficult to use. Tested several things. Southern States probably has them, too, or your local Farm Bureau store.

Best is to go to the extension office and get their "kit" for soil testing, which is basically a folded box and instructions. You mail the sample to the extension uninversity sponsoring the extension office. Here in Va, it's been $10. Could be higher now. Haven't worked there in over a year.

 

[Jstpssng]

Getting near time to start the vegetable garden again. Thinking that perhaps this season rather than my usual "plant and pray" methodology I'll try too apply at least a minimum about of science. Testing the soil seems like a good place to start. But the last time I tried one of those meter testing gizmos with the prongs you stick in the soil, readings were inconsistent with different results in the exact same area even.

Perhaps the test kits with the different chemicals are the way to go? Even there it seems there's dozens of options out there. Can someone recommend a specific product they've tried and liked?

I sent mine out to the local Extension Service last year. In your state, Cornell University https://cnal.cals.cornell.edu/analyses/
provides the same services. I also recently bought a DIY kit https://www.amazon.com/Environmenta...hvlocphy=&hvtargid=pla-4583589101746874&psc=1.
I've only used it once so don't know how it's going to work out.

 

[ponytug]

Having used a couple of "home use" soil testing kits from HD and a local hardware store for some field testing, I would say use the big labs via your county agent. The home kits weren't even close to accurate.

On the home garden, I add six inches of composted manure and rototill it in which seems to work well, but my climate seems to really use up organic material.

All the best,

Peter

 

[jymbee]

I sent mine out to the local Extension Service last year. In your state, Cornell University https://cnal.cals.cornell.edu/analyses/
provides the same services. I also recently bought a DIY kit https://www.amazon.com/Environmenta...hvlocphy=&hvtargid=pla-4583589101746874&psc=1.
I've only used it once so don't know how it's going to work out.

Thanks much for the info/links. The folks at Cornell are probably a bit more scientific about this stuff than myself.

One consideration is that I have a number of different garden plots & raised beds, each with different soil from various places so I may try the lab route for the main garden and a self test of some kind for the others.

It would be interesting to see how the two-- Cornell labs & DIY kit-- compare. I'll follow up with that info later.

 

[BeezFun]

The other nice thing about the lab tests is I got a letter describing what the results meant and how much of what to add to improve things. I used our local extension office.

 

[CADplans]

My 10 year old granddaughter is a STEM WIZ for her age,,
she loves learning anything about science, chemistry, or math,,

So,, I ordered a half dozen pH test strips packs,, and we set about testing EVERYTHING that we could find,,
(Test some "Greased Lightning" cleaner,,, SUPER alkaline!!)
The result was, we developed a belief that the test strips were accurate,,

Well, we have always been told that our rain is "acid" due to fossil fuel combustion,,
things must have changed,, I have collected samples from the last three rain storms

EVERY sample of rain tested above 7.5pH,, not what I was expecting.
Reps from Va Tech have always told us that we need to add lime,,
I think I am gonna call "BULL" on that one,, I think I need to add sulfur.

I added a LOT of sulfur to the area that we have tried to grow blueberries,,
it turns out , even with adding sulfur, I can not move the pH off of 7
and, yes, I have waited,, a year in fact,, the sulfur does not seem to be strong enough,,

I am gonna do whatever is necessary to move my pH,, even if I have to start spraying gallons of muriatic acid,,,

So, in other words,, I would not trust the soil tests that Va Tech offers me,,,

 

[ponytug]

Wow, congratulations on the STEM whiz of a granddaughter! That sounds like a great set of projects. You could also take your rainwater, test it, add a pinch of soil, test it again, then a tablespoon, then a cup of soil and compare the pH levels. (Or the same thing with various soil amendments to see the pH shifts.)

Sulfur is a long term acidifier. For your blueberries you also need something shorter term, like a rhododendron fertilizer, or coffee grounds, or fresh horse manure. We have similar challenges with our roses. For sulfur, you need the bacteria in the soil to convert it to sulfuric acid and that is a slow process, further slowed by lots of rainfall washing the acid out. Think five to ten years for sulfur, and your blueberries probably need help now. We have very alkaline soil, and I have been dumping all of our tea and coffee grounds on our roses for two years and this year they are finally going bananas. I had chlorosis in one our garden beds and dumped a pound of sulfur in it. (6x10' plot) It might have started making a difference in two or three years, but by then, I was pouring on compost and other soil amendments, including fresh wood chips.

While with better air, due to enforcement of air quality regulations on things like coal burning power plants, the rain has gotten less acid. However, pH testing rainwater is actually very difficult as there is relatively little no non-water chemical in it (when you get acre feet of rainfall, it adds up, but in a glass or a bucket, it isn't much). pH test strips have a hard time in something as dilute as rainwater, because they actually have chemicals in the paper and can overwhelm the trace chemicals in rain. If you want accuracy, you would need a calibrated and sensitive electronic unit, and even then you would want to collect it in clean (unused, but rinsed) plastic and want to measure something like at least a quart. Does that make sense? It is hard to get containers clean enough for studying rainwater, rather like handling raw hot peppers- you never notice that there is anything on your fingers until it is time to relieve yourself... It is only a trace amount...

Now whether VA-tech can do a good soil test, I haven't a clue.

All the best,

Peter

 

[CADplans]

Wow, congratulations on the STEM whiz of a granddaughter! That sounds like a great set of projects. You could also take your rainwater, test it, add a pinch of soil, test it again, then a tablespoon, then a cup of soil and compare the pH levels. (Or the same thing with various soil amendments to see the pH shifts.)

However, pH testing rainwater is actually very difficult as there is relatively little no non-water chemical in it (when you get acre feet of rainfall, it adds up, but in a glass or a bucket, it isn't much). pH test strips have a hard time in something as dilute as rainwater, because they actually have chemicals in the paper and can overwhelm the trace chemicals in rain. If you want accuracy, you would need a calibrated and sensitive electronic unit, and even then you would want to collect it in clean (unused, but rinsed) plastic and want to measure something like at least a quart. Does that make sense?

All the best,

Peter

We have lived here 40 years,, and have changed the garden from light tan silty sand/clay soil to dark brown soil over 12 inches deep,, but, it has taken hundreds of tons of compost,, literally,,
One summer our county gave away chipped trees (from a storm) and I hauled 100 loads on my dump trailer,, 5,000 pounds of chipped wood per load,,
That alone was a half million pounds of compost,,
I think that is one of the reasons I find it difficult to shift pH,, too much "Ruth Stout" LOL!!

I also hauled in over 50 loads of free horse manure over the years,, that material was MUCH heavier than 5,000 pounds per load,, maybe even close to double.

It was something to do,, I never considered it work,, plus it was spread out over decades,,,

As far as the rain water, I capture it in a 150 gallon Rubbermaid cattle watering tank,, so the sample is large,,
I dump it between samples, as I usually do not need the water.

I guess I will do more testing,, it is a great excuse to order more pH testing stuff,,,

 

[ponytug]

I would love to have that much chipped wood available. Wow, though I am sure the storm must have been horrific.

I can relate. Our garden started as mostly subsoil, and it seemed like I put down a foot of compost over the whole thing and rototill it in every year and it would vanish by the next year.

Fifteen years later the soil is pretty nice. The gophers are doing great, too. So great that we don't garden there anymore...

Some things in soils are easier to amend than others...


All the best,

Peter