How to Take a Good Soil Sample for Testing


Hi, I’m Tricia, a California organic gardener, and I want to get to know my soil better! I figure if i don’t know what the
deficiencies are i could waste money on amendments, or I could put my garden at
risk. To avoid that, I’m going to take a soil sample and send it away for testing! When the results come back, I’ll know if i need to add some nitrogen for
vegetative growth, or perhaps some phosphorus for fruiting, flowering and root development, potassium for disease resistance or maybe calcium for sturdy cell walls and pH adjustment. or maybe i’ll find out that my soil’s
healthy just as it is! Take it from me, it’s really important to
take a good soil sample and that starts with using a good tool. I’m going to use this clean cast aluminum trowel with measurements on it. Don’t use brass, soft steel or your hands to take the sample. I also have a clean plastic bucket to put
the soil samples. You don’t want to use galvanized steel or
rubber because that could also contaminate the soil. I have several raised beds so I want to take a different sample for each bed. Last season there were different crops
growing in each bed and so the soil nutrients were depleted a little bit
differently. I’m going to take about 12 sub-samples
from each bed, that way we have a good composite of what the soil is like. Be sure and clear away any debris, leaves or any other organic matter from the surface of the soil. For vegetable gardens you want to dig down about 6 inches, or as deep as you plan to till or cultivate. So you want to dig a cone shaped hole as I said about 6 inches deep, and then you want to scrape the sides of that hole to get the strata of the soil. You want to be sure and pick out any debris like roots or little stones or whatever before you put the soil in your bucket. Repeat this processes in a zigzag pattern. If you’re not growing in a raised bed, Try to make the sample distances
about five to ten feet apart and avoid small areas of obviously different
soil like a manure pile or a path because that can skew your results. You want dry soil. If the soil is too wet to plant, then it’s too wet to sample. if your soil is wet, spread it out on a newspaper in a location with good air flow and out of the sun a day or so before putting it in the bag so it doesn’t mold. Never use heat to dry your soil! I’m going to take about a pound of it and put it in this little bag, which is all ready to be sent off for testing. Most gardeners just need a basic soil
test which includes nitrogen, phosphorus, potassium, pH and organic matter. However, if you’re starting a new garden or if your soil has never been tested before, you can also get a micro nutrients test. This test for micro nutrients such as zinc, copper and manganese. So in a couple of weeks I’m going to get my test results along with an interpretive booklet which
will have some suggestions for organic fertilizers that correct deficiencies. So get to know your soil, and Grow Organic for Life!

5 thoughts on “How to Take a Good Soil Sample for Testing

  1. Where do you send your soil samples? Curious if you have the test do organic matter and soil type evaluation as well as what you cover?

  2. dtriplat, Our Complete Soil Analysis Report includes lab readings for tests for zinc, manganese, iron, copper and boron in addition to organic matter, estimated nitrogen release & nitrate nitrogen, phosphorus (weak bray & sodium bicarbonate P), extractable cations (potassium, magnesium, calcium, sodium), hydrogen, sulfate sulfur, pH & cation exchange capacity and percent cation saturation and excess lime.

  3. Dry enough that if it was around your plant you would water it. 12 hours of air drying at room temperature is sufficient. The drying is mostly to speed processing times at the lab and reduce shipping costs.

  4. Right, thanks.

    It'll have to wait now till after the next shift, so it'll be even dryer!

    Doing my own, not sending mine, though.

    Cheers

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