Wednesday, October 31, 2012

Soil Testing is a Valuable Gardener's Tool

Well that was exciting.

We spent about 26 hours in the dark and nearly 48 without phone/cable/internet, and for my son nearly a lifetime without XBox.  And with school out, he had to go old school when hanging out with his friends.

The image to the right is a large Norway Maple that was living in the 3' sidewalk strip that went over at 4pm on Monday afternoon and took all the power and cable lines with it.  It impacted about 200 homes in the neighborhood.

No one I know was injured and things seem to be getting back to normal and the clean-up has started.

I have no natural segue into my post on soil testing so here it goes anyway.
Want to do something cool this fall for your garden and bring back some of those old high school chemistry memories (or nightmares)?

Test the soil in your garden.

After you get the leaves and branches cleared up, or anytime up until the ground freezes, look to test some beds in your garden where plants might not be thriving or flowering to their potential.

Digging with a trowel
Why would one care to do this?  Do you have plants that are supposed to flower but do not flower regularly or at all?  Do leaves on your plants turn yellow and do the plants look a little barren with some dieback?  Does your soil look like a Dunkin Donuts coffee with cream, or a Starbucks Dark Roast?  Do your plants look like they are just sitting there year after year and not thriving and growing and looking lush and happy?  Do your have Blueberries that don't berry or annuals that don't do much after you plant them in the spring?  Do you grow Asparagus but not really have much to harvest?

If anything in your garden is not thriving, a soil test will help you to answer the question, why.  It will also make specific recommendations for how to remedy the problem.

Soil Sampling Tool
Locally, I use the UMass Soil and Tissue Sampling Laboratory, it is the best $15 (per sample) you can spend in your garden.  I suggest you try and break down your garden into separate beds to test.  If you have a vegetable garden, that should be one test.  A perennial bed would be a separate test.  Your front foundation would be a separate test.  Ideally you want to get several (5-10) different small samples from each bed you are testing and blend them into one sample.  This will tell you generally what is happening in a specific bed and minimize the chance of one sample skewing the result.

A previous post, It's all about the Soil, goes into great detail about soil structure, pH and nutrients.  If you want an in depth discussion about all the details, the post covers most of the bases.  The previous link also goes into great detail about the information that will be contained in the results of your soil test, but the lab should also supply quality information.

This post will go through the details of how to collect good soil samples.

Separate the top part
from the soil in
the root zone
When collecting the sample to submit to the laboratory, it is critical that you get soil from the root zone where the plants retrieve their nutrients.  There are two easy ways to obtain samples.  First you take a hand trowel and scrape away the surface mulch and dig down 6 inches into the soil.  The soil at the bottom of the hole is what you want for your sample.  If you have a bed of Rhododendrons that you are testing, dig half a dozen holes around the bed and blend the soil you get from the bottom of the holes.  The second, and easiest way to collect samples, is with a soil sampling tool, a long, hollowed out metal rod that you can push into the soil.  When you push the tool into the soil and remove it, the hollow rod contains a long core of soil.  You can remove the top six inches and take the remaining several inches from deep in the root zone.




Lay out the soil for drying
When you have your group of samples you need to lay them out to dry.  In the image I have used old birthday plates as the drying rack.  Once the soil is on the plate you can break up the clumps, remove any big stones and remove the stray piece of mulch that may have gotten into the sample.  After a day or two, the soil is dry enough to be bagged, labeled and sent to the lab.  Take care not to mix soils or label improperly, because if you apply the wrong item to resolve a problem to the wrong bed, you may end up killing some plants.

Rocks and twigs removed and clumps
broken down, ready for sample
When filling out the paperwork, the form will ask you to classify the plant material in the bed you are testing.  Filling this out appropriately will result in the lab providing you with accurate instructions for remedying any problems.  For example, if one of your beds contains Rhododendrons, Azaleas and Mountain Laurels, you would classify that as "Acid-loving Shrubs"(see form).  If the results say the bed has a pH of 7.1, it will tell you how much acidifier to add to the bed to achieve the proper pH.

UMass does an excellent job of eliminating the guesswork, but their test results and suggestions are only as good as the samples they receive, so spend the time and collect good quality samples.

Come early spring, you will be armed with information to improve the environment of your planting beds, and in short time you will start to see results in the health and vigor of your plants.


If you grow vegetables, this is a must for ensuring you do not have high levels of metals and lead in your soil.

Packaged, labeled and ready to go




1 comment:

  1. Good post. I had a soil test earlier this year and learned a lot. As for your son's Xbox deprivation, be brave. The scars will heal.

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