Posted: March 6, 2024
It's almost time to start a new season of gardening. Are you ready? Do you need a soil test kit to ensure your soil has the nutrients it needs?
Are your seasoned gardeners itching to get into the garden? Are your new gardeners ready to begin your new hobby of making your world more beautiful and bountiful with flowers and vegetables? Does that wonderful smell of rich soil beckon to you even though it might be cold and blustery now? Why does soil smell like that, anyway?
I'm sure some folks studied their seed catalogs and ordered their desired varieties. Garden plans were drawn up to ensure we have room for what we want and to decrease the chance of frivolous purchases. Perhaps you have already started several plants indoors to put out in late March. But there's another gardening chore to do. What about your soil?
There are many factors in gardening we don't have much control over, weather for instance. We have only the soil on the piece of ground where the garden lies. Unlike the weather, though, we can work with the soil, even improving the poorest soil. A simple home test for approximating your soil texture can tell you the percent of clay, silt, and sand you have ( An instruction fact sheet is found at South Carolina's Extension at Clemson University. This tells you nothing about your soil’s nutrients, but it tells you a lot about whether nutrients and water are easily available to plants.
Why does the percent of sand, silt, and clay making up your soil make a difference? Sand particles are the largest, allowing water to drain quickly, even after a deluge. Silt particles are smaller than sand, and clay particles are the smallest. Clay particles hold nutrients and water, but soil with too much clay doesn’t drain well. Loam, the best soil, has roughly an equal amount of all three. The sand and silt hold the clay particles apart, forcing water to drain away slowly, and giving roots a better medium in which to get their nutrients.
My home soil texture test left me disappointed, but there are remedies – compost and mulch! Compost contains bits of organic particles called humus, which hold onto nutrients the plants need. Compost also feeds soil organisms, most of which you need a microscope to see. As these soil organisms break down the compost and release nutrients, humus and clay particles hold onto nutrients, making them available for plants. Applications of organic matter over the years have slowly brought my soil, once almost devoid of visible soil creatures, back to life.
What does good soil need? How do I find out what nutrients are missing? As I learned when I was a Master Gardener trainee, there is a lot of folklore to help you guess what is needed, but a soil test performed by the labs at Penn State gives you a definite answer and tells you how to replace what’s in short supply. You can obtain a soil test kit from the Adams County Extension Office at 670 Old Harrisburg Road, Gettysburg for $10.
When you open your test kit, you'll find a booklet with instruction pages for each different kind of planting. Vegetable gardens have different needs than flower beds, fruit trees, and lawns. Your soil can be different from one part of your yard to another, too. You need to purchase a different test for each of your gardens.
If you are testing for a new garden, be sure you have outlined the area to represent that space. Whether a new or existing garden, you need a representative sample. Dig 4-6 inches into the soil (the root zone) for each of 12 samples taken randomly through the garden space. Put them in a bucket and mix them thoroughly to ensure a representative sample. The instructions don't mention this, but I let the sample dry out and then screen it since I'm paying the postage when I mail it to State College. The cost of the kit only covers only the cost of the soil test, so don't pay to mail water, stones, gravel, and mulch bits.
When you are ready to take your sample to the post office, fill the sample bag provided with about 1 cup of dry, fine soil. Find the form for the garden you are testing and be sure to place the appropriate form in the mailing envelope. The results can take about two weeks.
The results come to you with instructions for amending your soil. Interpreting the results can be daunting the first time, but we have Master Gardeners on the Hotline who can help. The test measures pH and the minerals phosphorous, potassium, and calcium. Nitrogen isn’t tested directly, but recommendations for amending nitrogen are associated with the amount of phosphorous measured. Nitrogen exists in the soil in three chemical forms, and it changes between them constantly, and testing for them is difficult and costly. Besides telling you which nutrients are in the optimum range and which are deficient, there are instructions telling you how much of each needed nutrient to add.
Getting back to organic matter . . . There is one soil component listed among the obscure data in the test results. You may have missed it if you weren't reading all the information on the page. It's called cation exchange capacity (CEC), meaning there is something in soil – humus – that holds onto nutrients and makes them available to plants. This value tells you whether you have enough humus and organic matter to feed those hungry soil organisms, and how much to add if you don't.
And the smell of rich soil? Those are the bacteria that inhabit every surface of material in the soil. They are the base of the food web and they're busy digesting organic matter and releasing nutrients to feed our plants.
Debby Luquette is a Penn State Master Gardener from Adams County. Penn State Cooperative Extension of Adams County is located at 670 Old Harrisburg Road, Suite 204, Gettysburg, phone 334-6271.
Master Gardener Hotline is open Wednesdays from 10am - 2pm. Please send an email (with pictures if possible) to adamsmg@psu.edu with your gardening questions, or stop by Penn State Extension, 670 Old Harrisburg Road, Gettysburg.
Ecological Landscaping, March 21 & 28 and April 4, 11 & 18, 6:30PM – 8PM: Gain insight into the impact homeowners wield on water conservation, pollinators, and local wildlife. Through hands-on drawing exercises, explore concepts such as meadows, native plants, and effective water runoff management, aimed at transforming your landscape. Each class builds upon the last. To register: https://extension.psu.edu/ecological-landscaping
Selecting Trees for the Landscape: Wednesday March 27, 6:30PM – 8PM. When choosing plants for the garden or yard, there are so many choices! Join this class to learn about the function and aesthetics of trees. The environmental impact and needs of these plants will be discussed. To register: https://extension.psu.edu/selecting-trees-for-your-landscape
Visit us on Facebook and Instagram at Penn State Master Gardeners in Adams County for our Master Gardeners’ Monthly Videos. Timely and relevant topics will be discussed on a regular basis keeping readers up to date on current horticultural issues.
