Did your vegetable garden not perform as you would have hoped last year? Healthy soil is the foundation on which a successful garden is built yet soil sampling, the first step in ensuring your soil is fertile and suitable for plant growth, is often overlooked. Collecting soil samples only takes a few minutes and it often leads to people saving money on fertilizer they don’t need.
While environmental extremes, such as excessive rain or dry spells, and pests and diseases can cause trouble, rarely is one factor to blame for an ailing garden. Regardless of what the causal agents may be, a very good place to start troubleshooting garden woes is to first take a look at the soil beneath your feet.
The steps required to submit a soil sample are simple and can be achieved using a few commonly found household items. Once the pH level and nutrient content of your soil is known, we can then begin piecing together the causal agent of your gardening troubles.
While soil testing is typically done in the fall or winter when most plants are dormant and the soil is most accessible, soil samples can be taken any time of year. One of the main reasons for fall and winter testing is because if any soil amendments need to be added, such as a lime application to adjust pH, it can take several months for the lime to react in the soil.
So, how often should you test your soil? Well, I’ll give you one of my favorite horticultural answers – it depends. For intensely cultivated soils, like vegetable gardens, UGA Extension recommends testing your soil annually. Otherwise, for lawns and ornamental areas, sampling may be done every two to three years after initially establishing medium to high fertility levels and the appropriate pH.
Recommendations on when and how to apply nutrients are only as good as the soil sample submitted for analysis. To obtain a representative soil sample, the following steps are useful:
- Divide areas so each soil sample represents a general plant type. For example, take separate samples for vegetable gardens, blueberry plantings, lawns, etc. If you have specific problem spots, sample those areas separately.
- Use clean sampling tools and containers to avoid contaminating the soil sample. Don’t use your fertilizer bucket for mix your soil samples! That will greatly skew the results and make you think you have nutrients in your soil that you really don’t.
- Collect your samples with any digging tool you have available, such as a hand trowel, shovel, soil probe, etc. Slightly damp soil is the easiest to work with, but don’t try to sample saturated soil after a hard rain.
- First, clear the ground surface of grass, thatch or mulch. Push the handle forward in the soil to make an opening, then cut a thin slice of soil of uniform thickness from the side of the opening, extending from the top of the ground to the depth of the cut.
- For lawns, sample to a depth of about 4 inches. For gardens, ornamentals, mixed fruit trees and wildlife plots, sample to a depth of 6 inches.
- Repeat the sampling process in a zigzag pattern across your defined area, collecting eight to twelve samples to mix together. For individual trees, take soil samples from six to eight spots around their dripline.
- The lab will need about a pint (around 2 cups) of the mixed soil. There is a pre-marked fill line on the UGA soil sample bag – be sure to fill your bag to that dotted line!
- If the samples are wet, spread the soil out over clean paper and let them air dry before filling the paper soil bags.
- Generally, it takes 7 to 10 days from the time your Extension office receives the samples to the time you get your test reports back.
The Fannin County Extension Office now has a sample drop box located next to their front door. Please leave sample along with payment in drop box for a contactless experience. Payment envelopes are provided.