When it comes to growing a garden, if a little fertilizer is good, a lot is better. Right?
Not really. Fertilizer applications should match the needs of the soil and plants. Too much fertilizer, especially applied to smaller areas, can create more problems. One proven way to avoid overfertilizing is to invest in a simple soil test. It’s a tool that gives the most accurate method to tell the fertility of a garden, lawn, field or pasture.
“It’s important to get a soil test to know how your garden will grow over the season,” says Tegan Deeney, a lab tech with CSU’s Soil, Water and Plant Testing Lab in Fort Collins.
“I tested my soil when my pumpkin plants started dying when they were only two inches tall. My soil test showed there wasn’t enough nitrogen nitrate in the soil, and there was a simple fix.” She says a lot of pumpkins grew that year after she amended the soil with the recommended nutrients.
“The earlier you test, the better. You won’t run into the issues of trying to amend the soil around plants,” she adds.
Instead of guessing what your soil needs, a routine garden and landscape soil test will give you the specifics. For the $35 fee per sample, you’ll get results on soil pH, EC (Electrical Conductivity measures the available nutrients in the soil), organic matter, nitrate, phosphorous, potassium, zinc, iron, copper, manganese, boron, lime, and texture estimates.
In 2015 CSU’s Soil Testing Lab evaluated 2700 soil samples from horticulture alone. That total doesn’t include research soils or soil samples from farmers.
A soil test uses samples collected from the yard, garden or field. Soil sample collection kits are available from CSU Extension offices or some garden centers. CSU’s Soil Lab website has soil collection forms, instructions and a list of participating garden centers. For more information contact the lab at 970-491-5061.
A typical sample uses only two cups of soil that’s a combination of 5 to 15 samples (depending on the size of the area). Here are the basic steps for collecting a sample:
1. Use a clean, rust-free trowel or spade.
2. Collect samples at a depth of 6 inches; dig straight down, not at an angle.
3. Take at least 5 samples of soil from the area and combine in a clean plastic container.
4. Remove about two cups of soil and allow to air dry.
5. Place the sample in a CSU soil container or a sandwich-size plastic bag.
6. Seal and label with name, address and location of the sample.
7. Send the sample to the testing lab.
The turnaround time for results is about two weeks. Results will be mailed to you or include an email address for a faster reply. The lab results will tell you which nutrients your garden needs or if there’s an overabundance of nutrients.
With all the time, money and effort it requires for successful planting and growing, it makes sense to invest in a simple soil test. Consider it a gardening investment, almost like buying a plant insurance policy.
By Jodi Torpey
Denver Master Gardener