Why Soil Test?
Getting a soil test done on your lawn gives you a picture of your lawn’s health, so you can make the right decisions when managing the yard. Don’t waste money on unneeded treatments if your lawn is already at healthy levels and find personalized recommendations for your lawn’s needs!
Through the City of Springfield’s Lawn Steward program, James River Basin Partnership provides free soil tests to homeowners in the city limits. JRBP staff will visit you at your house, discuss your previous and desired lawn care, measure your yard, and collect soil samples. The soil samples are then tested by the University of Missouri Extension office, and the results are interpreted to the homeowner in a report with an easy-to-follow three-year nutrient management plan.
Parts of the Soil Test:
Organic Matter
Organic matter is referring to the percentage of soil that is made of plant or animal matter, and it offers nutrients to plants growing in the soil. Soil with higher levels of organic matter does a better job retaining water and contribute to soil fertility. We always say you want to “stive for 5” meaning you aim for 5% or more organic matter in your soil.
Organic matter can be raised or maintained in a variety of ways. Leaving grass clippings after mowing and leaves in the fall will naturally increase the percentage. You can also apply a thin layer of compost to your yard. Learn more about applying compost here below.
pH
Soil pH measures the hydrogen within the soil, telling us if the yard is acidic or basic. Soil pH plays an important role in how much nutrients are available to plants. If soil pH is low, you may need to add limestone to increase the pH so more nutrients are available. (See below for lime application instructions.)
Nutrients
The MU soil tests show your levels of calcium, magnesium, phosphorus, and potassium.
Calcium: helps the soil structure and impacts aeration of the soil
Magnesium: used by a plant’s chlorophyll to complete photosynthesis
Phosphorus: works to store and transfer energy in plants, used for growth, reproduction, root growth, and the plants’ ability to withstand hard conditions
Potassium: needed for plants to utilize water
Phosphorus is one of the main nutrients we look at since it can dramatically impact water quality. We also focus on nitrogen, though that is not tested in the MU Extension soil tests, since nitrogen is difficult to assess in the soil sample. Most turfgrass lawns will benefit from added nitrogen, as it’s a standard recommendation for average maintenance of cool season lawns. To organically increase nitrogen and phosphorus, avoid bagging your grass clippings and consider a light topdressing of compost. Conventional fertilizers are also an option and will have to be personalized to your lawn needs. If too much phosphorus or nitrogen is added to the soil, it won’t all be utilized, and the leftovers can wash away with rain into local streams. Think you’re in the clear because you aren’t near a stream? Any water runoff that makes its way into a storm drain does not go to the water treatment facility, it ends up being discharged into the environment and into streams.
Lawn Care Recommendations:
How to Apply Compost
For best results, apply ¼” of compost evenly throughout your yard. It is recommended that you add 1 cubic yard of compost per 1,000 square feet.
Fill a wheelbarrow full of compost and create small, evenly spaced piles throughout your yard. Using a rake, spread the piles until evenly distributed. To avoid smothering your lawn, eliminate clumps and rake out deep spots so they are no more than ¼” in depth. Your lawn may look a little messy until the compost has been “watered in” by rain or irrigation.
Need an easier option? You may also use a compost spreader. Simply fill up the roller, close and secure the door, and then you can start spreading compost in even layers across your yard. You can check out a compost spreader from the Springfield Tool Library: cpozarks.org/programs/springfield-tool-library/
Tips on using a spreader:
Regardless of the type of spreader you plan to use, it must be adjusted to ensure even distribution of fertilizer and other materials. Recalibration may be necessary when using the spreader for other tasks such as overseeding or application of pelletized lime due to the different shapes and sizes of granules or seeds. The easiest way to apply is to set your spreader on the lowest setting and make multiple passes.
Place your rotary spreader inside a container or on a tarp to catch any spills that may occur while filling. This prevents waste and eliminates the risk of excess materials being added to your lawn.
Where do you find compost? Bulk compost may be purchased at several local landscape suppliers as well as the City of Springfield’s Yardwaste Recycling Center located at 3772 County Rd. 119, Brookline, MO. Call ahead to check on availability and rates. A standard pickup truck can help approximately 1-2 cubic yards of compost. Ask an employee how much they typically load into a vehicle of your load rating.
How to Apply Lime
The best way to apply lime is by using a rotary spreader. Set the spreader on its lowest setting before filling with the recommended amount of lime for your yard. It is recommended that you spread the lime in one direction, then the perpendicular direction. For example, make your first passes going north and south, and your second passes going east and west. Store leftover lime in watertight containers to avoid clumping and spills. Five-gallon buckets with lids are a sturdy, cheap, and reusable option.
Need a rotary spreader? Many common seed spreaders are a rotary spreader, including the ones available to check out from the Springfield Tool Library: cpozarks.org/programs/springfield-tool-library/
Core Aeration
Over time, soils become compacted from foot traffic and equipment use. It is recommended to core aerate your lawn at least once every 2-3 years to break up compaction, increase water infiltration, and allow organic matter to be quickly incorporated into the soil. It is best to core aerate before applying compost and/or lime, to maximize soil contact.
Core aerators can be borrowed from several local rental companies at hourly and daily rates. Spring and fall are popular times to aerate cool season lawns, so be sure to call ahead to check on equipment availability.
Adding Seed to Your Lawn
If you’ve observed thinning or bare patches in your lawn, it’s probably time to consider overseeding. Fall is the best time to overseed cool-season lawns because there are fewer weeds to compete with your newly planted grass. Following core aeration and compost application will allow for better seed to soil contact and improved germination rates. Be sure to follow up overseeding with frequent watering (2-3 times per week) until established.
Calculating Conventional Fertilizer Recommendations
If you wish to apply a conventional (chemical) fertilizer to your lawn, you will need to pay attention to the fertilizer ratios listed on the bag. The three numbers listed represent the amount of Nitrogen-Phosphorus-Potassium (N-P-K) found within that specific fertilizer blend. You’ll want to select a ratio that closely matches your recommendations, for example, 20-0-0 for nitrogen only application, or 13-13-13 for nitrogen and phosphorus. Once you have selected a fertilizer blend, there is a simple equation that will help you determine your application rate. An example is provided below. Feel free to contact us for help calculating a different ratio mix.
Let’s say you choose the fertilizer with a 20-0-0 ratio. The soil test recommends you add 1 pound of nitrogen per 1,000 square feet. To calculate your application rate, simply divide the amount of nitrogen needed per 1,000 square feet by the percentage of the nitrogen in the bag. Your equation would look like this: 1/0.20 = 5 pounds of 20-0-0 per 1,000 square feet. So, for a 2,00 square foot lawn you would need a total of 10 pounds (5 lbs x 2 = 10) of 20-0-0 fertilizer.
Too much math? Use MU Extension’s Lawn Fertilizer Calculator to find your needed measurements: http://agebb.missouri.edu/fertcalc/
Sign up to receive a free soil test and nutrient management plan from JRBP here:
Anyone in Greene County is eligible for JRBP’s Lawn Steward program thanks to funding from the City of Springfield, City of Republic, and Greene County.
This blog was created as part of a series to educate Springfield homeowners about the Yard Ethic program. Learn more at yardethic.com
