Soil Testing

The purpose of soil testing is to identify nutrient or content imbalances that would reduce plant performance.

We use the test both before planting to make corrections, as well as after to help in diagnostic analysis. It isn’t critical that you check your soil before every kind of landscape or garden project; every soil will grow some kind of a plant, even if only weeds! The black or dark brown topsoils of Illinois usually yield pretty good results without testing. But many of the homes built today have their topsoil stripped away, or covered by the poor subsoil excavated during basement installation.

Also, some plants such as blueberries or hydrangeas have specific requirements for soil acidity.

To ensure gardening success, have the soil tested three to four weeks prior to doing the work. Soil modifications and some fertilizations are done before working up the soil. The soil test report you receive back will indicate what adjustments you need to make to the soil. Soil modification may not be economically feasible for large lawns, although it can make a significant difference in the turf's performance. Compost, sphagnum peat, and manure can all be used as amendments to poor soil structure. By adding these to clay or sandy soils, you can improve plant performance through deeper rooting, better nutrient uptake, and improved disease resistance.

Soil fertility is amended according to the soil test recommendations. If phosphorous or potassium is needed, it should be incorporated into the soil; add nitrogen after seeding or planting. Rototill or cultivate fertilizers and amendments to a minimum six-inch depth. This function loosens compacted soil for easier rooting of plants.

Soil acidity, also known as pH, affects nutrient uptake in plants. It is especially important to understand pH when planting acid-loving plants. The pH scale runs from 1 to 14, with 7 being a neutral pH. Anything less than 7 is considered acidic and anything over 7 is alkaline. For most plants, a pH of 6.5 is desirable.

Most of the soils in Central Illinois tend to be alkaline, and that creates problems for acid loving plants like hydrangea or hollies. In such cases, pH can be lowered by amending the soil with granular sulfur. Soil sulfur works best when it is mixed into the soil and given up to a year to undergo the necessary reactions to lower the pH. It is, however, one of the best ways to make a lasting pH change in the soil.

For quick fixes, Miracid, Copperas, or any other acidic fertilizer can be used. Aluminum sulfate is often used with hydrangeas to obtain a blue flower color in the bigleaf hydrangea varieties such as Endless Summer or All Summer Beauty.

How to Collect a Soil Sample for Testing

• Note—It is easiest to take soil samples when the soil is somewhat moist. Avoid taking samples when the ground is too wet.
• Select the area to be tested.
• Take 3-5 soil samples from the designated area by using a flat spade to take a “slice” of soil
• A lawn sample should be taken at a depth of 4 inches. Tree, shrub, or garden samples should be taken at a depth of 7 inches. Discard the top 1-2 inches, since it usually contains mulch, grass, twigs or other debris.
• Combine the multiple samples in a bucket, and mix together well.
• From the mixture, remove approximately one cup of soil and place in a Ziploc bag. Please write your name and phone number on the bag.

Bring the sample to:
Hoerr Nursery
8020 N. Shade Tree Dr.
Peoria, IL 61615

Soil samples can be sent direct to
Mowers Soil Testing Plus
117 E. Main St.
Toulon, IL 61483

A small fee covers the cost of testing your soil.