Amendments to the soil are almost always necessary to provide the good nutrition which is required for optimum plant growth. The primary nutrients are Nitrogen (N), Phosphorus (P), and Potassium (K). These primary elements are found, to some extent, in every soil, however, after many years of farming or wooded plant growth, some of each of these elements has been used up by the growing plants. Thus it is necessary to supplement what is naturally present with additional quantities of these elements. We do this by the application of fertilizer. However, the quantity of fertilizer which is needed is impossible to tell without a soil test.
Soil tests are preformed by several reputable laboratories in the region for a very nominal fee. A list of these labs and their contact information can be found at the end of this guideline. It is strongly suggested you have your soil tested prior to ordering your sod so that you can apply the nutrients which are required for the sod plants and at the same time do not apply excessive amounts of fertilizer which can become detrimental to our waterways and environment. These tests usually take approximately a week to get your results and will in the long run save you money and worry. Simply contact any of these labs, and they will provide you with sample containers and the proper forms for the information they will need to process your sample(s).
To take a soil sample, use a clean bucket and a garden trowel. Survey your area to be sodded. If it all appears to be fairly uniform, a single sample will suffice. If there are marked differences within the area, or you know different areas have been treated differently (i.e. part old garden, part old lawn), then sample each individually. Walk over the area to be sampled and randomly take several trowels full of soil to a depth of three (3) inches, remove any plant material from the sample, and place it in the bucket. Continue this until you have approximately a pint of soil, mix the soil thoroughly, and fill the sample container supplied to you by the laboratory. Seal the container, complete the attached form and ship to the laboratory.
Once the lab has completed the tests you requested, a report will be sent to you along with recommendations as to exactly how much and when to apply the fertilizer.
Now you are ready to visit your local hardware or farm store to buy your fertilizer. The recommendations will likely recommend the use of 10-6-4, 12-4-8, 46-0-0, or a similar looking number. This is the composition of your fertilizer. The first number is the percentage of Nitrogen in the bag, the second is the percentage of Phosphorus, and the last is the percentage of Potassium. Often this is referred to as the N, P & K values.
The other value and recommendation which is found on your soil test report is the pH and the amount of lime which will be required to bring the soil to a slightly acidic condition. Soil acidity or alkalinity is measured by a logarithmic scale known as the pH. Therefore the difference between 6.5 and 6.6 is a significant amount. The scale is represented by 0.0 to 6.9 is acidic, 7.0 is neutral, 7.1 to 14.0 is alkaline. All soils within Maryland and Delaware are acidic by nature. Turf grasses like slightly acidic soils in the range of 6.2 to 6.5. Soils within this range are capable of exchanging the largest amount of nutrients for the plants to use, both the primary nutrients (N, P, & K) and the minor nutrients (like sulfur, boron, manganese, iron, and many others). When the pH becomes very acidic or alkaline, the nutrients are bonded to the soil particles and the plant cannot use them, thus they literally starve to death. Lime therefore is a critical part of the soil amendments.
There are two types of lime which are commonly used for turfgrass, both are ground agricultural limestone, one is calcite lime (high in calcium), the other is dolomitic lime (high in magnesium). Your soil test will recommend which type of lime to use and the quantity necessary. Burnt or Hydrated lime is not recommended for turf grass use.
Ground agricultural limestone comes in three (3) formulations. Pulverized limestone is a very fine powder. It is the cheapest but also the hardest to spread, especially if any wind is blowing. Granular limestone is more the consistency of course sand, however, this formulation is very slow to react as these granules must gradually break down with weathering. Pelletized limestone is the third formulation and that which is most often utilized for turf grasses. Pelletized is actually pulverized lime which has been compressed into small pellets about the size of fertilizer. Pelletized is easily spread, even on breezy days, and readily falls apart to pulverized powder as soon as any moisture is applied.
It is best if lime can be applied and 2-3 weeks later apply the fertilizer. If this time frame is not possible or reasonable, apply the lime, water it into the soil and then apply the fertilizer.
You are now ready to order your sod.
Soil tests should be repeated every 3 years.
Regional Soil Testing Laboratories
|A&L Eastern Agricultural Laboratories7621 Whitepine Road
Richmond, VA 23237
|Agri Analysis, Inc.P.O. Box 483
280 Newport Road
Leola, PA 17540
|Brookside Laboratories, Inc.308 East Main St.
New Knoxville, OH 45871
|Agricultural Analytical Services LaboratoryPennsylvania State University
University Park, PA 16802
|Spectrum Analytic Inc.P.O. Box 639
1087 Jamison Road
Washington Court House, OH 43160
|University of DelawareSoil Testing Program
149 Townsend Hall
Newark, DE 19717-1303
|Waters Agricultural Laboratories, Inc.257 Newton Highway
P.O. Box 382
Camille, GA 31730-0382