Soil Testing Office, Instructions, Windsor

Valley Laboratory

Questions or requests for information can be made by phone, fax, email, or in person. Diane Riddle is responsible for the office. The office is located in Room 4 at Valley Laboratory in Windsor. Office hours and phone access is Monday-Friday, 8:30 a.m. - 4:30 p.m.

For more information:
Attention:  Diane Riddle
Valley Laboratory
The Connecticut Agricultural Experiment Station
153 Cook Hill Road
Box 248
Windsor, CT 06095-0248

Phone: (860) 683-4977 ext. 2
Fax: (860) 683-4987

Click below to view the various sections of this soil information page
Submitting Soil Sample for Fertility Analysis
History of the Morgan Soil Test
Tests Performed
Correcting Deficiencies or Excesses

Submitting Soil Samples for Fertility Analysis

  1. For each area to be tested, submit representative samples by removing 10–20 narrow slices or cores of soil (use a garden trowel or other sampling device). Mix slices or cores together thoroughly in a bucket or other container and place 1–2 cups of the mixture in a sealable, waterproof bag or container (paper bags or cups and glass are discouraged). If more than one area are sampled, repeat this procedure for each area. If samples are wet let them dry before packaging.
  2. Sampling depths. For lawns, Christmas tree plantations and field grown woody plants, sample the upper 0-4 inches of soil. For gardens, landscape plantings and commercial row crop production fields, sample the upper 0-6 inches of soil. For plants grown in containers, sample the entire depth of the potting media.
  3. Label each sample with an identifying name and location or crop to insure that results are recognizable.
  4. Send or bring samples according to the instructions listed above.
  5. For unusual or difficult problem areas, contact the Soil Test Laboratory at (860)-683-4977 before sampling.

Deliver or mail soil samples to:
The Connecticut Agricultural Experiment Station
Valley Laboratory
Soil Testing
153 Cook Hill Road
Box 248
Windsor, CT 06095-0248

History of the Morgan Soil Test More than fifty years ago, M.F. Morgan of this Station added immeasurably to our knowledge of the relationships between plants and soils. He devised a soil test that could estimate deficiencies or excesses of plant nutrients. Called the "Morgan Soil Test," it became the world’s first widely accepted method for quickly estimating soil fertility.

Today, soil testing extends our knowledge of Connecticut soils and helps farmers, gardeners, and homeowners learn how to improve soil fertility in an environmentally responsible manner.

Tests Performed Soil samples are tested for texture, organic matter, pH, nitrate nitrogen, ammonium nitrogen, phosphorus, potassium, calcium, and magnesium. Except for pH and texture, all results are expressed as high, medium, and low. A nutrient is classified as excessive when it is likely to damage plants. If necessary, we can perform tests for salts, percent organic matter, and particle size.

Texture: Texture of the soil influences the amount of water and nutrients a soil can hold. Sands (S), loamy sands (LS), and Sandy loams (SL) require more frequent watering during droughts and lose nutrients more readily by leaching than do fine sandy loams (FSL) and loams (L). Silt loams (SIL), silty clay loams (SICL) and clay loams (CL) retain moisture for longer periods of time and lessen the leaching of nutrients.

pH: Soil pH affects the availability of plant nutrients. When interpreted with texture and organic matter, pH indicates the lime needs of the soil. pH is expressed in pH units. Acidic soils have a pH below 7.0 and alkaline soils have a pH above 7.0. Most plants grow best at a soil pH between 6.0 and 7.0. A small number of plants such as azalea, rhododendron, and blueberries prefer a soil pH between 4.5 and 5.5.

Nitrate and Ammonium Nitrogen tests indicate nitrogen immediately available to plants, but do not necessarily indicate how much nitrogen may later be liberated from the soil. Thus proper interpretation of these results is essential. Nitrogen favors leaf growth and imparts a deep green color to plant foliage. Excessive ammonium nitrogen can damage plants and is often an indication of overfertilization. Very high nitrate nitrogen levels may increase the risk of nitrate contamination of surface and groundwater.

Phosphorus binds strongly in soil and is often unavailable to plants. Annual applications of phosphorus fertilizer are usually necessary. Deficiencies in phosphorus are often indicated by poor root, fruit or vegetable growth and a purpling of the older leaves. Excessive phosphorus can move to rivers, ponds and lakes and promote the growth of algae and weeds.

Potassium is supplied by the clay and organic matter in native soil, however, improved plant growth is often obtained by the addition of
potassium fertilizer. Sufficient potassium is thought to improve flowering, disease resistance, cold hardiness and drought survival. Potassium leaches readily from soil.

Calcium in soil is readily revealed by our test. Limestone can correct a calcium deficiency, and will also neutralize soil acidity. When the pH is high and the calcium level is low gypsum (calcium sulfate) is often suggested.

Magnesium tests identify soils where magnesium treatments such as dolomitic limestone or epsom salts (magnesium sulfate) are likely to be beneficial. A Low magnesium level is usually associated with acidic soil.

Other Elements. Plants require small amounts of other elements including iron, copper, zinc, sulfur, and boron. Soil tests have been devised for these elements but they are neither quick nor infallible. Iron, copper, and zinc are affected by soil acidity and we can usually infer their availability from the pH test. There is rarely a deficiency of sulfur, while boron deficiency is usually encountered only where soils have a pH over 7.0. Measurements of soluble salts are sometimes reported on our tests. Overfertilization, salt water, or road salt are often sources of salt.

Correcting Deficiencies or Excesses Based on the soil test, applications of limestone, fertilizer and compost or manure are often suggested. The proper time for application of
each amendment is usually stated. Organic amendments are suggested when requested.

Liming materials generally include most compounds used to raise the pH of a soil. Dolomitic limestone is the most common form of liming material sold in Connecticut. It contains both calcium and magnesium carbonates. Quality limestone is finely ground to permit rapid release in the soil.

Hydrated lime reacts more rapidly but is somewhat caustic and may damage plants. If it is used, it should be thoroughly worked into the soil at about three-fourths the rate suggested for limestone. Burned lime or quicklime is very caustic and is rarely used.

The principal plant nutrients in mixed fertilizers are nitrogen (N), phosphorus (P), and potassium (K). Although they may be present in various forms, Connecticut law requires that the formula on the container be expressed as the percent of nitrogen (N), phosphoric acid (P205), and potash (K20). It is always in this order: thus a 5-10-5 mixture would contain 5 pounds of N, 10 pounds of P205, and 5 pounds of K20 in each 100 pounds of fertilizer.

Trace elements are sometimes added to fertilizers. The desirable range between element toxicity and deficiency is usually narrow, so such mixtures may harm plants if used in excess.

If manure is applied, less commercial fertilizer may be required. Cow manure is low in nutrients and has a typical analysis of 0.5-0.25-0.5. About 10 tons per acre (1 cubic yard per 1000 square feet) may be applied. Fresh chicken manure contains more nitrogen than cow manure, particularly in the ammonia form. If the plants to be grown are sensitive to ammonia, fresh manure should be aged, composted or worked into the soil well in advance of planting.

Other nitrogenous wastes such as municipal and industrial composts may be used. Application rates for composts are generally based on their nitrogen content, which is similar to animal manures. Use of composted sewage sludge may require approval of the Connecticut Department of Environmental Protection.