Soil is an essential base for plants, providing support and a means for collecting water and nutrients. Problems with plants can indicate a cause related to the surrounding soil. If you have been advised to perform a soil test, or would like to confirm proper conditions in your garden, Cornell Cooperative Extension can perform such tests. We offer a simple pH test in our office, and can help you with a more comprehensive analysis through Cornell University.
A soil test does not explore insect, disease, or many other cultural problems. You may first want to contact our Garden Helpline for help with your problem or submit a plant sample to the Diagnostic Lab.
pH tests
Soil pH is a measure of the concentration of hydrogen ions in soil solution. It is measured on a scale from 0 to 14, with values below 7.0 for acidic soil, and values above 7.0 for basic or alkaline soil. Each unit change is a 10-fold difference; soil with a pH of 5 is is 10 times more acidic than soil with pH of 6. Soil pH levels are affected by mineral deposits, nitrogen fertilizers, and can differ widely over gardens in a region.
Soil pH may decrease a plant’s ability to absorb needed nutrients, and raise levels of other elements to levels toxic to plants. Some plants need a certain range of pH for proper development or coloration. Diagnosis of plant problems often relies on knowing the pH of the neighboring soil. Recommending changes to the soil also requires the gardener to know how much the pH value must be corrected.
Cornell Cooperative Extension, Monroe County, has the facilities to run soil pH tests only. Samples can be brought to the Cornell Cooperative Extension Center at 249 Highland Avenue, and will be conducted in our Diagnostic Lab using a calibrated process.
The cost for the soil pH test is $5.00 per sample. Test results will be mailed to you within 3-5 working days.
Read the guidelines below regarding the proper method of taking a soil sample.
Complete analysis
Complete soil nutrient tests are run at Cornell University. In addition to pH measurement, they report on levels of phosphorus, potassium, calcium, magnesium, aluminum, iron, manganese, zinc, organic matter content, and soluble salts. In addition to the test results, you will receive recommendations for application rates for soil amendments and fertilizer for the plants meant for that area of soil. In order to utilize the services of Agro One in Ithaca, samples must be sent to Agro One in kits which are available from our Monroe County office.
Do not bring or send soil to our office for Cornell University analysis.
Taking samples
When taking a soil sample, gather soil from four or five places at a depth of 4-6 inches for turf, flower or vegetable gardens, or 12-18 inches for trees or shrubs. Mix the soils together in a clean container to form a representative sample of the area for your test. You should collect at least one pint. Separate tests should be taken if you have different sites you want tested. For example, a lawn area and a vegetable garden should be submitted as separate samples. Be sure to label them accordingly. If you have an area that is reacting differently in a lawn, flower garden or vegetable garden, such as a marked difference in growth, then we will need a sample from each area. If you make any additions to the soil such as fertilizer, lime, organic matter, or peat moss, wait 4 weeks or more before bringing in a sample.
If you have any questions about preparing a sample, before coming to the Extension office for a pH test you can contact our Garden Helpline for clarification.