CHATTER Newsletter - Soil Samples for pH Tests

Soil Sampling

You can bring up to one sample from your garden to be tested.

Please keep the following in mind when bringing samples to the meeting:
  • Keep the samples small:  one (1) cup of soil is sufficient
  • Place the soil in a plastic zip lock bag with the following information:
  • Label the outside of the bag with the following information
    • PRINT this information
    • your name and telephone number
    • location in the yard from which the sample was taken
  • If your sample is not tested during the meeting the results will be given to you by telephone when they are ready.

Collecting Soil Sample

It is important to test the soil that the rose roots are actually in contact with. Therefore, begin by selecting a site in the rose garden, preferably near the center where we could expect it to represent the average for the bed. Scrape away any mulch or organic material that may be covering the bed. With a small trowel, remove a pie shaped section with the tip of the pie representing the soil that is about six inches (4" - 8") below the surface. Take a 3-tablespoon sample from the soil at the bottom of the pie wedge and put it in the bag. Label the bag with your name, telephone number and the location of where you obtained it if you intend to bring more than one sample.

Soil Sampling

Testing for pH is necessary to determine how much lime to use on your soil to adjust the pH to the 6.6 - 7.0 range which is optimum for rose growth. When the pH is too low, as it often is in the Portland area, the fertilizer added to the soil is not as effective as it could be. The chemical reactions that occur in an acid soil bind the nutrients in the soil as inorganic compounds rather than allowing them to be available to the plant.
A complete soil test would reveal the fertilizer elements you may have too little or too much of available in your soil. We are not offering this one, but if you have it done, the information you get from a complete soil test can be used to determine what type and how much fertilizer you will need to use during the upcoming growing season.