The Dirt on Ph

Dear Farm,
A friend of mine was telling me I should have the pH of my soil tested. How necessary is this to have a healthy garden?

Backyard Gardener in Emmaus PA

Dear Backyard Gardener,
Good question! Let's start with explaining what pH is: simply put, it is a system of measuring the acidity or alkalinity of something. Here is a handy chart courtesy of Boulder's Water Monitoring authority:




In soil, the pH directly effects how easily plants can absorb nutrients. Nearly all plants require soil that is slightly acidic. Anything above a pH of 6.5 makes it difficult for the plant to get what it needs to survive (with the exception of some trees).

Some plants love acidity and thrive with a lower pH. Azaleas, Rhododendrons, Laurels, Blueberries, and Rasperries all do better eating the brown acid (couldn't resist!). On our side of the Blue Mountain here in Pennsylvania, it is easy to determine our soil is acidic, since these plants are very common throughout the forest. For an excellent listing of which plants prefer which acidity, check out the Colorado State Cooperative Extension Office's list.


As far as having your own soil tested, it can be a handy thing to know, but if you are adding a good amount of compost to your soil each year and your plants are all doing well, feel free to follow the "If it ain't broke, don't fix it" motto.

If your plants are not doing a nice as you'd like them to, having the soil tested might be just the information you need to get them really thriving. There are several testers on the market. We really have no preference for one over another. This Electronic Soil Tester seems like quite a fancy doo-dad. Your local Cooperative Extension Office offers low-priced soil testing as well as great advice targeted to your area. The Lehigh County office's website takes a bit of time to navigate, so here is the direct link to the soil test.

If it is determined that your soil is too acid, pulverized limestone can help raise the pH level. If your soil is too alkaline, adding large amounts of rich organic matter can help to lower it. This is an area where your Cooperative Extension Office can be helpful in suggesting the proper amounts of soil ammendments for you. Good Luck!

If you have a question for the farm, email us at wegrowveggies@msn.com with "Ask the Farm" in the subject line.