Soil Analyses

The soil results are back from the CT Agricultural Experiment Station. For price of postage ($8) they analyzed 5 composite samples from the various beds around the garden (note: anyone can do this). I was particularly curious about the fill that had been brought in where the house once stood. In the picture below, that's the soil to the right, compared to the nice dark soil on the left from the Butterfly bed.

Of particular interest was pH. I have been working under the assumption that the pH is particularly low here since we have pines and oak all around and because of all the heath species growing. On the other hand, we were adding Sweet Peat to the soil, which has some limestone added. So I wasn't sure how the pH would test out.

The results ranged from 4.6 to 5.6, all acidic as expected, even with the Sweet Peat added. Many native species like acidic soil. But how acidic? I once had a sick rhododendron and sent in some soil for testing. The reply was that the soil was too acidic even for rhododendrons, a species well known for requiring acidic soil. The pH was 3.8 or something ridiculous like that, and I had to add limestone.

I found the chart at right of pH indicator plants in "A Sierra Club Naturalist's Guide to Southern New England" (click to enlarge). Listed plants growing at Eklund prior to planting included Mountain Laurel, Blueberries, Pink Lady Slipper, Canada Mayflower, Partridgeberry, and Interrupted Fern. All but the last one are listed as preferring a pH of 4 to 4.5. Some of the plants we've just recently added, such as Red Trillium, Maidenhair Fern, Asters, Wild Geranium, Baneberry, Columbine, and Sharp-Lobed Hepatica are all listed as prefering a pH of either 5 to 6 or 6 to 8. Therefore our goal will be to bring most of the garden beds up to a pH of 6. The exception will be the heath walk up the stairs and through the pine trees, which will remain very acidic.

As for the fill that was brought in, I'm somewhat suspicious of the reported results, which listed the soil as "sandy loam" even though this soil clumps tightly if you squeeze it and turns into concrete blocks when dry. All the soils were reported to be sandy loam. It is listed as having low-medium organic matter, so a priority would be to add some type of compost.

I'll be calling the Ag Station for clarification about recommended rates of limestone application since they don't specify what pH they are aiming for. The results are shown below (click to enlarge).