Q. I’m wondering how I might check and adjust the soil pH to make it more acidic for my Azaleas, Rhododendrons and ferns. Will applying an acid fertilizer be sufficient or should I use something more specific?
A. A pH scale is used to determine the acidity or alkalinity of a soil. With seven point zero being neutral, any reading below seven is acid or above which is alkaline. Although you can have it done professionally, it is a task that most gardeners can do themselves, as the pH kits are available at your favorite garden center. When testing your soil, here are a few things to remember. The soil sample should be taken from an inch or two below the soil surface and allowed to dry out if wet. You don’t want to touch the sample with your hands or fingers so use a trowel or better yet a plastic spoon. Several samples from different areas are suggested. All the data is then averaged together for a single reading. The winter rains can mask the true pH so it’s suggested to do a follow up test in late September or early October to measure the effect of your municipal water supply on your soil. Azaleas, Blueberries and Rhododendrons thrive in our area with a soil pH of around 5.5 to 6.0. Camellias, ferns and other shade plants have varied degrees of tolerances. Once the pH level has been established you can then add an acidifier. The principle acidifiers are Aluminum Sulfate, and Soil Sulfur, not to be confused with dusting sulfur. The amount of the acidifier necessary to lower the pH is found in a table on the packaging. Coffee grounds are also viable as an acidifier but it is best used to them to maintain the pH level. There are no stats on the amount of coffee grounds that have to be applied to affect the pH level. The following website is an excellent tutorial on how to do a pH test with a kit widely available at your favorite garden center.
http://www.gardengatemagazine.com/extras/54soiltesting.php
Another option is to use a pH meter also available at your favorite garden center.
Q. Perhaps it’s a silly question but can one add the shells from sunflower seeds or peanut husks to the soil?
A. While there are no silly questions, some are more unique than others. Why not, add sunflower and peanut shells to the soil and or a compost pile. They are just as good a source of organic matter as the more traditional soil amendments. The biggest risk they present is the salt residue if they’re pre-salted. To minimize this risk I’d pre-wash the shells by placing them in a bucket of water, rinsing them a couple of times. This should do the trick. Once they have dried out, they’re placed in a plastic bag and crushed with a rolling pin. A wine bottle is an excellent alternative rolling pin. The crushing is suggested as the smaller particles decompose quicker than larger ones.
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