Bucks County Herald

Elizabeth Ludlow Bowman: Tips for the Compleat Gardener

What is pH to the gardener?

Tradescantia thrives in my alkaline soil.

Finally there are warmer days in the forecast though I hope it doesn’t jump to summer. Later this month should be resplendent with bloom with all that water waiting to swell into life as bloom and leaf.

Here in the Delaware Valley it seems the normal unfoldment of spring has been delayed so nothing much has been up to be frozen. This last week I have noted the early magnolias budding up, which is unfortunate because they do not like freezing nights.

While your soil is slowly warming you can contemplate the pH of your soil and what it means to your success. pH is all about hydrogen ions in the water that is 25 percent of your healthy soil and its presence in the 25 percent of your soil that is air, space between the grains of mineral (45 percent) and rich, food carrying organic matter filling in the last 5 percent. In terms of Hydrogen as its percent goes up the pH goes down with the most ions making the most acidic soil given a value of 1 on a scale that goes to 14, the least acidic (alkaline) with 7 being neutral.

The concentration of H ions affects the availability of nutrients to plant roots. Most plants enjoy a slightly acidic soil 5.5-6.5 and others prefer more alkaline environments. In “ The Lost Art of Reading Nature’s Signs,” Tristan Gooley comments beech, yew and ash prefer alkaline soil and oaks, sycamore, birch and linden tolerate acidity. I would add that my very alkaline soil spouts walnut trees, hackberrys, and sassafras.

It helps to observe what thrives in the conditions you have. I had my soil tested at the local Extension Service but I am not sure that is available anymore. Kits are at every hardware store and I admit I am not very adept at using them.

The blue hydrangea macrophylla can tell the pH – the flowers are deep blue if the soil is acidic and maroon if it is neutral, pinkish if alkaline. Most people don’t like the pink when expecting blue and they work to acidify the soil.

I prefer to plant for the existing conditions rather than try to alter things. Mulching with ground oak leaves, pine needles and peat on a regular basis can encourage a more acid soil as will fertilizing with organic Hollytone but a serious overhaul is difficult.

Learn to like what likes you. Plants have a whole network under the soil that involves more than pH and some take time setting up connections in an unfamiliar soil situation so be patient.

I have noticed over the years that each gardenscape I tend has different violets, both shape and color, and they don’t necessarily take hold if transplanted to a different environment. My alkaline lawn has blue and white, plain violet and over in the shade there are some yellow ones. Once I had the blue speckled ones but don’t see them here anymore.

One of my customers has apricot violets with an elongated flower and a maroon variety and another one has double whites. Take a moment this spring to note the different ones you come across and match them with the pH if you know it.

The alkaline soil will not support rhododendrons or azaleas but spicebush is happy and spreads around freely. Many grasses prefer the more alkaline conditions, which is why lawn maintenance people often apply lime with a spreader.

Be sure you get the appropriate lime product if you are using it. If the magnesium is low, use the dolomitic lime. A spring soil test can reveal what you need to add for garden success.




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