In the latest segment of Gardentalk, Master Gardener Ed Buyarski suggests using horticultural lime to sweeten or change the acidity level of your garden soil.
Bags of lime are usually found in home improvement or garden outlets around Juneau.
“The soil is normally quite acidic because of the rain we get, plus spruce needles, hemlock needles, muskeg,” Buyarski said. “All of those help to either lower the pH or keep the pH low.”
Buyarski said pH levels affect how plants can take up nutrients from the soil. Neutral pH is 7 and most garden vegetables and flowers will grow well with a pH of 6 to 6.5.
Raspberries, strawberries, potatoes and rhododendrons like low pH or acidic soil, while lilacs and peonies like a soil with a high pH. But Buyarski cautions against adding too much lime or raising your soil’s pH too high.
Wood ashes can also be used as a lime substitute while providing potassium that will strengthen a plant’s stems and stimulate flowering.
Buyarski warns against using slaked lime, which is commonly used in outhouses and sewage systems.
“That will literally burn the plants,” Buyarski said.
You can determine your soil’s pH level by sending samples to a lab. A simple and inexpensive do-it-yourself method includes using pH paper available at pharmacies to test a sample of soil in a jar of distilled water.
