Fertilizing Flowers With Lime
Fertilizing products can sometimes be hard to decipher. The amount of available garden products has grown tremendously and it's sometimes hard to know what to use. Lime, also known as calcium carbonate, raises the soil pH which can help boost the availability of certain minerals and nutrients in the soil. It's not an everyday, all-purpose fertilizer, however.
What Lime Does
More often than not, lime is used as a soil amendment as opposed to a fertilizing product. Lime sweetens the soil, or raises the pH to make it more alkaline or closer to neutral. In many cases, liming the soil is ideal for very acidic soils with a pH less than 5.8 to 5.5, although some plants prefer a more acidic soil. While plants vary greatly on preferred pH levels, many plants prefer a slightly acidic to neutral pH ranging from about 6.0 to 7.5.
Fertilizing Properties and pH
Many gardening lime products also contain calcium and magnesium, two micronutrients much needed by plants of all types. Calcium and magnesium are often void or greatly reduced in soil, so the lime helps add these back in. Wet climates often have a leaching factor, where the rain washes away these valuable micronutrients and makes the soil more acidic. Once the liming is complete, the soil pH is raised and these micronutrients are added back in. Soil that is too alkaline or too acidic can greatly reduce the amount of nutrients available to the plants.
Before applying lime to your flower beds, send a soil sample to a reputable lab to be analyzed for soil pH and other factors. Don't lime a soil with a pH of 6.5 or higher as most flowers will thrive without it. Most lime formulations are sold in granulated or powdered forms. These types of amendments and fertilizers are most often sprinkled onto the soil and either raked or watered in. The amount needed will vary greatly depending on how acidic your soil is, what plants your are supplying the lime for and how big the area is. All lime products packaging will include detailed amounts to apply for given situations.
Flowers and pH
Some flowers prefer a slightly more alkaline soil, but most do well in nearly neutral soils. Don't apply lime if your soil is around 5.0 to 5.5 -- or slightly lower -- in an area where you grow rhododendrons (Rhododendron spp.), azaleas (Rhododendron spp.), or hollies (Ilex spp.) and other evergreens, as these plants prefer more acidic soils. Bigleaf hydrangeas (Hydrangea macrophylla cvs.) will change their flower color from blue to pink and numerous colors in between depending on the soil pH. Blue flowers require a soil pH of around 5.0 or less; if you want pinker blooms, adding lime will help the color turn.
With a professional background in gardening, landscapes, pests and natural ecosystems, Jasey Kelly has been sharing her knowledge through writing since 2009 and has served as an expert writer in these fields. Kelly's background also includes childcare, and animal rescue and care.