Vinegar and Magnolia Trees

Growing Magnolias

• Magnolia trees and shrubs develop shallow root systems, often right at the soil surface, making the plants susceptible to damage to from vehicles or mower blades, or stresses from soil compaction or dryness. For best magnolia plant health, plant them in moist but well-drained acidic soil -- pH 5.5 to 6.5 -- rich in organic matter. Mulching the soil shades the soil and roots to retain moisture and keep the soil and roots cool in the heat of summer. Ample sunlight ensures good branching uniformity and abundant flowering; anywhere from six to 12 hours of sun rays daily suffices.

Determining Soil pH

• White vinegar is one way to determine if your garden soil is acidic or alkaline, albeit imprecise. High pH soils, which are alkaline, often create a fizzing effect if a drop of vinegar is placed atop the soil, if it's rich in calcium. However, no fizz does not mean the soil is acidic. Contact your local cooperative extension office for help in proper and precise testing of soil to determine pH. Only when you know the exact soil pH of the ground around a magnolia can you best approach amending the site to change the soil pH correctly and safely.

Vinegar is an Acid

• Common household white vinegar is also known as acetic acid, with a pH around 3.0, depending on formulation, distillation purity or brand. Pouring vinegar into the soil around a magnolia is a risky, inconsistent and short-term way to lower soil pH. Because vinegar is so acidic, it can burn and kill tiny root hairs. The acid must first be diluted in water, but such a solution has a higher pH value. A vinegar solution poured onto the soil around a magnolia quickly leaches through the soil, and will change the pH, depending on the soil type, amount of soil moisture, subsequent rainfall and amount of organic matter present. Organic-rich soils buffer the vinegar, diminishing its temporary effect of lowering the pH.

Better Solutions

• Changing soil pH is a long-term investment, especially if your natural garden soil's pH isn't already acidic. Apply acid-forming organic matter and mulches to the soil around magnolia trees to help slowly and evenly lower soil pH. Decaying oak leaves, conifer needles and bark and coffee grounds all lower soil pH. Various synthetic fertilizers and additives, especially those containing sulfur or ammonia, are more cost-effective and longer-lasting ways to safely lower garden soil pH around magnolia trees. Always follow product label directions for proper dosages and procedures to obtain the desired soil pH.