The Best Soil Types for Lemon Balm

Soil pH

• A soil test determines the acidity of your garden soil by providing the soil pH measurement. Lemon balm prefers a soil with a pH between 6.0 and 7.0. Higher or lower pH levels inhibit the plant's ability to take in nutrients, leading to weak growth and eventual death. Beds that previously grew vegetables or herbs usually fall within the correct pH range but new beds require testing. The soil test details any amendments necessary to bring the pH to the correct level. Lime is the typical amendment necessary in most beds, but soils with high alkalinity may require a sulfur amendment.

Soil Quality

• Lemon balm grows best in humus-rich soil that drains well without drying out too quickly. Beds containing a lot of organic matter provide optimum moisture qualities but poorer soils improve with the addition of a compost amendment. Low-lying beds that collect irrigation or rain water cause the perennial roots of the lemon balm to rot. Building a raised bed in these areas helps eliminate most standing water concerns. Sandy beds may dry out too quickly, which either necessitates more frequent watering or the addition of compost to the soil to help improve moisture retention.

Nutrients

• Annual fertilization helps replenish the nutrients in the soil. Lemon balm doesn't require high fertility levels but it grows and produces better with some light fertilization. A light application of a balanced slow-release fertilizer in spring and again after harvest provides the plants the nutrients they need to produce new, healthy growth each year. Applications at half the package-recommended rate for your bed size provide suitable nutrients. Over-fertilization inhibits the development of oils in the lemon balm foliage, which compromises the flavor of the herb.

Container Soils

• Container-grown lemon balm plants do best in a soil-less planting mixture that contains peat, vermiculite, perlite and other non-soil components. Garden soil compacts quickly in containers, suffocating the roots and eventually killing the plant. Soil-less mixtures provide optimum drainage and soil aeration, leading to healthier growth. The soil in lemon balm containers requires monthly fertilization with a soluble fertilizer during the growing season, as soil-less potting mixes contain few natural nutrients.