Can You Apply Too Much Compost Tea to Your Plants?

The Basics

• It's impossible for your garden to overdose on compost tea. Because it's a liquid, water rapidly washes it away -- and that means you're more likely to have problems keeping it working in your garden than applying too much. After rainfall or a regular watering in your garden, you'll usually need to reapply compost tea to compensate for natural leaching. It's also much weaker than fertilizer, without the salt levels that cause fertilizer to burn plants when used in excess.

Types of Compost Tea

• Compost tea comes in two main types: fungal and bacterial. The type you apply to your garden depends on the plants you're growing. Typically, woody plants, such as trees, prefer fungal-dominant tea, while green plants such as grasses, annuals and vegetables appreciate bacterial-dominant tea. However, most compost tea contains both fungi and bacteria, and applying the opposite kind from what's preferred for a specific plant won't harm it.

Soil Application

• When you apply compost tea to soil, thoroughly drench the dirt to ensure it flushes over the entire root zone. A medium-sized plant usually needs about 2 cups of tea mixed with more water, and you can dilute the tea up to a tea-to-water ratio of 1:3 if you're dosing a sprawling area. One or two doses a month throughout the growing season should suffice to sustain plants and lawns, but you're free to add more whenever you like -- especially if rain washes the compost tea away.

Foliar Spray

• Another way to apply compost tea is as a foliar spray. A fine misting to coat leaves is typically enough to supply plants with the nutrients they need. However, unlike soil applications, foliar applications are subject to UV rays destroying the beneficial microbes; to avoid this problem, use foliar spray in the evening or early morning.

Diluting Compost Tea

• It's never necessary to dilute compost tea except to cover a larger area. However, this also means a reduced concentration of organisms and, with foliar spray, less effective coverage. Because you can't apply too much, it's often better to over-apply rather than under-apply, and many plants need massive amounts of tea to reap its rewards. For instance, 1 acre of trees that are 25 feet tall requires 25 gallons of undiluted compost tea. It's especially vital to ensure you apply enough if your plants are diseased, because under-application or too much dilution can prevent the tea from improving plant health in the long run.