How much worm castings should I use?

For most garden beds, incorporate worm castings at 5–20% by volume into the top few inches of soil. For container plants, mix 10–25% into potting soil. Smaller amounts can be applied as a top dressing during the growing season.

Can worm castings burn plants?

No. Properly matured worm castings are low in soluble salts and release nutrients gradually, making them safe for seedlings, transplants, and established plants.

Are worm castings better than compost?

Worm castings are often more biologically concentrated than traditional compost, typically containing higher microbial activity and more plant-available nutrients.

Do worm castings replace fertilizer?

Worm castings improve soil biology and nutrient availability. They may reduce reliance on synthetic fertilizers but are commonly integrated into a broader soil fertility program.

Healthy Soil - Compost, Vermicast

Garden Mulch: One Thing Every Great Garden Has in Common

By Delta Worms | July 15, 2026

Cherry blossoms framing the Washington Monument during spring bloom in Washington, D.C.

Garden Mulch: Four Famous Gardens One Common Secret. Garden mulch is one thing every great garden has in common. This year I visited several famous gardens—including the U.S. Capitol Rose Garden, Hearst Castle, and the Ronald Reagan Presidential Library—and every one of them used generous layers of mulch. Each garden is unique. Some receive plenty of…

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By Delta Worms | February 2, 2026

If you’re wondering compost vs vermicompost—and which one is right for your garden—you’re not alone. Both improve soil health, but they work in different ways and are best used for different purposes. For SF Bay Area gardeners, understanding the difference between compost and vermicompost can save money, improve plant health, and deliver better soil results.…