Compost Pile Temperature and Weed Seed Survival

Heat Is the Only Reliable Killer

Weed seeds die at 140°F sustained for 3 days. Use a long-stem compost thermometer to check center temperature.

Piles smaller than 4' × 4' × 4' rarely reach lethal temperatures.

Seeds won't die quickly but will decompose over several months. Keep pile moist, turn regularly, and accept slower seed destruction.

About Gardening: Eliminating Grass in a Creeping Juniper Border; Composting Basics: Building and Maintaining a Pile; Identifying and Controlling Invasive Fine-Bladed Grass in Coastal California; Sand Topdressing: Benefits, Compost Blends, and Compost Tea Reality; Grass Clippings: Nature's Free Nitrogen—Don't Bag Them; Composting Grass Clippings: Turn Lawn Waste into Garden Gold; Using Grass Clippings as Mulch and Soil Builder; Grass Clippings as Vegetable Garden Mulch: Safe if Herbicide-Free; Using Grass Clippings as Mulch in the Vegetable Garden: Pros and Cons; Using Grass Clippings Treated with Weed Killer as Mulch

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