Using Aged Manure
Amendment
Aged manure is animal manure that has been allowed to sit and break down over time before it is added to a garden. Many US home gardeners use it to build soil and recycle a common on-farm and backyard material. Understanding what "aged" means and how to work it into beds helps you use it well.
What it is
Aged manure is manure from animals such as cows, horses, chickens, or rabbits that has broken down over weeks or months, either on its own or as part of a compost pile. As it ages it tends to lose its strong odor, darken in color, and become more crumbly and uniform than fresh manure. It adds organic matter that can improve soil structure, help sandy soils hold moisture, and help clay soils loosen and drain. It also returns a range of plant nutrients to the soil, though the exact content varies widely by animal, bedding, diet, and how the material was stored.
What to do
Work well-aged or composted manure into the top few inches of a bed and mix it evenly with the existing soil, or spread it as a surface layer that you allow to settle in. Fresh manure is better composted or aged first rather than placed directly around growing plants, since it can be strong and uneven. Many gardeners prefer to add it in fall or well ahead of planting so it has time to blend into the soil. For edible crops, follow the timing guidance your local Cooperative Extension provides for using manure-based amendments in vegetable gardens.
Tips
Because manure content varies so much from source to source, have your soil tested before adding large amounts, and let your local Cooperative Extension help you interpret the results and decide on the right rate for your beds. Try to know the source of your manure and whether the animals may have grazed on treated pasture, since some residues can persist and affect sensitive plants. Store any extra material where it stays covered and away from wells, streams, and runoff paths.
General guidance for US gardens. For specific nutrient, pH, and amendment rates, have your soil tested through your local Cooperative Extension office. Page updated Aug 4, 2026.