Well-Rotted Manure
Amendment
Well-rotted manure is an excellent organic amendment for hungry garden soil. Aged material improves structure, supports soil life and releases nutrients gradually. It is especially useful for vegetable beds, provided it is genuinely well-rotted and applied thoughtfully. Use it as a mulch or soil improver, not as a substitute for good drainage and pH management.
What it is
Well-rotted manure has decomposed for at least a year and should be dark, crumbly and earthy rather than fresh, hot or strongly smelling. It adds organic matter as well as nutrients, helping sandy soil hold moisture and making heavy soil more workable. Different sources vary in richness and bedding content, so it is less predictable than a laboratory-tested feed. Fresh manure can scorch plants, introduce weed seeds and upset growing conditions. There is also a serious risk from aminopyralid weedkiller residues in contaminated manure, which can damage tomatoes, beans and potatoes.
What to do
Buy from a reputable source and ask specifically about aminopyralid weedkiller contamination before using manure on edible crops. Spread well-rotted manure over cleared soil in autumn or spring as a mulch, leaving a small gap around stems and avoiding direct contact with plants. Let worms incorporate it, or lightly mix it into the upper soil when making a new bed. Do not apply fresh manure around crops, and do not apply lime at the same time, as this can waste nitrogen. Use it most generously on hungry ground, but base extra fertiliser decisions on a soil test and crop needs.
Tips
If you suspect contaminated manure, do a small pot test with peas or beans before spreading it widely. Keep records of the source and date. Well-rotted manure is ideal for improving soil but can be too rich for some seedlings and low-fertility plants. Store it covered to reduce nutrient loss in heavy rain.
Well-Rotted Manure: frequently asked questions
What is well-rotted manure?
Well-rotted manure has decomposed for at least a year and should be dark, crumbly and earthy rather than fresh, hot or strongly smelling.
How do I improve well-rotted manure?
Buy from a reputable source and ask specifically about aminopyralid weedkiller contamination before using manure on edible crops.
What are some tips for well-rotted manure?
If you suspect contaminated manure, do a small pot test with peas or beans before spreading it widely.
General guidance for UK gardens and allotments. Page updated 19 Sep 2026.