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Is Fresh Manure Better Than Composted? No — Compost It First

Fresh manure burns roots, carries pathogens and weed seed, and locks up nitrogen as it rots. Composting fixes all four problems and costs six months.

By Zakaria 3 min read Save to Pinterest — opens Pinterest in a new tab
A wheelbarrow standing beside a large heap of strawy manure
Photo: sabinevanerp, Pixabay Content License, via Pixabay
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No — compost it first. Fresh manure burns roots, carries pathogens and weed seed, and locks up nitrogen as its bedding rots. Six months to a year of composting fixes all four. The only good use for fresh manure is bare ground in autumn.

Fresh against composted

This table answers the question on its own
FreshComposted
Available nitrogenHigh — and it burnsModerate, steady
PathogensE. coli, salmonella, parasitesKilled in a hot phase
Weed seedViableKilled if hot enough
Nitrogen lock-up from beddingYesNo
HandlingUnpleasant, strong ammoniaDark, crumbly, earthy
Safe around growing plantsNoYes
Only good useBare ground, autumnAnywhere

The one legitimate use for fresh

Spread on a bare bed in autumn and left to weather over winter. It breaks down in place and the bed is usable by spring. That is the traditional application and it works.

What not to do with it

Do not put fresh manure around growing plants, and do not dig it in shortly before sowing. The nitrogen burn and the nitrogen lock-up both arrive exactly when seedlings are least able to cope.

Food safety

Fresh manure can carry E. coli, salmonella and parasites, and these survive in soil for months.

  • 120 days between raw manure and harvesting crops whose edible part touches soil
  • 90 days for crops held clear of it

In practice that means autumn application only. Properly composted manure that has been through a hot phase is a different proposition and is used routinely in vegetable gardens.

Which animal

  • Horse or cow, well rotted — mild, bulky, improves structure as well as feeding. The default.
  • Poultry — much stronger. Use sparingly as a concentrated feed, not as a bulk improver.
  • Pig — rarely recommended domestically, on pathogen grounds.

How rotted it is matters more than which animal

A year-old horse manure heap beats fresh cow manure for every purpose. Judge the material in front of you: dark, crumbly, earthy, nothing recognisable, no ammonia smell at all.

The risk that composting does not fix

Persistent herbicides survive the heap

Used on pasture, they pass through the animal and stay active in the manure. The symptom is distorted, cupped, fern-like growth on tomatoes, beans and potatoes the following season, and there is no cure — the bed is affected for seasons.

Ask the supplier what the pasture was treated with. If unsure, sow beans in a pot of the material first and watch them for three weeks before it goes anywhere near a bed.

Common questions

Is fresh manure better than composted manure?

No, for almost every garden use. Fresh manure is higher in immediately available nitrogen, which sounds like an advantage and is in practice a liability — it burns roots and foliage, it carries pathogens and viable weed seed, and bedding mixed into it draws nitrogen out of the soil as it decomposes. Composting for six months to a year resolves all of those at the cost of some nitrogen, and the result is safer, more pleasant to handle and far more useful.

Can you put fresh manure on a garden?

Only on empty ground well ahead of planting, which is the traditional autumn application. Spread on a bare bed in autumn and left to weather over winter, fresh manure breaks down in place and the bed is usable by spring. What you should not do is put fresh manure around growing plants or dig it in shortly before sowing, because the nitrogen burn and the nitrogen lock-up both hit exactly when seedlings are most vulnerable.

How long does manure take to compost?

Six months as a minimum and a year is safer for a cool domestic heap, less in a hot well-turned one. Poultry manure is the strongest and needs the longest, horse manure with bedding takes a while because of the carbon it brings, and cow manure is milder and quicker. The finished product should be dark, crumbly and earthy-smelling with no recognisable material and no ammonia smell at all.

What is the food safety concern with fresh manure?

Fresh manure can carry E. coli, salmonella and parasites, and these survive in soil for months. The standard guidance is to allow at least 120 days between applying raw manure and harvesting crops whose edible part touches the soil, and 90 days for crops held clear of it, which in practice means autumn application only. Properly composted manure that has been through a hot phase is a different proposition and is routinely used in vegetable gardens.

Which manure is best for a vegetable garden?

Well-rotted horse or cow manure for general use, since both are mild, bulky and improve soil structure as well as feeding. Poultry manure is much stronger and is better used sparingly as a concentrated feed than as a bulk soil improver. Pig manure is rarely recommended for domestic gardens on pathogen grounds. Whatever the source, the deciding factor is how well rotted it is rather than which animal it came from.

What about herbicide contamination?

It is the most serious risk with bought-in manure and it survives composting. Persistent herbicides used on pasture pass through the animal and remain active in the manure, and the symptom is distorted, cupped, fern-like growth on tomatoes, beans and potatoes the following season, with no cure. Ask the supplier what the pasture was treated with, and if you are unsure, test by sowing beans in a pot of the material before using it on a bed.

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