Both compost and manure can bring major benefits to the vegetable garden. But which one is best depends on a number of different considerations. Thinking about these considerations will also help you determine where each is best used.
Compost is best used to create the top layer of planting areas in a no-dig garden, in filling containers, and in mulching directly around annual edible plants. Manure can also be great in creating new growing areas or mulching, but with most manure, it is best to compost before use, and it can often be beneficial to add it only in lower layers, below other bed creation or mulch materials.
When it comes to using compost or manure for the vegetable garden, it is important to understand that it does not have to be either-or. Though both materials have numerous benefits in common, they also have different characteristics. Both can be used together and separately in your vegetable garden. Manure can also be a component in the creation of compost, so that is something to consider.
It is also important to understand that there are different types of compost and different types of manure. Which specific composting techniques you are using and which manures you are considering will often play a role in which is best and where and how exactly these materials are used.
When trying to decide whether compost or manure is the right option for a given situation in your vegetable garden, you need to think about:
- The pros and cons of compost as a material.
- Pros and cons of manure as a material.
- The local availability of both of these materials.
- Which type of compost you are looking at.
- Or which particular type of manure, how fresh it is, and where it came from.
Read on, and by the end of this guide, you should have a much better idea about whether you will use compost, manure, or both in your vegetable garden, and have a much clearer idea about why these materials are useful and how exactly to make use of them where you live.
What are the Benefits of Compost?
One of the major benefits of compost is that it is something that anyone can make at home. Even if you do not have a garden at all, you can usually find a way to recycle food scraps and other compostable household waste in a small-scale system. And the compost you make can be used in creating a potting mix for houseplants or edible crops grown on a sunny windowsill.
If you have a garden, composting is something that naturally happens in nature already. Deciduous trees and other plants that lose their leaves or die back in the fall provide organic matter. That organic matter breaks down, composts, and eventually becomes a rich layer of humus on the soil surface. This humus is, through the agency of bacteria, fungi, earthworms, and other organisms, broken down. The nutrients are returned to the soil.
When we make or use compost, what we are doing is basically shortcutting and taking advantage of this natural process. Rather than just waiting for it to happen on its own, we are placing materials together in such a way that nutrient-rich compost is created.
Because we can make compost on our own, using natural or waste materials, this means that it can cost nothing at all to make. Compost can be made entirely free of charge.
It is relatively easy to learn enough about composting to achieve a mix that is great for:
- Adding fertility. (Though the figures for homemade compost can vary substantially, typical figures for the three key nutrients nitrogen, phosphorus, and potassium are around 0.5% nitrogen, 0.27 % phosphorus, and 0.81 % potassium.) However, it is important to understand that though the finishing compost will be rich in nutrients, a high proportion of these are slow-release and will not be immediately available to your plants. But since the same is true for manures and other organic fertilizers, this is largely irrelevant to this article. Compost adds fertility long term.
- Improving soil structure. When you add finished compost as a mulch in your garden, around garden plants and crops, it is also a way to improve the structure of the soil. It can improve aeration and the amount of water that soil can absorb. It is also great for making the soil more friable, easy to handle, and easy for plant roots to penetrate.
- Increasing soil carbon (and the capacity of soil to sequester (trap) CO2 from the atmosphere). Compost is a form of organic matter. Like other forms of organic matter, it can be added to the soil to boost its capacity to help us in the fight against climate change.
- Boosting microbial activity. By adding good quality compost to your growing areas, improving the soil, you will also be aiding and increasing the numbers of beneficial microbes.
We could simply add mulches of organic materials to our growing areas rather than creating the finished compost first. And this is an important strategy in organic gardening, especially important in gardens that take a no-dig approach. (Which we will discuss more a little later in this article.) Just adding mulches and allowing them to break down on your growing areas is, in essence, composting in place in your garden rather than in a separate heap or bin.
‘Finished’ compost is the name often given to compost that we take from the composting system when there are no (or few) visible remnants of the original plant matter. Using this can bring benefits because it smells sweet and earthy, with no nasty pong. It can look neater and nicer spread around garden beds than other materials that have not reached this stage of decomposition. It can also make a good substrate for the sowing of seeds, whether this is in growing areas in the garden, raised beds, or containers.
What are the Benefits of Manure?
Well-rotted manure can have many of the same benefits as good quality compost. It can also:
- Add fertility.
- Improve soil structure.
- Increase soil carbon.
- And boost microbial activity.
When it comes to fertility, however, it is important to understand that not all manures offer the same levels of nutrients. Some are better for adding low-release fertility to the garden than others. But all can add fertility to some degree.
One added benefit of manure is that it can be even better than compost at boosting microbial life in the soil. This is because it still contains a higher proportion of undigested organic matter than compost – so there is more left for microbes to feed in the long term.
Manure can be great for microbes, and therefore for soil structure and soil health, because it has some readily available nutrients for a quick feed, but also plenty for the microbial life long term.
If you have livestock in your garden or on your homestead or farm, then you can sometimes get manure free of charge. Sometimes, you may be able to pick up manure for free from a local farmer, zoo, or even pet shop in your area. So it is worthwhile asking around to see whether you can find a free source of this valuable garden resource.
What are the Drawbacks of Using Compost?
As we have already mentioned, there are numerous benefits to using compost in your garden. But the degree to which compost can aid you in your gardening efforts can vary considerably depending on the type of compost you choose. When it comes to their nutrient profiles, in particular, some composts are much better than others. Composts can be very variable, which can be one drawback for inexperienced gardeners. That said, even the worst homemade compost is better than none at all.
Another important thing in deciding whether to use manure or compost is that, as mentioned above, compost has less undigested organic matter to feed the microbial life in your soil. Some of the digestion by microbes has already taken place in your composting system.
If you do not make your own compost at home, it is worth noting that some bought composts are terrible for the environment. Peat-based composts, for example, which are commonly found online and in stores and garden centers, are not sustainable or eco-friendly choices. Peat-based composts contribute to the destruction of peat bogs, which are vital carbon sinks. We need to stop using peat in gardening and move to more sustainable alternatives that do not lead to ecosystem destruction or degradation.
Another thing to note is that when you buy compost in plastic, this also takes a massive environmental toll. Plastic packaging also poses a problem at the end of its useful life. Compost bags are not usually recyclable and contribute to our global plastic waste crisis.
These are just a couple more reasons why, if you plan on using compost in your garden, it is by far the best option to make your own.
What are the Drawbacks of Using Manure?
As mentioned above, manure can be free if you keep animals at home or can find a free source in your vicinity. At other times, however, you may have to pay for manure to use in your garden. It all depends on where you live and what options are available in your area.
The most important thing to remember about using manure is that most manures must be composted/ well-rotted before use. You usually cannot just take fresh manure and spread it in your garden.
This is because manure can contain pathogens that can pose a risk to human health. And also because they can have a high nitrogen content, which can, when not well-rotted, ‘burn’ plants. The exception to this is rabbit manure, which can be used more directly in the garden.
Overuse of fresh manures can cause excessive nitrogen levels, which can pollute the soil and waterways and even create ‘dead zones.’ This is not usually a problem when manure is composted/ well-rotted and used at a garden scale. But if you are thinking of keeping livestock for manure, then this is something to consider. How much manure animals generate is one of the factors that will determine how many animals you should keep on a given area of land.
Some manures might be contaminated with medicines (such as antibiotics) or chemicals if the manure came from livestock not managed within an organic system. This can be a concern – especially if you are planning on using manures around edible crops.
Some manures can also contain weed seeds that may pose a problem when they pop up in your garden beds. But whether or not this is a problem will depend, of course, upon the source.
Of course, if you are dealing with fresh manure, there is also the issue of the smell. Fresh manure can truly stink. But making sure that it is well rotted before use usually combats the worst of the problem.
When trying to decide whether to use compost or manure in a given situation, one key consideration is likely to be how easy it is for you to get hold of these materials. As mentioned above, one of the main benefits of compost over manure is that anyone can relatively easily make their own at home.
Buying in compost can be expensive. And we have already spoken about many of the benefits of choosing to make it yourself at home. If you do decide that you would like to buy some in, however (perhaps because you want to create new growing areas and do not want to wait for homemade compost to be ready), then which you buy will likely be determined by which you can easily get your hands on.
As mentioned above, as an eco-friendly and sustainable gardener, you should try to avoid purchasing peat-based composts wherever possible. Consider coir, bracken, or sheep’s wool-based alternatives, for example.
When filling a few raised beds, many gardeners may head straight out to a garden center and purchase bags of potting soil/ compost. But filling your raised beds with bags of bought material can be expensive. And it is important to realize that you do not need to fill a bed entirely with compost. You just need compost (or something similar like loam or leaf mold) for the top. (We’ll discuss how to make new beds using just a little compost and other organic materials later in this article.)
We’ve already spoken briefly about how you might already have access to manure if you keep livestock. You may also have a source of manure to use in your garden if you have herbivorous pets like rabbits, guinea pigs, hamsters, gerbils, etc.
If you do not have your own source of manure from livestock or pets, you should:
- Speak with local farmers or homesteaders to see if they have manure to spare.
- Visit a local pet shop to talk about the potential for you to take manure off their hands.
- Speak to a local wildlife center, petting zoo, or zoo to ask whether they have any manure you could take.
- Purchase manure commercially.
But wherever you source the manure, make sure that you know where it came from and that it is not contaminated and will be safe for you to use. And do remember that most manures need to be well-rotted or composted before use in your garden. In some areas, especially urban areas, it would be better to buy or source manure that has already been well-rotted as neighbors may not be best pleased by the smells if you compost it on a larger scale in your garden.
Types of Compost
The characteristics of compost are largely dictated by the materials that have gone into them and the methods that were used.
A typical home composting system will contain a wide range of ‘brown’ carbon-rich and ‘green’ nitrogen-rich materials. It should not only contain a good NPK balance for long-term fertility but also contain a range of micro-nutrients that are also necessary for good plant growth.
Adding particular ingredients to the compost can speed up decomposition and may sometimes add specific nutrients that may be lacking in your soil. (It is important to note, however, that neither compost nor manure is a ‘quick fit’ when it comes to nutrient deficiencies. The gains are all much longer term. So if a particular plant is showing signs of nutrient deficiency, an organic liquid feed or liquid additives are more likely to help.)
Home composting is usually an aerobic process. Organic materials are broken down in the presence of oxygen. You can, as mentioned above, compost in place. You can also set up a typical cold composting system or a hot composting system.
One interesting thing to note is that there is one form of composting that combines compost AND manure – vermicomposting.
In vermicomposting, special worms are housed in a wormery and fed with organic materials. Just as in other composting systems, brown and green materials are added. Worms aerate the compost as they wriggle their way through it, and through this aeration, speed up the decomposition process. As they eat their way through, they also generate worm ‘castings’ – worm manure. The finished product, when bins are emptied, is a mix of normal compost and worm manure. And can be excellent for use in your vegetable garden.
Different Animal Manures
A number of different manures can be used in a garden. For example, in certain situations, it can be a good idea to use the manure from::
- Chickens (or other types of poultry such as ducks or geese)
- Other birds (pigeons/doves etc.)
- Rabbits or other herbivorous pets such as guinea pigs, hamsters, gerbils, etc.
- Alpaca/ llamas
- Certain exotic zoo animals (non-meat-eating).
One important thing to note, however, is that certain manures – such as human feces and the manure of carnivorous pets such as cats and dogs – require specialist composting. They should not be applied to kitchen garden areas unless you have expertise in this arena in order to compost and use them safely.
One vital thing to understand is that different manures are different in terms of nutrient profiles and characteristics.
Manure from chickens, for example, is especially high in nitrogen.
Manures from cows and horses are also quite high in nutrients. But lower in nitrogen than chicken manure. Horse manure can contain a lot of weed seeds, so this is something to consider.
Sheep, goat, and alpaca/llama manures take a bit less time to compost. Manures from these animals are usually a bit more balanced. They contain more phosphorus and potassium than a lot of other types of manure. They also have a less unpleasant odor than those mentioned above.
Pig manures can have lots of pathogens that can also infect humans. So it is particularly important to compost these well and for a reasonable length of time.
One manure that can be added to your garden without composting it first is rabbit manure. Rabbit manure (and some other similar manures) is especially useful for the garden. It contains a high level of nutrients but will not burn plants with excessive nitrogen content.
Using Compost in the Vegetable Garden
Traditionally, compost was dug typically dug into garden beds. But in an organic garden, it is generally best to take a ‘no dig’ approach.
Digging and tilling can damage the fragile soil web upon which we depend. In a no-dig garden, we try to leave the soil as undisturbed as possible. This means that when making new growing areas and when tending our gardens, we take steps to protect the soil surface and to disturb it as little as we can.
Since a finished homemade compost is typically light, friable, and more broken down than other organic matter, it can be good for topping new beds or growing areas. It can also be used annually as a mulch. As mentioned above, compost does not need to be used to fill an entire bed. You can consider using no-dig approaches such as creating ‘lasagna gardens,’ ‘hugelkultur mounds,’ or straw bale gardens.
In a lasagna garden, a layer of cardboard is covered with a carbon-rich material such as straw, wood chips, dried leaves, etc. Then a layer of nitrogen-rich materials such as grass clippings and other green leafy material is added. These layers are built up and compressed gently until they reach the required height, then the bed need only be topped with a thin layer of compost into which you can plant or sow.
Hugelkultur is similar, but mounds rather than flatbeds are created. And a skeleton of rotting wood forms the heart of the structure, below the other layers of organic materials.
In a straw bale garden, the bales themselves are used as raised beds. These are inoculated with a nitrogen feed to speed decomposition and topped with compost pockets into which plants are placed.
Over time, the materials in layered beds break down. But as they do, new mulches are added on top, and the soil is gradually built and improved over time. Compost can be added as a stand-alone mulch in your vegetable garden or added on top of other organic matter.
Of course, compost can also be used in filling containers and pots. One way to make a mix for seed sowing is:
1/3 homemade compost
1/3 leaf mold
1/3 loam/ friable garden soil.
Though if you worry about weeds, there are also plenty of soilless mixes you can make using compost and other materials.
You can also add compost to water to make a liquid plant feed.
Using Manure in the Vegetable Plot
You can use composted manure, usually the same way as other composted material in your growing areas.
Typically, gardeners dig well-composted manure into garden beds during the autumn or in the spring. But no-dig gardening means aiming to not disturb the soil too much. We avoid digging whenever we can to avoid damaging the precious and fragile soil web. When we leave it undisturbed, this complex web, with all its diverse organisms, can work as it should.
In a no-dig garden, you should top dress garden beds early in spring with well-composted manure (or rabbit manure). You should add around 5-8cm layer of this material in depth.
If you are creating new growth areas, it might be better, for most forms of manure, to use these in creating the lower layers of the bed so that they are buried. This means that the weed issues for certain manures will be less important. And you will not have to worry about coming into contact with the well-rotted manure when planting and sowing.
As with compost, you can also utilize well-rotted manure in order to create a liquid plant feed. Just add composted manure to a bucket of water. Strain it, and you can then use it around plants that require a well-balanced, nitrogen-rich feed.
Both compost and manure can be very useful things in your vegetable garden.