What to Use on the Compost Heap

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Raw veggies, grass and garden clippings are a great place to start with a compost bin.
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In this compost bin, the wood should be store separately as it takes longer to break down.
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“Organic Gardening Techniques” by Nick Hamilton, is filled with expert gardening tips to help gardeners of all skill levels.

Organic Gardening Techniques(Companion House Books, 2018) by Nick Hamilton, offers gardeners insight for planting and growing various fruits, vegetable and herbs. Find your gardening niche with help from Hamilton and see how your gardens can blossom. This excerpt can be located in Chapter 5, “Produce Storage and Off-Season Maintenance.”

What to Use on the Compost Heap

There are many materials that can be used in an organic compost heap. Some are fairly obvious; others are not.

Garden Waste and Old Cut Flowers

All leaves, dead flowers, and the like that you remove or that fall naturally from vegetables, fruits, and plants—even diseased and pest-infected material—can be composted. The heat generated in most compost heaps, and certainly in enclosed heaps, has been found to be high enough to kill most diseases, spores, pests, and eggs. It is important to shred this type of garden waste first because it usually contains high levels of lignin that bacteria find hard to break down and thus will be slower to rot.

Grass Clippings

Most gardeners generate a good supply of grass clippings throughout the growing season, so it is a good thing that the clippings serve as an excellent activator for the soil heap. Put thin layers onto the heap regularly; layers that are too thick will cause anaerobic bacteria to work, creating a smelly and slimy mess that rots slowly. You can compost flowers, leaves, and other waste from your garden.

Raw Kitchen Vegetable Scraps

After lawn clippings, raw vegetable scraps are probably the most popular materials for the compost bin.

Rhubarb Leaves

The leaves of this plant are poisonous, so eat the stems and put the leaves onto the compost heap. Although the leaves are poisonous to us, they are perfectly safe to compost.

Garden Prunings and Hedge Clippings

It is possible to put the softer material straight on the heap, although it is generally better to shred it first. Woodier stems will compost much more slowly because they contain lignin, so you will definitely need to shred them first. Be aware of conifers and evergreens because larger quantities of them tend to make the compost more acidic. Newspaper and Cardboard

Colored ink or colored cardboard can contain chemicals that organic gardeners do not want on their productive areas, so use only white paper with black ink or noncolored Vegetable trimmings and eggshells are among the kitchen waste that you can compost cardboard. Although they are usable for compost, newspaper and cardboard do not really add anything to the heap and are probably better used for other purposes in the garden, such as being put into the bean trench or made into sweet pea tubes.

Brassica Stems

The stems of all brassicas can go onto the compost heap, but they are thick, fibrous, and full of lignin. Shredding them first is the obvious answer, but if you don’t have access to a shredder, then break up the stems with a hammer—which can serve as an excellent stress buster!

Wood Ash

If you have a wood-burning stove, you can add all of the ash produced to the heap; however, if the ash contains material from a coal and wood fire, be warned that too much will acidify the heap. The only downside of this material is that you generate it mostly during the winter and use it primarily in the summer, so you would need to store it in bags until you are ready to put it on the heap. Wood ash will provide the heap with a good source of potassium. Wood ash is also a fantastic barrier against ground-traveling slugs and snails. I know that a lot of people use crushed eggshells, coarse gravel, and coffee grounds, but they just make the slugs’/snails’ journey uncomfortable. Wood ash actually prevents them from getting to your valuable plants because it absorbs the slime they use to travel on, effectively removing their mode of transport. It is important to use pure wood ash, no coal added, and apply it in a 4–6-inch (10–15-cm) band. You will need to reapply it after any rain (light or heavy) or heavy dew because it will become crusted and, therefore, ineffective. This is a great use for the by-product of a wood-burning stove. The added bonus is that it also has a good potash level, which helps slug/snail-susceptible plants, such as delphiniums, lupins, and dicentra, flower.

Blood Meal

Blood meal, or dried blood, is available from garden centers and home-improvement stores, generally in powder form. It contains readily available nitrogen and is an excellent activator for aerobic bacteria. It adds no bulk to the heap, but if your composting seems to be going slowly, you can sprinkle on some blood meal to give the bacteria a boost. Natural Fabrics, Feathers, and Human and Animal Hair

All of these materials contain available nitrogen and are activators, but they are slow to break down. Therefore, before adding any of these materials to the heap, cut them into small pieces or strips so that they can be more easily broken down.


This is a rampant plant that is commonly found in woodlands. Before collecting bracken, make sure that the woods are not privately owned and that it is OK for you to collect bracken from where you find it. It is an excellent bulking-up material for a compost heap, although it needs to be shredded first due to its high lignin content.

Hay and Straw

Hay is much better than straw as a compost material because it contains more nutrients and rots down quicker; both need to be well moistened before adding to the heap. Unless there is a very generous farmer close by, hay and straw would usually have to be bought, making them an expensive option.

Comfrey Leaves (Symphytum officinale)

I have a small patch of comfrey in my community garden area and find it invaluable. I cut the leaves regularly, which keeps the plants under control. Added to the compost heap, they work as activators and as valuable sources of potassium and phosphate. You can also put the leaves into water to create liquid feed. Every productive garden should have at least one comfrey plant.

Tree Leaves

These are not the best material to add to a compost heap that needs to be turned around quickly. Tree leaves are usually very slow to rot because they comprise mainly lignin and will take a minimum of a year, but usually two or three years, to decompose completely. If they are rotted down in plastic bags or in their own specially-built leaf bin, they make an excellent seed or potting soil.

Potato Stems Once you’ve harvested the potatoes, you can put the stems onto the compost heap. If there has been blight on a particular variety, be sure to compost the haulms from these plants only on a heap in an enclosed bin because the enclosure will generate sufficient heat to kill the disease spores.


Just as with comfrey, every gardener should have a small patch of nettles. If left to grow in a position out of sight, nettles make excellent hosts for beneficial insects as well as activators in the compost heap because they are high in nitrogen and other minerals. Spent Hops

Apart from the beer, this is one excellent reason for living close to a brewery. Spent hops add bulk and valuable nutrients to the compost heap, and I am sure most brewers would be only too pleased if organic gardeners offered to remove the hops for them.

Cow and Horse Manure

Both fresh cow and horse manure are high in nitrogen and hence make excellent activators, and they also add bulk to the heap. They are particularly good if bulky material is in short supply. Both of them also make an excellent soil conditioner quickly if left to rot in their own heap.

Pet Manure

Small animal manures from rabbits, hamsters, gerbils, guinea pigs, and the like are fine to add to the heap. While cat and dog manures do add valuable nutrients to a compost heap, they also contain other organisms that can be harmful to humans and especially children, as well as possessing the obvious disadvantage of the smell. They are best kept off the compost heap.


Urine is an excellent activator for the compost heap because it is very high in nitrogen and potassium. If you are fortunate to have young children that are potty training, you will be able to maintain a good high temperature for your compost heap.


Compost only annual weeds that are not in flower and perennial weeds that have been lifted and left on the top of the ground to wilt and dry completely before being added to the compost heap. If annuals are coming up to flower, cut off the flower buds and add the rest of the plant. Do not add pernicious weeds to the compost heap.

Sheep Manure

Sheep manure is also an excellent activator, being high in nitrogen and most nutrients. When Is It Ready? When ready, the compost should almost look like soil and smell like nectar to any organic gardener. It can then be added to the vegetable plot, fruit orchard, or herb garden.

Poultry Manure

Poultry manure contains much higher rates of nitrogen than other manures and will make a fiery compost.

Pig Manure and Seaweed

Pig manure and seaweed can both be added to the compost heap, having the same qualities.

What Not to Use on the Compost Heap

There are several items that should not be added to a compost heap. Some of these things are not used because they are harmful, while others simply have no beneficial effect. Cooked Vegetables Cooked vegetables tend to putrefy in a compost heap and will only act to attract rats.

Meat and Fish

Cooked or raw, meat and fish will have the same detrimental effect as cooked vegetables on your compost heap.


Soil does not add anything to the compost heap and is much better suited to growing crops.

Glass, Plastic, Metal, and Stone

Obviously, none of these materials will break down and so are useless in the compost heap.

Dog and Cat Manure

As already mentioned when talking about pet manure, dog and cat manure are not suitable for a compost heap. Meat, raw or cooked, will be detrimental to your compost.


The one thing we do not want to do is to spread these weeds around the garden when we use the compost, so unless they are completely desiccated first, pernicious weeds are out. The same goes for weeds in flower or seeding.

Wood Products

Wood products are slow to break down, so compost them in a separate heap and use for mulching.

How to Compost

There are several methods that you can employ to compost materials.

Compost Bin

The best type of compost bin is an enclosed one that will trap all the heat created by the rotting process within the heap and keep the bacteria working to their maximum over most of that material. An enclosed bin with a lid will produce compost the fastest. If a slatted side or open-sided bin is used, the contact with the air will naturally lower the temperature of the outer edge, causing the bacteria in that area to work at a slower rate. To combat this, line the inside of the compost bin with cardboard to act as an insulator as well as ultimately break down into the compost itself.

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Reprinted with Permission from Organic Gardening Techniques and Published by Companion House Books.

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