Stop Food Waste Week

Composting FAQs

Where should I put my composting system?

Almost all composting systems should be shaded from the sun to prevent them from drying out. Ground-based compost piles and bins should ideally be placed on bare soil to allow beneficial organisms to gain access to your bin. But, with the right mix of greens and browns, they will work anywhere, albeit a little more slowly if not on soil. A wormery should be placed in the shade and can be kept in a shed to protect it from extreme weather conditions, and a Bokashi system can be kept in the kitchen. A Green Cone, unlike most other systems, needs to be in a warm sunny spot.


Can weeds be composted?

In slow, cold composting conditions, weed seeds and tough plant parts will survive.

To avoid releasing these in your garden, it is best to pick weeds before they go to seed, and to avoid adding roots or stems from docks, briars, bindweed, ivy or other noxious, perennial weeds.

In a hot composting pile, seeds and chopped-up vegetation will be killed by the high temperatures in the middle of the pile, but maintenance of high temperatures requires some management and manual turning of the composting material.

If you have lots of weeds, it’s best to create a dedicated pile in a sunny spot and cover with black plastic. This should dry and heat the weeds enough to kill them.


Is there anything I can do to speed up the composting process?

Follow all of the essentials of composting that can be found in the compost booklet, including chopping things up into smaller pieces, properly balancing of “green” and “brown” materials, turning the pile to add air or fluffing it up to encourage passive aeration, and making sure that materials are moist but not waterlogged to promote optimal composting.


Should I cover my composter?

In rainy Ireland, covering your composter is a great idea. During the winter, a cover stops the materials becoming waterlogged. In summer months, covering the pile keeps moisture in. While many composters come with lids, open piles should be covered with plastic, old carpet, plywood or anything else that works for you.


There are loads of flies in my compost system – what can I do?

Flies are attracted to rotting food on top of your compost. To avoid this, mix and bury your food waste within the existing material in your composting system, or add a layer of brown materials such as leaves, shredded paper, or sawdust on top of each layer of food waste.

If the problem persists, leave the lid off for 2-3 hours on a sunny day and then place a layer of wet newspaper on top of the composting materials to create a physical barrier and replace the lid.


Can ashes from the fire, stove or BBQ be composted?

Ashes should not be added to compost systems because they fill in air spaces and can suffocate your compost. More importantly, they are alkaline in nature and would upset the near neutral pH balance of the compost. However, they do contain potassium, a valuable plant nutrient, and can be directly added to acidic soils at planting time to help increase fertility. Wood and peat ash are safest. Coal ashes may contain heavy metals and other toxins so they should not be used for gardening.


What about pet waste?

Wastes from plant eating pets, such as horses, rabbits, gerbils, hamsters, guinea pigs or birds, can be safely composted at home. Just remember that all pet manures are “green” materials, high in nitrogen so they need to be balanced with “brown” materials. Waste from meat eating pets such as cats or dogs should not be composted for use in the garden because of the potential to spread disease.


My compost smells, what can I do?

There are a few of reasons why your compost may smell, including:

  • The compost is too wet due to being exposed to rain.
  • It contains too high a proportion of “green” materials such as grass clippings and food scraps.
  • It contains food scraps containing animal products such as meat, fish, skins or dairy products.

In the case of the first two the solution is similar – turn the compost and add some drier “brown” materials and mix thoroughly. If the compost is getting wet due to rain then make sure to cover it.

If you are putting meat or other materials of animal origin into the food scraps to be composted, these could be causing the smell. Collect only vegetative kitchen scraps for composting and consider using a Green Cone system or brown bin collection service for non-vegatative foods.


Does my compost need to be turned?

No, not necessarily. Many bins work by simply adding materials to the top while harvesting materials out of the bottom. Turning allows you to add air and, if necessary, moisture to speed up composting. If the opening of the compost bin is too narrow to turn the pile, simply lift the bin up off the compost, place it next to the compost materials and turn them back into the bin. For larger piles, placing a perforated pipe on the ground when starting off can promote both passive aeration and drainage if necessary.

Finally, you can purchase a spiral compost mixer that acts like a giant corkscrew to mix things up in a narrow, stationary bin.


There are lots of worms around the lid of the compost unit – is there something wrong?

Worms naturally make their way to the lid of the compost bin so don’t worry – they will make their own way back down when they want to. The fact that there are worms in your bin is a very good sign.


Are rodents a problem when composting?

Simple answer- yes they can be, but not if you manage your composting system properly.

There are two reasons why rats are attracted to compost. The first is food. Vegetative food scraps that are easily accessible (i.e. have not been buried within the composting material) or high protein scraps such as meat, fish, bones or cheese will attract rodents looking for something to eat. The second is that compost piles can be a warm and dry home for nesting, especially in winter months. If you find that rats are nesting in your bin, you can simply turn the pile to disrupt nesting behaviour.

To discourage rats from getting in your compost system, bury all vegetative food scraps within composting garden materials, avoid composting foods of animal origin and place the bin on a surface they can’t burrow under like hard plastic or thick wire mesh.


How long does it take to make finished compost?

This depends on the system you are using, the type of materials you are trying to compost, and whether or not you are following all of the essentials of composting. In general, holding systems take longer than turning systems. You can expect that any materials you add to a holding system in one gardening season would be ready the following year. For turning systems, compost can be ready in as little as 8 weeks. For wormeries, compost can be harvested in 6-12 months for a box (harvest entire contents at once) or in 1-2 months for a stackable wormery (harvest small amounts at a time). Proper use of Bokashi should speed up the decomposition of food scraps in your composting or burial system too.


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