Compost piles vary so much in how they are built and used. Some piles are built loosely in the gardens, while other bins are contained and can be moved around. Having your compost piles built into a bin can speed up the composting process and protect your food waste from pests.
Unfortunately, compost bins can either come with a bottom (base plate) or without one. Whether or not your compost bin needs a bottom or not depends on what your climate is, how your yard is set up and where your compost will be located. Let’s find out if a bottom is needed!
Does a Compost Need to Have a Base Plate?
Compost piles with a bottom can produce finished compost from a brown material and garden waste, as well as food scraps and kitchen waste. Bins with bottoms do not have to worry about rodent problems but may have drainage issues. Bins with bottoms retain heat and water better than their bottomless counterparts.
Bins without bottoms drain freely and allow garden waste and food waste to be piled high. Microbes and worms already in the soil the bin is placed on will get to work faster than in a non-inoculated compost pile. Using the layering method and allowing for air flow makes bottomless bins more successful with the aerobic process than tight-bottomed bins.
What Are the Parts of a Compost Bin?
The different parts of a compost bin can be adjusted to turn organic matter into black gold. By adjusting the components of a compost bin, you can have better control over the finished product and more consistency in your composting material. Experienced gardeners can increase the volume of material and nutrient content of their soil by customizing their compost heap.
| Part Name | Use | Materials |
| Lid/Cover | Keep out moisture and pests | Plastic lid, tarp, or burlap |
| Bin/Pile | Hold material together and retain heat and moisture | Plastic, metal, wire mesh, or pile |
| Bottom/Base | Improve drainage and keep out pests | Plastic, metal, mesh, or wood |
Lid/Cover
The lid or cover of a compost bin is very important. If the top of your compost is an open hole, then water and pests can easily get in and mess with your pile. Lids painted black can trap a ton of heat and warm compost bins up even in the winter. The odor and sight of the decomposition process are hidden by lids on bins.
Lids can also lead to a build-up of anaerobic pockets that can breed pests and fungi. Too much liquid can kill off good bacteria and beneficial organisms. Lots of cardboard and crumpled-up paper can be added to increase air pockets in compost piles with lids. Lids that have vents can be helpful in maintaining an optimal moisture level but should be closed when rain is expected.
Bin/Pile
The container that holds the organic materials like twigs and dry leaves can either help or hinder compost making. If the bin allows good airflow, such as one made of wire mesh or with plenty of air holes, then the compost will have a lot of oxygen but may dry out quickly or get cold in the winter.
Other bins are made of solid plastic or metal, with no space for air or pests to enter the compost. These bins hold moisture well and can heat up in the summer sun. Make sure closed bins have dry leaves, cardboard, and paper to balance the coffee grounds and kitchen scraps in the compost. A compost aerator can help increase oxygen in sealed compost bins to keep composting organisms alive.
Bottom/Base
Using a bottom or base plate can help keep your yard clean but can also slow down how long it takes to get finished compost. The method of using a bottom or base to keep your compost contained and safe from burrowing pests is a good idea if you have winters and wild animals. The food scraps need to be protected from rodents, and a bottom seals them in.
Leaves, branches, straw, cardboard, smashed-up paper, and other carbon materials can be used as a base instead of plastic or metal. These materials will keep pests away from food but may attract wild animals that want to burrow during the winter. Wire mesh can be used to create a bottom that still lets air flow and drainage occur freely.
Benefits of Bottoms on Bins
Some compost bins will benefit from having a bottom. When you look at the advantages of bottoms on compost, it is important to consider what will help your garden build soil faster and why?
- Off the Ground – Compost piles sitting directly on the ground will lose heat and moisture faster than one with a bottom. The ground under your compost heap will affect the condition of the pile and will need to be accounted for when choosing a site. Picking sunny spots can help make usable compost faster by keeping the temperatures high.
- Protection from Pests – Most rodents and invasive bugs will enter a compost pile from below. A bottomless compost offers no protection, and pests can work their way inside, ruining a batch of compost. Fruit scraps and other green material will be safe from rodents if you have a bottom on your bin. Leaf mold and yard waste near the base of a bin will keep pests from trying to chew through the bottom.
- Many Different Types – Several different types of bottoms or base plates can help make your compost even more customizable. Mesh wire or burlaps can be placed under bins to discourage pests but allow compost moisture to drain. A compost container that needs to be moved should have a solid bottom like wood, metal, or plastic. Using different bottoms can help your compost get air when it needs it and protection from pests when that’s needed too.
- Reduces Stains – Fresh compost and compost tea can both leave nasty stains on concrete or paved areas of a yard. If the liquid leaks out or the compost stays in one place for a long time, the ground underneath will be stained. Garden compost should be placed on a base to keep unsightly stains from forming. Preventing inches of compost from spilling out the bottom of the bin can keep ants and other pests away and reduce odors.
- Easy to Move – A bin with no bottom will drop compostable material all over your yard and garden if you try to move it. To get excellent compost from one area to another, you will need to use a wheelbarrow or other hauling method. A bin with a bottom can be navigated to a new location with different techniques. With a bottom, you can move your compost and not leave a trail of dark material all over the yard.
- Easier to Harvest – When using a shovel or pitchfork to harvest the compost, hitting the bottom stops you from digging into the yard’s soil. When you try to lift out compacted soil and not compost, it could hurt your back. Having a bottom allows you to dump and scoop easier than an open-bottomed compost bin.
Disadvantages of Bottoms on Bins
Putting the wrong type of bottom on a compost bin can cause issues. Most of these issues can be easily fixed, but understanding what they are is needed first. These issues can ruin an otherwise perfect batch of compost, so watch out.
- Drainage Issues – A bottom without drainage holes can lead to a soggy and anaerobic area. The foul smell will be released when you try to harvest in the pile and can attract pests. These drainage issues can lead to loss of nutrients and maggots and other unsightly compost problems. Poke holes in the bottom or use a different material to reduce drainage issues.
- Airflow Issues – Without slits or areas for air to enter the pile, decomposition can slow down. Air is important, and providing space under the pile for circulation can help the microbes work harder. A thick base can prevent this air circulation and cause problems. Add more brown materials to improve compost structure and turn often to compensate for a solid base.
- Separation from Soil Microbes – A compost with a base cannot recruit decomposers from the soil under it. All critters in the compost must be added through inoculation via other past composting material. Without these microorganisms getting a head start, the whole composting process can take longer. Add lots of old composting material if you have a base between your compost and the ground.
- Hard to Harvest and Flip – The bottom of the bins, whether it is solid or mesh, can catch the shovel or pitchfork and make harvesting harder. Bottomless bins can just be lifted up, and the compost scooped, but a bin with a bottom needs to be maneuvered more carefully. A solid bottom compost is better for harvesting and flipping than burlap or chicken wire bases, as the shovel is stopped and does not get tangled or stuck.