Compost is a mixture of rich, dark, crumbly organic material that is a wonderful soil amendment and natural fertilizer for your garden.
Composting is the process by which vegetable matter, manures, and other organic materials are broken down by worms, insects, and microorganisms.
Adding compost builds soil structure, promotes aeration and drainage, encourages microbial activity, and provides vital micronutrients that are released slowly over time in a form easily absorbed by plants.
Compost is also a great way to recycle kitchen and yard waste. Composting can divert as much as 30% of household waste away from the garbage can, which also helps reduce landfill waste.
Here are some tips to help you build healthy soil for your kitchen garden or small farm.
Getting Started: Compost Tools
All the tools you really need to start composting are a spade or shovel, a long-handled fork, and something with which to chop up larger stems and prunings. But like most jobs in the garden, having the right tools for the task makes it a whole lot easier. Here’s a list of the five best tools for basic compost tasks, all of which we carry at our Healdsburg store.
- Pointed-blade shovel: The most versatile choice if you buy only one digging implement. It performs the same chores as a rounded-blade shovel, while also allowing for easier digging in compacted clay soils. The pointed blade is useful for chopping up organic matter into smaller pieces before tossing it into the compost pile.
- Compost fork: Use to turn the compost and keep it aerated. A compost fork can sometimes be like a pitchfork, but there are also ones available that are sort of a cross between a pitchfork and a shovel to aid in picking up and turning your compost.
- Compost aerator: Especially useful if your compost is contained in a bin, which can be harder to access with a fork. The aerator allows you to drill down onto a heap and bring material from deep within up to the surface with ease and efficiency, while sparing your back from unnecessary strain.
- Compost thermometer: Can be used to troubleshoot some of the most common composting problems. For instance, if you recently built your pile and it’s not heating up, you may need to add more water, manipulate the aeration, or re-balance your ingredients.
- Compost sifter: Allows you to separate the coarse, unfinished compost ingredients from the finished compost. A sifter also creates an easy means of separating out the trash, stones, and debris from your pile before using your compost in your garden.
How to Start Your Compost
- Start your compost on bare earth to allow worms and other beneficial organisms to aerate the compost and access your garden beds.
- Lay small branches, woody stems, and twigs a few inches deep to encourage drainage and help aerate the pile. A healthy compost pile is usually at least 3-5 feet square; this size helps retain moisture and heat generated by bacteria so that materials decompose quickly.
- Add compost materials in layers, alternating between a combination of brown and green plant matter. Shredded newspaper, dry leaves, and straw are ideal for the brown elements; kitchen waste and grass clippings are perfect for the green add-ins. A healthy compost pile should have more carbon than nitrogen, a simple rule of thumb is to use 2 parts carbon-rich (brown) matter to 1 part nitrogen-rich (green) matter.
- Keep compost moist. Moisture in compost is critical and having too much or too little can slow or sour the process. The moisture content of your pile should be kept at around 40-50%, enough to feel like a wrung-out sponge.
- Turn the pile with a pitchfork or aerator every few weeks to blend all of the materials. This will help to infuse your pile with oxygen, which is essential for the aerobic bacteria that decompose the materials.
When is the Compost Ready?
It can take anywhere from a few weeks to about a year for your compost to be ready to use. The time it takes depends on the size of the pile, the materials you used, how often you turned the pile, and the ratio of greens to browns.
In general, compost is ready when it’s dark and crumbly and mostly broken down with a pleasant, earthy, soil-like smell to it.
Often, there are still bits of matter such as twigs or rocks that are not fully digested in the compost. While it’s not always necessary to sift your compost before spreading it in the garden, it makes for a better planting medium without all those lumps and clumps, and also ensures that only finished compost goes into the soil. Sifting also aerates the compost, improving the soil structure of your garden beds.
Where to Use Compost
- New planting areas: Give new planting areas a boost by digging in as much compost as you can spare (up to four inches) into the top six to twelve inches of garden soil.
- Established planting areas: Established plantings will benefit from an inch or two of compost worked into the top few inches of soil. Be sure to leave a gap between the compost and the base of the plant to avoid burning the stems – the nutrients will find their way down to the plant roots.
- Around trees and shrubs: Compost makes a great mulch. Spread a one to two-inch layer over the soil surface starting from six inches from the trunk out to the edge of the dripline of the tree or shrub.
For more on composting, read our blog Make Your Own Dirt!