Congratulations! Your compost is ready to use.
It can take anywhere from four weeks to twelve months to produce your finished compost. The time it takes can vary widely depending on the materials and methods used.
The point at which the compost is ready varies depending on how the compost will be used. In general, though, compost is ready when it's dark and crumbly and mostly broken down with a pleasant, earthy, soil-like smell to it.
For most uses it is acceptable to have some recognizable pieces of leaves or straw remaining in your compost. However, you should not use partly finished compost either as a seed starter mix or in areas where heavy nitrogen feeding plants are to be grown. Because unfinished compost is still actively breaking down, organisms in the material continue to take nitrogen from their surroundings. When mixed with the soil, the organisms will begin to draw the nitrogen from the soil in order to have the energy to continue the decomposition process. The result is a nitrogen defecit in the soil to the detriment of the plants in the area. Signs of nitrogen deficiency are stunted plant growth, yellowing leaves often near the bottom of the plant, light green or yellow foliage and weak stems.
Unfinished compost has also been known to damage or "burn" some plants and plant roots. This is a result of the heat given off by the decomposition process. When using unfinished compost it is a good idea to leave a few inches between the material and the stems of plants.
Unfinished compost has also been shown to inhibit the germniation of seeds. If unfinished compost is to be applied to areas where seeds will be sown it should be done six to eight weeks before seeding begins. Ideally, compost should be applied in the fall for an area that will be seeded the following spring.
More: Test whether your compost is ready »
Compost is unparalleled as a soil conditioner for:Wait until your compost is completely finished before you use it for indoor plants. Established house plants will benefit from an inch of compost mixed into the top inch or two of soil.
Container plantings will benefit enormously from the addition of compost to the potting soil. Ensure that you use only mature compost in your containers to avoid burning any tender stems or roots.
Here is a good recipe for a compost based potting mix suitable for containers: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 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.
Spread up to ½" of finished compost over an established lawn. Compost used as a top dressing for lawns should be fully broken down. Running the compost through a fine compost screen is a good idea to keep out any chunky bits. Large areas should be covered with a fertilizer spreader but smaller areas may be spread by hand or with a shovel. Aerating your lawn prior to spreading compost will be of additional benefit, enabling the compost to filter down under the sod more easily.
Starting a new lawn is often challenging, particularly in areas with new homes where the builders have removed the original topsoil. The addition of compost to the existing soil can greatly improve the chance that a new lawn will take hold and thrive. Up to three inches of compost worked into the top six inches of soil will give the new lawn an excellent start. Either sod or grass seed can be placed on top of the amended soil.
Spread a once 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.