Compost is ready to use after anywhere from one to 12 months, depending on the size of the materials placed in the compost system, the degree of management, and the intended use. Compost that will be used as a top dressing or mulch can be applied after the least amount of time.
Test whether the compost is ready...
Decomposition will be complete anywhere from two weeks to two years depending on the materials used, the size of the pile, and how often it is turned.
When it's ready to use, compost has a crumbly texture and a rich, earthy smell. You may still see sticks, roots, and other intact plant parts in otherwise well-rotted compost.
In general, the older the compost, the fewer nutrients it offers. Compost contains nutrients like nitrogen, phosphorus, and potassium, but only small amounts. Also, they are transferred to the soil over a long time. Well-balanced compost also contains many other micro-nutrients that are helpful for plant growth.
If a compost pile is just left sitting, and not turned, it will take 6-12 months or longer to completely break down, depending of the climate and weather. The cooler it is, the longer it will take.
Turning once a week or once every two weeks had generally lower decomposition rates. To maintain a thermophilic pile (pile with high heat), it should be turned every three to four days, or when the temperature drops below 104 F. However, if most of the material has been decomposed, less frequent turning is adequate.
Does composting produce soil? The end product of composting is not soil. Instead, decomposing organic waste produces a nutrient-rich and biologically active substance, which can be added to the soil. But it does not turn into soil.
Compost loses volume over time
The shrinkage does continue but slows down considerably as the compost becomes more stable. However, it will still slowly decrease in bulk over time. If you leave it too long, you are feeding microorganisms in the compost, rather than in the soil.
Furthermore, immature compost in soil continues to decay, a process requiring both nitrogen and oxygen. When these elements are being used to degrade organic material, they're unavailable to plants. For all of these reasons, it's important that compost be thoroughly mature before it is applied to soil.
There are no worms or bugs in the pile.
A healthy compost should have a plethora of worms, mites, and mycelium visible if you were to turn it over with a pitch fork.
A compost pile needs to be kept moist but not waterlogged. A 50% moisture level is the ideal average to aim for. What is this? As compost piles are exposed to the elements, keeping their moisture at the coveted damp, not soggy level can be tricky.
If you keep adding fresh material to a pile or bin, your compost will never be ready to use. Once you mix enough material, don't add any more so what's there can cook. Depending on how hot your pile gets, it usually takes between 3 weeks and 3 months to get finished compost.
Egg shells are an excellent addition to a compost pile, as they provide calcium and other key nutrients. Whole eggs, egg whites, and egg yolks do not belong in the compost pile, though.
Answer: You can add moldy food (vegetables and fruits only) to a backyard composting bin anytime. Mold cells are just one of the many different types of microorganisms that take care of decomposition and are fine in a backyard bin. If you're using a worm bin, you have to be a bit more careful.
Adding nitrogen-rich materials
The microorganisms in compost need both nitrogen and carbon to work. If there is too much carbon, the process will slow down. To speed up the process try adding 'greens' – items that are high in nitrogen, such as grass clippings or manure.
The rule of thumb for an active, hot pile is every three days until it stops heating up. Some over-enthusiastic composters rush out after a day and turn the pile. This is a bit too much of a good thing.
A covering holds heat in the pile, which helps the good bacteria to work more efficiently. The cover effectively speeds up the process, shaving weeks (and even months) off the time required to produce finished compost. Kill pests.
Remember - your compost bin is only a receptacle. Empty out your scraps every few days or every week in your outdoor compost pile OR your green waste bin to be collected on garbage day!
Three factors are usually to blame: poor aeration, too much moisture, or not enough nitrogen-rich material in the pile. A compost pile overburdened with materials that mat down when wet—grass clippings, spoiled hay, heaps of unshredded tree leaves—can become so dense that the pile's center receives no air.
The bacteria that break down leaves, grass clippings and other yard waste into compost need air to function. The air that's available to them can be tiny pockets — almost microscopic — tucked inside a pile of twigs, leaves, banana peels and coffee grounds.
Assess the nutrients in your soil
Soils with excessive compost applications, particularly manure, tend to develop high concentrations of nutrients such as ammonium, calcium, magnesium, potassium and sodium. These soils can also develop high concentrations of bicarbonates, carbonates and hydroxyls.
As the compost begins to cool, turning the pile usually will result in a new temperature peak because of the replenished oxygen supply and the exposure of organic matter not yet thoroughly decomposed. After the thermophilic phase, the compost temperature drops and is not restored by turning or mixing.
Spread 2 to 3-inches of un-sifted compost on the upper surface. Use the garden fork with a twisting motion to mix the compost with the loosened topsoil. Wet down the bed and wait 4 to 7 days before planting to give it time to settle.