compost in a bin
(Image credit: Grahamphoto23 / Getty Images)

Here at Gardening Know How we get lots of questions, and our goal is to provide answers to those inquiries to the best of our knowledge. Many of these queries involve composting. Whether you're making your own compost or compost tea, or simply buying it, gardeners have lots of questions. Here are 10 of the most commonly asked questions regarding compost.

How do I start a compost pile?

When composting, first choose an open, level area with good drainage in partial sun to shade. Also, consider the size of your compost pile; an ideal size is 3 feet high (just under a meter) and no taller than 5 feet (1.5 m). Start the pile directly on the soil or on a wood pallet if you prefer. Start layering your green and brown organic materials beginning with a layer of bulky browns, like twigs, followed by a green layer such as grass clippings. Keep alternating in 4- to 6-inch layers. Lightly water each layer as it is added. The compost pile should be moist but not sodden. Monitor the moisture level and water as needed, turning the pile every so often.

Why does compost turn into balls instead of nice and crumbly?

Balled up compost commonly occurs when using a tumbler. It isn't anything to worry about. The balls of compost usually break down on their own or you can crumble them yourself. All it means is that there is too much moisture in the tumbler, either because you added water or there's a lot of moist, green material. When composting the next batch, add more brown material, such as dry leaves or cardboard. The same would be true for balled up compost in a pile. Turn the pile more frequently to aerate it and add in more brown material.

Why are there flies in my compost and how do I get rid of them?

The flies in compost are attracted to the organic material in the pile, specifically the food scraps. If the flies are a nuisance, the organic material needs to be buried under brown or carbon material, such as brown leaves or cardboard. If you keep about a foot of brown material atop the food scraps, the flies won't be interested anymore. Chances are good that if you have a fly problem, you also have an odor problem. This means the compost pile isn't heating up enough to break down the organic material rapidly. Adjust the pile so it has a ratio of 4:1, brown (carbon) to greens (nitrogen).

Are coffee grinds good for compost?

Yes, coffee grounds are great in compost. They help add nitrogen into the compost pile. You can add both coffee grounds and filters to the pile; just remember that they are considered green material and need to be balanced with brown compost material. The ratio for brown or carbon material to green or nitrogen material should be about 4:1. Coffee grounds can also be worked directly into the soil, but they will not immediately add nitrogen as they do to compost. They will, however, improve drainage, soil aeration and water retention.

Should you remove the inner lining when composting eggshells?

No, there is no reason to remove the lining from the eggshells. Introducing the entirety of the eggshells in compost adds calcium to the finished compost product, an important nutrient that helps build cell walls in plants. You may, however, want to wash the eggshells before adding them to the compost pile to reduce the potential of disease from raw eggs and also so they don't attract the attention of animals. Another good idea is to break the eggshells into smaller pieces so they degrade more rapidly. This isn't necessary, but whole eggshells will take some time to break down.

Can I safely use wood ashes in compost?

Absolutely! Putting wood ash into the compost pile adds valuable nutrients such as potassium, lime, and other trace elements necessary to healthy plant growth. Also, compost piles may become a bit acidic and wood ash, alkaline in nature, can offset this. One caveat, however, don't use ash from charcoal grills. The charcoal has been treated with chemicals that may not break down in compost. These harmful chemicals may then be passed onto plants. Use wood fireplace or campfire ashes only.

What is the ratio for making manure/compost tea?

Similar to compost tea, manure tea can be used each time you water your plants or every so often. It is, however, extremely important to dilute the tea prior to use so it doesn't burn the plants. Be sure to use only well cured manure and steep 5 parts water to 1 part manure. Allow the manure tea too steep for a week or two. Once the tea has steeped and you are ready to use it, dilute 1 cup of tea with 1 gallon of water (240 ml with 3.8 L).

How do you store compost?

Compost is alive with microbiotic bacteria and other organisms that need food, moisture and aeration to stay alive. In order to store the compost for any length of time, it needs to be supplied with these three requirements. Where you store the compost depends on how much room you have, but the easiest way is to store it in an out of the way area in the yard, covered with plastic to keep it protected. Compost can also be stored in a plastic container or trash bin, just be sure to add a bit of water every few months to keep it moist. Don't add too much water or the compost will mold. Just add enough to keep it slightly damp and all those beneficial organisms happy.

Can compost have E. Coli in it?

There is some concern regarding composting of meat or even some manure that may be infected with E. coli or other potentially dangerous bacteria. That's why these items are generally not recommended for use. Most commercially produced compost should be heated enough to kill off any harmful pathogens. If you are making your own compost, be sure that its internal temperature remains 90-140 F. (32-60 C.). When compost is "cooking" properly, it will not only destroy seeds and weeds, but kill off most harmful bacteria. A hot compost pile will also break down more rapidly.

What is green and brown compost?

Both brown and green materials are needed to "feed" a compost pile. Brown material includes dry leaves, sawdust, straw and newspaper and is brown in color, consisting of dry or woody plant material. Green material is wet or freshly cut or clipped material such as grass clippings, weeds, coffee grounds, manure or food scraps. Brown materials add bulk and help to aerate the compost and are an important source of carbon. Green materials add nitrogen into the pile as well as other nutrients necessary for healthy compost. It's important to have a ratio of about 4:1 brown (carbon) to green (nitrogen). A good ratio of brown to green material will allow the pile to heat up enough to kill seeds, weeds, and harmful bacteria as well as to facilitate the rapid breaking down of the material into compost. We all have questions now and then, whether long-time gardeners or those just starting out. So if you have a gardening question, get a gardening answer. We're always here to help.

Amy Grant

Amy Grant has been gardening for 30 years and writing for 15. A professional chef and caterer, Amy's area of expertise is culinary gardening.