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QUESTION: How often do you water compost? Blake C

ANSWER: Maintaining the moisture level of your compost at the right point is vital for keeping your compost healthy, as the appropriate amount of moisture supports health and performance of the microbes that help with decomposition and helps control the temperature of your compost.

Too much water in the compost can choke out the available oxygen, leading to anaerobic conditions and slowing down the microbes that break down your compost materials until they’re working at a creep. Too little water can lead to slow decomposition, uneven temperature, and even spontaneous combustion.

Unfortunately, there isn’t a rule that’s set in stone to tell you how frequently your compost will need to be watered because there are so many variables at play. The size of your compost bin will affect how frequently water needs to be added, as will your climate, the materials you are composting, and many other factors. 

What you need to know is this: Your compost should have the moisture level of a sponge that has been wrung out. If it’s drier than a wrung-out sponge, add some water. If it’s more moist than a wrung-out sponge, you’ll need to take steps to balance out the extra moisture. In other words, your compost should be made up of 40 to 60 percent water. 

(If the wrung-out sponge guideline doesn’t click for you, there’s another way to test your compost’s moisture level. Take a handful of dried leaves from your compost—this test only works with dried leaves—and squeeze them in your fist. The moisture level is right when only one or two drops trickle out of the dried leaves when you squeeze them.) Take a few moments to check the moisture level of your compost whenever you’re turning and mixing the compost pile (every few weeks, that is). 

If your compost is too dry, just use your garden hose to sprinkle water into the compost for a few minutes. Alternatively, for a more hands-off approach, if you water your compost the same day as you water your lawn, you can set up your yard sprinklers so that some of the water sprays into your compost bin. You can also counteract dryness by mixing in more wet nitrogen-rich “green” ingredients, such as coffee grounds, freshly trimmed grass, or scraps of fruit and vegetables.

If your compost gets too much hydration and you need to dry it out some, the first thing you should do is prop open the lid of the container, as long as it’s a warm, sunny day. Make sure that if a rain shower begins while your compost is drying out, you close the lid of the bin, or you’ll defeat the purpose and get the compost even more wet. If a day or two of sun doesn’t dry things out well enough, you have the option of removing the compost from the bin and spreading it out in a thin layer to dry off, then replacing it in its container.

Another way to counteract an overly wet compost pile is to balance the wetness out with dry ingredients. Mix in plenty of dry, carbon-rich “brown” materials such as dried leaves, dried grass clippings, shredded newspaper, or shredded cardboard.

QUESTION: How do you jump start a compost pile? Mine seems to not be doing much. -Lewis C

ANSWER: A new compost pile can be a tricky balancing art. Here are a few tips to help you jump-start your outdoor compost pile so that it starts off strong. First, make sure to get the right balance of brown and green materials mixed in your compost pile.

A balanced pile will have an equal ratio of brown to green materials. Brown materials include dead leaves, straw, small twigs and tree branches. Green materials include vegetable and fruit waste, coffee grounds, and plant clippings. 

Another way to jump start your compost pile is to stir and turn your compost weekly. Stirring your pile regularly will help to incorporate oxygen into your pile, and keep temperatures heating up inside your compost, which speeds up the process of decomposition. 

You can also give your pile a speed boost by cutting up large vegetable and fruit rinds and peels into the smallest possible pieces so that they won’t take forever to decompose. Protect your compost from invaders by keeping meat, dairy, oil, grease, and other smelly foods out of your compost heap so as not to attract rodents and other pests to your bin.

QUESTION: How do I know when my compost is ready? It looks sort of like it is, but I’m not sure. – Alex T

ANSWER: You can tell when your compost has finished working by checking its temperature or simply inspecting the compost. It isn’t possible to reliably estimate when compost will be finished because the timeline can vary depending on your balance of ingredients, the size of your materials, the frequency at which you turned the compost, how often you added items to the compost bin, and other factors. The process of transforming from raw materials to mature compost can take anywhere from one month to a year.

When compost has finished its process of decomposition, it will resemble soft, crumbly soil, and you will not be able to identify the ingredients that went into making it. (However, there may be a twig or other item that was tough for the microbes to break down here or there, so consider the overall product.) When compost has finished its process of decay, it will be dark in color: between a very dark brown and black.

Give your compost a sniff, too—when it’s finished and ready to use, it will smell like very fertile and rich soil. This is a pleasant smell, so if you’re catching an aroma similar to ammonia or a rotten or musty smell, your compost has not finished decomposing (and it also needs some tweaking as far as the balance of materials, the moisture level needs adjusting, or it simply needs to be aerated by being turned). And when it’s finished, your compost pile will have decreased in size by about half due to decomposition. 

If you’ve been monitoring the temperature of your compost, you’ll notice it drops significantly when the compost is ready to use. That’s because there’s no more work for the microbes to do breaking things down, and their efforts are what generates the heat in your compost.

Even if you haven’t been tracking the temperature of your compost pile, you’ll notice when it’s complete that the compost is not warm to the touch. It may even be cool enough for some of your backyard earthworms to have moved in. When the compost pile is active, the temperature is too high for earthworms to be comfortable, especially near the center of the pile.

It’s important that you wait for compost to be complete and ready to use before putting it to work in your garden for several reasons. One, before the compost is complete, it’s possible that it could harbor plant diseases or parasites that could be passed along to your garden plants.

Half-finished compost can even burn your plants, not in the way that too strong a dose of fertilizer can do, but with the heat the compost generates when it’s working.

If you still aren’t certain whether your compost is ready to use, it may help to review the compost maturity tests available at the University of Florida Extension’s website [http://sfyl.ifas.ufl.edu/sarasota/natural-resources/waste-reduction/composting/what-is-composting/when-is-compost-ready/compost-maturity-test/]

QUESTION: How do I get rid of flies in my compost pile? My wife doesn’t want to use it at all because she doesn’t like bugs. Robert P

ANSWER: Insects hovering around your compost pile aren’t a cause for concern—in fact, flies and other bugs will actually help the microbes in your compost break down the ingredients. However, you shouldn’t see flies around your compost if you’re maintaining a two-to-one ratio of “brown” carbon-rich and “green” nitrogen-rich materials, making sure to always finish by adding a layer of dry “brown” ingredients to cover any food scraps. You’ll normally see flies buzzing around your compost pile if you’ve been adding lots of fruit to the materials recently. 

You can continue adding fruit without attracting lots of insects by tucking the fruit (and any foods that you add to the compost) underneath the top layer so it’s not sitting right on the surface of the pile. Burying food scraps in the compost heap a bit will prevent flies from being attracted to the area as well as making sure you don’t entice larger pests, like rodents and other animals, to start visiting your compost bin.

If burying your “green” ingredients doesn’t deter insects from your compost, you can continue adding more and more “brown” carbon-rich ingredients, abstaining from adding any more “green” nitrogen-heavy materials, to cut off the insects’ food source until they disappear.

Some gardeners report that they control flies near their compost by turning and stirring the compost on a regular basis to aerate it. Ideally, you should be turning your compost every few weeks to keep oxygen available for the microbes and make sure the compost is completed as efficiently as possible. When you’re trying to discourage flies, you might turn your compost daily or every few days for a while until the infestation abates.

If that trick doesn’t work, you can get a little more aggressive and kill any flies in the compost heap by splashing boiling water onto the compost itself. (Do this when it’s time to add water to your compost anyway to prevent the anti-fly treatment from getting your moisture level out of balance.) The heat from the boiling water will kill both adult flies and their larvae, if any are present. 

Finally, there are lots of reasons to use a lid with your compost, and deflecting insects and other pests is definitely one of them. (A lid also allows you to manage the moisture level and temperature of your compost, ensures the finished product will be ready quicker, contains any unpleasant odors, lets you keep making compost all year round, and protects the completed compost when it’s finished decomposing to prevent it from losing potency.) If you have a lid on your compost bin, keep it closed to keep insects at bay. If you don’t have a lid, consider adding one for the benefit of fending off pests and all the other advantages as well.

QUESTION: Where should compost be—in sun or shade?

ANSWER: If you live somewhere warm, the sun can evaporate the moisture you work hard to get into your compost heap, so a shady spot is a better bet than a sunny one. Although it may instinctively seem like a sunny location will help heat up your compost pile, the sun isn’t a big factor since the heat comes from microbial activity.

In warm regions, choose a shady location so the moisture stays in your compost and it’s more comfortable for you to work with in the summer. That said, avoid choosing a spot too close to a tree, or the tree’s roots may infiltrate through the bottom of the compost as they seek out nutrients.

If your climate is colder and wetter, the rain will likely make your compost wetter than it needs to be, so you should choose a sunny spot to help dry things out.

Learn more about compost bin or pile placement.