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Online Compost Class

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Welcome to the City of Davis Online Composting Class!

This online class is intended to give you a general overview of several methods of composting yard trimmings and food scraps. Please read through all the composting information carefully, and then answer the questions below each section. When you are finished with the quiz, click the submit button. You will not be able to save your answers and come back to it later, so please make sure you set aside enough time to complete the quiz (approximately 25 minutes). After you submit the quiz, your answers will be sent to the Public Works Department for review. You will receive an email copy of your quiz as well. Please allow our staff 3-4 business days to receive your quiz, review your answers and respond back to you.

All Davis residents in single-family homes that complete the quiz with 70% accuracy or better (at least 20 of the 28 questions answered correctly) will qualify to purchase a GeoBin backyard composting bin from the City for $10.

Please correct the field(s) marked in red below:

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Backyard Composting

Composting is a natural process that involves microorganisms, bacteria and fungi that break down organic material into humus, or compost. In composting, we work with a variety of factors in order to speed up and control the rate at which organic materials decompose. There are many ways to compost, including backyard composting, worm composting, in-ground composting, homemade food digesters and grasscycling.

When considering backyard composting, most people consider what kind of a bin they will need. A composting bin is not required—all you need to compost effectively is a loose pile in your yard. If you want a compost bin, consider what size you would prefer, based on the amount of space you have available and the amount of material you want to place in the bin.

Backyard composting bins can be constructed from any combination of wood, wire, plastic, or concrete. Choose a design and materials to suit your needs, taste, and pocketbook. You can nail a few wooden pallets together to make a compost bin. Better yet, you can make two or three open-sided wooden pallet bins, so that you can easily turn the compost from one bin to another.

Another kind of a bin can be made with about 10 feet of chicken wire or hardware cloth and a few stakes. Fasten the ends of the chicken wire together to make a hoop and attach the sides to the stakes driven into the ground to give it some stability.

If you do not want to build your own bin, a wide variety of commercial compost bins are also available at local hardware and garden stores. All Davis residents in single-family homes that complete this online class and answer the questions with 70% accuracy or better (at least 20 of the 28 questions answered correctly) will qualify to purchase a GeoBin backyard composting bin from the City for $10. 

Another important consideration in choosing a compost bin is how you will maintain it. Compost needs to be turned regularly, so you will need to be able to access your bin and turn the materials with a pitchfork or shovel. A bin that has an open front (such as the wooden pallet bins shown in the picture above) allows you to turn to your materials much easier turn than an enclosed plastic bin.

Once you select your compost bin, you'll need to find a good place for it. Compost bins can be placed in either the sun or the shade. The most important placement considerations are convenient access to the bin and proper drainage, so that the moisture can drain out of the bin and will not pool up underneath, causing a smelly anaerobic condition.  Make sure your compost bin is placed on top of soil (do not place compost bins on top of impervious pavement or wooden decking) and is not touching a fence, house or any other wood structure. Direct contact with the soil also allows microorganisms, fungi and insects involved in composting to easily access your compost bin and seed the composting process.

1

What method of composting are you most interested in?

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What method of composting are you most interested in?
2
True or false: Compost bins can be made out of a wide variety of materials.
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True or false: Compost bins can be made out of a wide variety of materials.
3
Which would be a good location for a backyard compost bin?
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Which would be a good location for a backyard compost bin?

 

There are four essential factors for maintaining a healthy microbial population in your compost bin: aeration, temperature, moisture content and carbon-nitrogen balance.

Aeration

The contents of a compost bin should be turned once a week so that it remains aerobic (oxygenated). If you do not turn your bin contents regularly it will become anaerobic (lacking oxygen) and will begin to emit foul-smelling odors as well as slow down decomposition. For fast results and for a healthy aerobic compost bin, remember to turn the contents of the bin once a week. Chop materials into small pieces to enhance airflow and increase surface area.

4
How often should you turn your compost pile?
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How often should you turn your compost pile?

Temperature

An active compost bin produces heat as the organisms involved in the decomposition process are metabolizing organic materials in your bin. The higher the temperature of the bin, the more rapid the decomposition rates. A proper “hot” bin can reach 120-180 degrees Fahrenheit. A bin that is smaller than 1 yard in any dimension will have insufficient internal volume to maintain high temperatures.

5
Why does a compost pile produce heat?
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Why does a compost pile produce heat?

Moisture Content

Like other living organisms, the ones in your compost bin require water in order to survive. Compost bins should be kept moist, but not soggy. If the bin is too wet, water will fill up the air spaces and the bin will become anaerobic.40% moisture content—like a damp sponge—is ideal. If your bin is usually uncovered, you should cover it with some type of lid or tarp during heavy rains to prevent over-saturation.

Add water to your bin if it starts to dry out. To test your bin contents and make sure there is enough water, grab a handful of material from the center of your bin and squeeze it tightly in your fist. If your bin has the right amount of moisture, the material will clump together and there will be a few drops of water in your hand. If the material is too dry and will not clump together, you need to add more water. If the material is too soggy and drips water when squeezed, stop adding water for a while (cover it with a tarp if it's raining), turn the bin more frequently and add more dry material to the bin to soak up excess moisture (dried grass or straw).

6
Which statement is the most accurate about moisture in compost piles?
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Which statement is the most accurate about moisture in compost piles?

Carbon-Nitrogen Balance

In order to thrive, the organisms in your compost bin require a "balanced diet" of materials.  Wet or “green” materials, such as fresh grass clippings and food wastes, tend to be high in nitrogen and rich in moisture, while dry or “brown” materials, such as leaves and dried yard waste, are higher in carbon and provide structure to the materials in the bin. Try to maintain an approximate balance of 50% dry carbon-rich materials and 50% nitrogen-rich materials.

7
While compost bin is more likely to be successful?
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While compost bin is more likely to be successful?

Adding Material to Your Bin

In order to provide the microorganisms in your bin with the most “feed stock”, it is important to provide them with smaller pieces of materials. Just as a pile of ice chips will melt faster than a block of ice, smaller items in your compost bin will decompose faster than larger ones.

Chop or shred materials into pieces 12 inches or smaller before adding them to your bin. This will also make your bin easier to turn. Layer material as you place it in your compost bin.  Start by adding a layer of carbon-rich brown material, then a layer of nitrogen-rich green material, etc. This will ensure a proper balance of carbon and nitrogen throughout the bin and will increase the decomposition rate.

8
If you want your compost bin to make compost more quickly, you can (check all that apply):
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If you want your compost bin to make compost more quickly, you can (check all that apply):

Composting Food Scraps

Incorporating food scraps into your compost bin can give you a compost product that is high in nutrients. However, if not done properly, it can attract a number of pests.  Make sure that food scraps never make up more than 10% of the total volume of your bin.

Certain food scraps are OK to add in your bin, others are not. You can incorporate bread, pasta, rice, fruits, vegetables, coffee grounds, and tea bags into your compost bin. Do not add meats, fish, fats, oils, grease, salad with dressing, bones or dairy products to your compost bin. Place meats, fish, salad with dressing, bones and dairy products in your organics cart instead—that material is sent to a professional facility that can accept those materials for composting.

Always chop up food scraps before adding them. Remember, material that is shredded or chopped up will compost faster than material that is not. An intact orange will sit for months as the tough peel will take a while for microorganisms to penetrate. An orange sliced in half or quarters will decompose much more quickly.

Do not leave food scraps sitting on the top of your bin! Placing food scraps on top of the other material in your bin and closing the lid is not enough to keep rodents out. When adding food scraps to your bin, dig into the center of the bin, add some food scraps, then cover it up with trimmings. This will prevent pests (rodents and insects) from infesting your compost bin.

Infestation by either rodents or insects is usually an indication that there is an excess of food scraps in the bin. If you notice signs of pests, stop adding food scraps immediately. After the infestation has ended, you can begin to add trimmings to the bin, but in reduced amounts. If you find you usually have more kitchen scraps than is healthy for your compost bin, consider other composting options.  Remember: most compost bins are not rodent-proof—rodents can easily chew through plastic and wood. Instead of trying to find a rodent-proof bin, make your compost bin unattractive to rodents—turn the contents of the bin once a week, keep it moist and hide the food scraps inside the bin.

9

Which items can be added to your compost pile? (check all that apply)

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Which items can be added to your compost pile? (check all that apply)
10

Which of the statements below is true?

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Which of the statements below is true?
11
If you do not want pests around your compost bin, what should you do? (check all that apply)
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If you do not want pests around your compost bin, what should you do? (check all that apply)

Harvesting and Using Compost

Your compost bin will start producing compost after 3 months. The material in your bin will slowly undergo a transformation. Instead of looking like the materials you incorporated into your compost bin, the contents of your bin will take on a soil- or humus-like appearance. When you turn your bin, you can remove the finished compost and use a seed-planting tray to screen out the unfinished bits(toss them back into the bin for additional composting). Spread the finished compost out and leave it exposed to the air and sunlight to cure and dry.

Finished compost can be turned into the soil as a soil amendment. As much as six inches of compost can be added to your soil each year. When used as a soil amendment, compost reacts with soil to slowly release plant nutrients and essential trace elements. Compost can be incorporated into seed furrows, added to transplant holes for annual and perennial plants, and/or  be used to repair or replace turf areas.

Compost is not a typical mulch, yet it can be applied in the same ways that mulches are used. Compost is a stable product that will not deprive your soil of nitrogen. Spread compost two to six inches thick around plants, trees, shrubs, and exposed slopes. This will deter weeds, prevent crusting, curtail erosion, attract earthworms, and conserve water.

Finished compost can also be combined with equal parts of sand and soil to create an excellent potting mix.

12

How long will it take your bin to create compost?

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How long will it take your bin to create compost?
13

After harvesting the compost from your bin, what do you need to do before using it?

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After harvesting the compost from your bin, what do you need to do before using it?