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Food Waste Prevention: Composting

13-galCedarGrove_FBFood waste is a significant problem. Americans throw away approximately $165 billion worth of food each year, according to a recent study by the Natural Resources Defense Council (NRDC). The good news is that we can implement changes that can make a big difference.

During the month of September, the At Your Service blog will feature tips to prevent food waste. For our last installment of this series we will talk about curbside and backyard composting. So, you’ve thoughtfully purchased food, properly stored it, and found delicious ways to use it, but what if you still end up with a couple items you need to toss? Compost them!

Kitchen to Curbside Composting

A common concern about composting in the kitchen is cleanliness. Here are some tips to make composting your food scraps easy, clean, and odor free.

  • Use a reusable container with a tight fitting lid for your food scraps. It can be plastic, metal or ceramic. Large yogurt or margarine tubs, juice pitchers, or stainless steel canisters make containing food scraps easy.
  • Put food scraps in a container or wrap them in paper, then put them in your refrigerator or freezer until collection day. Residents say this method works great!
  • Remember to use an uncoated (no shine) paper bag or approved compostable bag to contain and carry food scraps to your food and yard waste cart. Approved compostable bags are made of plant material, not plastic, and have been tested by the compost facility for timely break-down.
  • Keep a routine! Food and yard waste is collected weekly. To avoid smells, take your food scraps out to your curbside cart every few days (even if it’s not full), and clean your kitchen container regularly.

What’s accepted in the yard/food waste cart? Some common items you can put in your green curbside cart are

  • All food scraps, including: fruits, vegetables, coffee grounds and filters, tea bags, shells and bones, pasta and rice, eggshells, nutshells, bread and grains, meat, fish and dairy.
  • Food-soiled (uncoated) paper, including: uncoated (no shine) paper bags, paper towels and napkins, greasy pizza boxes, uncoated (no shine) food-soiled paper plates, and shredded paper.
  • Plant and yard waste, including: flowers & houseplants, leaves, branches and grass clippings.
  • Approved compostable bags. Remember, no plastic bags in the compost.

Some common items that are not accepted in the food & yard cart are

  • No plastic (including plastic bags), glass or metal items.
  • No paper cups, ice cream cartons, or milk cartons.
  • No animal waste of any kind, including diapers, dog poop, cat litter, manure, etc.

For a longer list of items that are accepted or not accepted, click here. SPU also has “Where Does it Go” flyers available in 15 languages and a “Where Does it Go” look up tool to help you sort your waste. For those who are more inclined to watch a video, we have that too! Thanks to the Seattle Channel, you can watch the video at the end of this blog post to learn more what goes in your food and yard waste cart.

compost-foodscrapsBack Yard Composting

Kitchen to curbside composting may be most familiar to residents, but did you know you can recycle kitchen scraps into a fertile, sweet-smelling soil builder? Creating your own backyard compost can help maintain the health of your garden and lawn.

First let’s talk about what you can compost in your backyard, then we we’ll show you two easy methods for backyard composting.

Items you can compost:

  • Vegetables and fruits, bread, grains, spoiled food, coffee filters and tea bags, eggshells, fruit from yard, and food soiled paper or cardboard.

Don’t Compost:

  • Meat, fish, and dairy because these items can attract rats. Put meat, fish, and dairy in your food & yard waste cart. Due to sanitation concerns, pet waste goes in your trash.

How to Compost

Two simple and reliable ways to compost food scraps without pests are burying food scraps in the garden and using food “digesters.”

Burying Food Scraps in the Garden

Burying food wastes at least 8 inches deep in the garden is a safe and easy way to compost. Garden soil provides a natural barrier that keeps out flies and other pests, and holds in moisture and odors. Bonus, you don’t need any special tools.

Step 1: Select a spot. Food scraps can be buried in empty areas of vegetable and flower gardens, or in holes outside the drip line (below the ends of branches) of trees and shrubs.

Step 2: Dig a hole. Use a shovel or post hole digger to dig a hole or trench about 1 foot deep.

Step 3: Add food scraps. Add 2 to 3 inches of food scraps to the hole. Chop and mix scraps into soil.

Step 4: Cover with soil. Cover food scraps with at least 8 inches of soil to keep pests out.

Step 5: Watch for pests. Check for signs of digging by rodents, dogs or other pests. If you see signs of digging, it may be better to switch to a digester or worm bin that excludes pests.

Step 6: Plant. Food scraps may take from 1 to 6 months to decompose depending on the season, moisture, soil and what is buried. Seeds and small seedlings may be planted on top of buried food scraps immediately. Large transplants should not be planted until food has decomposed.

Food Digesters

Food digesters are partially buried metal garbage cans or other containers with tight- fitting lids, and holes or mesh screens in the bottom providing access to the soil. Digesters provide more protection from pests than garden burial, and require less work than digging holes for burial or maintaining a worm bin. Follow these steps to start a digester:

Step 1: Get a digester (or two). Digesters can be purchased through many garden supply catalogs. Call the Garden Hotline at (206) 633-0224 for more information. Using two digesters makes management easy. One digester can be fed for active composting, while compost in the second finishes decomposing before harvest.

Step 2: Select a spot. Find a convenient spot in the garden that has at least 18” of well-drained soil. If your soil drains poorly, consider building a mound of soil to set the digester in.

Step 3: Dig a hole (or two), and install digesters. Use a shovel to dig a hole large enough to bury the base of the digester 17 inches deep, or according to the manufacturer’s instructions.

Step 4: Add food scraps and cover material. Add layers of food scraps as they are generated. Though this is not essential, we recommend covering each addition of food with a thin layer of shredded paper, sawdust, peat or coco-coir helps to speed composting and reduce flies.

Step 5: Harvest. Digesters can be fed for 6 to 12 months before they are full of food scraps.

If you have two digesters, when the first is full, stop using it, and use your second digester for the next 6 to 12 months. When the second digester is full, shovel the finished compost out of the first unit for use in the garden, and begin using that unit again.

If you only have one digester, shovel the compost and decomposing food scraps out of the digester when it gets full, and bury in the garden.

Using Compost

Now that you’ve made some high quality compost, here are some ways you can use it to improve the health of your garden or lawn.

  • Use Compost as a “mulch.”
    • Spread a 1-2 inch layer around plants and trees, to fertilize the soil and help hold moisture.
  • Dig Compost into soil when planting.
    • Mix 2-4 inches of compost into the upper 8 inches of soil for vegetable gardens, or when replanting landscape beds.
  • Spread a thin layer on lawns.
    • Rake 1/4 inch of compost into lawns, in the spring or fall.

For more information, check out this guide to composting at home and this composting FAQ. Do you have more interest in yard waste composting? We have a blog post about it here. Remember, you can always call the friendly folks at the Garden Hotline at (206) 633-0224 or send an email to if you have any questions.

That’s a wrap on our food waste prevention series! We hope you enjoyed it, learned something new, and are inspired to find ways to incorporate waste prevention methods in your life. Do you have any ideas or thoughts for another SPU blog series? Let us know by leaving a comment on this blog post, tweet us, or post on our Facebook.