Compost Lecture at the NUFS (Nutrition Food Sciences) Lab

Hello everyone, this is Lacey Benson. Amanda Soon and I gave a short presentation last Wednesday for the nutrition food sciences lab about preparing food scraps for composting. We wanted to explain how to prepare food scraps to the nutrition lab students because they take advantage of the compost bin by CCB on campus. We also wanted to tell them that the bin is brand new donated to G.R.O.W. (Growing Roots of Wellness) from Sarah Smith of the Santa Clara County Master Composter Program. The bin is an Earth Machine which usually costs $55 if you buy it subsidized from Santa Clara County. Below I have included some key points from our presentation about composting and preparing food scraps for a compost pile.

What is Compost?

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• The basic ingredients in a compost pile are carbon, nitrogen, oxygen, and water
• Food scraps are generally a nitrogen and water source that decompose quickly (w/in days)

Benefits of Composting

• Composting diverts valuable organic materials from landfills (about 40% municipal solid waste is organic materials -EPA)
• Composting recycles organic materials and replenishes lost soil nutrients that are taken out through plants that is naturally recycled by dropping leaves and debris but is instead collected by humans and turned into a simpler food source for soil organisms and plants.
• Composting reduces methane emissions by diverting organic materials from landfills, where they would anaerobically decompose producing CH4 (methane) a greenhouse gas (GHG) 22-24 times more potent than CO2.
• Composting also creates a closed loop system - it gives nutrients to soils which plants then take up, after which the remains are composted and recycled into a usable form for plants and organisms again and the cycle then continues; creating a closed loop system which ideally replicates natural systems.

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Types of Food Not Acceptable for Composting

• meats
• dairy (cheese, yogurt, milk, butter, tofu, etc.)
• bones
• oils or fats (e.g. olive oil and butter)

Note: the above are not acceptable for composting because they attract rodents and other vectors that carry pathogens; also they smell really bad when they are broken down by microorganisms so avoid adding these into your compost bin/pile whenever possible!

• bread (due to allergies)

Note: bread should not be added because the mold that grows on it produces penicillin spores which if you are allergic and you breath in can cause you to go into shock (not good). So to be on the safe side if you do not know if you are allergic to penicillin then you should not add bread to your pile.

• plastic (even if it says compostable)
• stickers and wire ties as well as rubber bands

Note: no matter what you've heard compostable plastic is a myth when it comes to backyard composting. Compostable plastics are designed for breakdown under large-scale commercial composting conditions.

• corn cobs
• stone fruits (avocado, peaches, apricots, etc.) unless the woody pit is removed first

Note: corn cobs and stone fruit pits are highly resistant to decay because they are woody materials, I do not usually add them to my pile because they take so long to decompose but feel free to there's nothing wrong with adding them they just stick around even after all of the materials in your pile have decomposed.

How to Prepare Food Scraps

• Roughly chop materials so they have more surface area for micro- and macro-organisms to digest the food.
• Make sure no food is whole or in too large or pieces or it may become anaerobic and begin to smell and take longer to decompose.
• Also a very important step to always do is to cover the food scraps when adding them to the pile. Never allow them to stay out in the open, otherwise it will attract unwanted flies and guests. Food scraps are best placed as close to the center of the pile because it is the warmest and where decay is occurring the fastest.

Want to Learn More?

• Attend a free Home Composting Class visit reducewaste.org to see upcoming dates and locations

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