How do we use food scraps collected at home to create soil outside?
This Lesson Plan is part the Sustainability and Home modules of SustainEd Farms' virtual programming.
Background: Integrating Household Compost
In Compost I, the student was shown how to begin composting at home. Now that compost is collected, it is time to think about how to integrate household compost back into the garden. House-generated compost is likely to contain high amounts of “green” material (high nitrogen content) compared to “brown” material (high carbon content). For well-prepared compost, however, the ideal ratio of brown material to green material is about 2:1, which can be achieved with some forethought. It is also possible -- perhaps likely -- that the home composter, who may be collecting food scraps in something like a bucket, has been promoting anaerobic conditions (decomposition without oxygen). With such conditions, integration can become trickier since there is a longer decomposition time, there are potential toxins generated, and unwanted seed has not necessarily been killed off. With proper care, however, the gardener can promote aerobic conditions (decomposition with oxygen) for their compost pile, even with few materials and tools. In this lesson, the student will gain insight into preparing compost for eventual application in the garden.
Learning Objectives
Students will be able to...
Introduce their homemade compost to an outdoor pile for further breakdown
Understand and tend to the needs of a compost pile as the stewards of a microbiological community
Academic Vocabulary
aerobic /əˈrōbik/ adjective. - a process in which oxygen is involved
anaerobic /ˌanəˈrōbik/ adjective. - a process in which oxygen is not involved
Directions
1. Gather your materials. You will need the following supplies:
shovel · compost (food scraps from home + brown materials like bulky plant material, sawdust, corn stalks, leaves, straw, etc.) · water
2. Watch the following Youtube video to see a demonstration of how to integrate home-generated compost into a pit. Then, follow along with the remainder of the lesson by reading the steps below.
3. Locate an area in your yard, farm, or garden to dig several pits -- an area with good existing soil would be best. Using a shovel or other digging tool, dig a pit with at least a 1 ft depth. Adjust the depth, length, and width of the pit depending on how much compost is available. Dig 3 - 6 similarly sized pits in the same location.
4. If you desire to have each hole represent a “stage” in the decomposition process, empty food scraps from the home compost bin into one of the holes; if you desire to have many pits all decomposing at the same “stage,” scatter the food scraps equally among them. Choosing one method over the other does not have to be a be-all-end-all: consider whether or not a continuous supply of food scraps will be available (if they are available, having “stages” may be best to better judge how “ready” each pile is).
5. In each pit with compost, chop up the contents with a shovel and place a layer of dirt or soil over them. Mix the contents, and place another layer of soil over top.
🦠🔬Get the party started! … Integrating good soil -- that which has existing microbial life -- into your compost can help accelerate the process of breakdown.
6. Add a layer of “brown” organic materials to each pile with compost (consider gathering all of the bulky material of dead plants at the end of one season to use, or gathering dead leaves from a neighborhood). Chop and mix the material into the pile, and add another layer of dirt over top.
💭Recall from Compost I … the basic needs of a compost pile:
A moisture content of around 50% -- not too damp and not too dry!
Aeration to encourage the fast-acting aerobe (bacteria performing decomposition in the presence of oxygen, which is speedier, less odorous, and retains more nutrients)
A proper food source: nitrogen-high sources like food scraps will breakdown the high carbon stocks of brown materials like sawdust and cornstalks
7. If you live in a dry area, consider adding some water on top of your pile. Aerate (mix) the pile every few days, adding water when necessary. Monitor the pile for obtrusive smells: pungent, non-earthy smells may indicate that anaerobic processes are taking place, informing the compost tender that the pile may need to be ventilated better (if desired -- it will still decompose!). Pits, as described in this lesson, have a fundamental disadvantage in the “aeration” category simply because they are underground. However, they can introduce beneficial microorganisms to the pile very quickly, allow the pile to stay productive by keeping it warm in the winter and can retain needed moisture in the summer months.
8. After several weeks or months, the compost may be ready for application (see lesson titled Composting III). Some indicators of readiness include: a friable texture (crumbly appearance and tendency), a dark color, the ability to hold moisture at field capacity (as wet as a wrung-out sponge), no grease, a sweet and earthy smell, a temperature that matches the environment, and some not-yet-broken-down organic matter. Until then, continue to tend to the pile. At times, the pile may seem smelly, in which case you can add more carbon-rich brown content and aerate the pile more often. Don’t worry if the pile becomes very hot, as this is part of a natural progression in the composting process.
Additional Resources:
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