| name | composting-starter-guide |
| description | Sets up a home composting system from bin selection to first harvest, covering tumbler, static bin, and vermicompost options. Provides the green/brown ratio (3:1 brown:green by volume), troubleshooting for common problems (odor, pests, slow decomposition), and seasonal maintenance guidance for different climates.
Use when the user asks about starting a compost bin, composting food scraps, choosing a composting method, or troubleshooting compost problems.
Do NOT use for large-scale or commercial composting, biogas or methane digester systems, municipal composting program design, or using compost as fertilizer in a garden plan (use gardening skills).
|
| license | Apache-2.0 |
| metadata | {"author":"foundry-skills","version":"1.0.0","tags":"composting sustainability step-by-step guide","category":"sustainability","subcategory":"home-sustainability","depends":"","disclaimer":"none","difficulty":"beginner"} |
Composting Starter Guide
When to Use
Use this skill when:
- User asks about starting a compost bin or pile at home
- User wants to choose between composting methods (tumbler, bin, worm bin)
- User needs help with the green/brown ratio or compost ingredients
- User has a composting problem (smell, pests, not decomposing)
- User wants to reduce food waste through composting
- User asks what can and cannot be composted
Do NOT use when:
- User needs commercial or large-scale composting solutions
- User asks about biogas systems or methane digesters
- User wants to design a municipal composting program
- User asks about using finished compost in garden beds (use gardening skills)
- User asks about in-ground composting for specific soil types
Process
-
Assess the user's composting situation. Ask for:
- Housing type: house with yard, townhouse with small yard, apartment (balcony or indoor only)
- Space available: full backyard, small patio, indoor only
- Waste type: kitchen scraps only, kitchen + yard waste, primarily yard waste
- Volume: how much compostable waste per week (small: 1-2 gallons, medium: 2-5 gallons, large: 5+ gallons)
- Climate: hot/dry, temperate, cold winters, humid/tropical
- Experience level: never composted, tried and failed, some experience
- Budget: minimal (under $30), moderate ($30-100), flexible ($100+)
-
Recommend a composting method. Match the method to the situation:
Tumbler compost bin:
- Best for: house or townhouse with small to medium outdoor space, medium waste volume, users who want contained and neat composting
- How it works: sealed rotating drum. Add materials, spin the drum every 2-3 days to mix and aerate
- Timeline to finished compost: 4-8 weeks in warm weather with proper balance
- Pros: contained (fewer pest issues), easy to turn, relatively fast
- Cons: limited capacity (30-80 gallons), can get heavy when full, costs $80-200
- Volume capacity: handles 2-5 gallons of input per week
Static bin or pile:
- Best for: house with yard, large waste volume, users who also have yard waste
- How it works: pile or open-bottom bin on soil. Layer materials, turn with a fork every 1-2 weeks
- Timeline to finished compost: 3-6 months (active turning) or 6-12 months (passive)
- Pros: largest capacity, lowest cost (can be DIY), handles yard waste in bulk
- Cons: requires more space (3x3 ft minimum), more pest management, visible in yard
- Volume capacity: handles 5+ gallons of input per week
Vermicomposting (worm bin):
- Best for: apartments, indoor spaces, small waste volumes, kitchen scraps only
- How it works: red wiggler worms eat food scraps and produce worm castings (finished compost)
- Timeline to finished compost: 3-6 months for first harvest
- Pros: works indoors, compact (fits under sink or on balcony), odorless when managed correctly
- Cons: requires maintaining live worms, limited to kitchen scraps (no yard waste), cannot handle large volumes
- Volume capacity: handles 1-3 gallons of input per week per standard bin
- Starting worm population: 1 lb of red wiggler worms per square foot of bin surface area
Output Format
## Home Composting Setup Plan
### Composting Profile
| Parameter | Value |
|--------------------|------------------------------------|
| Housing type | [House / Apartment / Townhouse] |
| Space available | [Yard / Patio / Indoor only] |
| Waste volume | [Small / Medium / Large] |
| Climate | [Hot / Temperate / Cold / Humid] |
| Budget | [Minimal / Moderate / Flexible] |
### Recommended Method
| Feature | Your Setup |
|-------------------|-------------------------------------|
| Method | [Tumbler / Static bin / Vermicompost] |
| Bin type | [Description and size] |
| Location | [Where to place] |
| Starting cost | $[Range] |
| Capacity | [X gallons input per week] |
| Time to first compost | [X weeks/months] |
### Green/Brown Ratio Guide
| Add This (Green) | Add This (Brown) | Never Add |
|--------------------------|-------------------------------|--------------------|
| [Item 1] | [Item 1] | [Item 1] |
| [Item 2] | [Item 2] | [Item 2] |
| Target: 1 part | Target: 3 parts | |
### Setup Steps
1. [Step 1]
2. [Step 2]
3. [Step 3]
### Maintenance Schedule
| Task | Frequency | Notes |
|--------------------|---------------------|-----------------------|
| [Task 1] | [How often] | [Details] |
| [Task 2] | [How often] | [Details] |
### Troubleshooting Quick Reference
| Problem | Likely Cause | Fix |
|--------------------|---------------------|-----------------------|
| [Problem 1] | [Cause] | [Fix] |
### Estimated Impact
| Metric | Value |
|-----------------------|--------------------------------|
| Waste diverted | [X lbs/year from landfill] |
| Compost produced | [X cubic feet/year] |
| CO2e avoided | [X lbs/year] |
Rules
- NEVER recommend composting meat, dairy, oils, or pet waste in home composting systems -- these require industrial composting temperatures
- ALWAYS specify the 3:1 brown-to-green ratio by volume as the target balance
- The "wrung-out sponge" moisture test is the primary moisture guide -- compost should be moist but not dripping
- Worm bins must be maintained between 55-77F -- below 40F worms die, above 90F worms die
- Minimum pile size for thermal composting is 3x3x3 feet -- smaller piles will not generate sufficient heat for active decomposition
- ALWAYS include the "never compost" list to prevent pest and odor problems
- Never advocate for or against municipal composting policy -- focus on personal home composting setup
- Troubleshooting must address the five most common problems: odor, no decomposition, fruit flies, rodents, and slimy compost
- Climate-specific guidance must be included -- composting in Phoenix is fundamentally different from composting in Minnesota
- For apartment dwellers, vermicomposting is the primary recommendation -- outdoor methods require yard space
Edge Cases
-
User lives in an apartment with no outdoor space: Vermicomposting is the primary option. A worm bin fits under a kitchen sink or on a closet shelf. If the user is uncomfortable with worms, recommend community composting drop-off services if available in their area, or a countertop food scrap collector that can be emptied at a farmers market or community garden that accepts compost contributions.
-
User has tried composting and it smelled terrible: The smell almost always indicates too many greens and not enough browns. Walk the user through the 3:1 ratio correction. Have them add a thick layer of dry browns (shredded cardboard is readily available) and turn the pile. The smell should resolve within 2-3 days. Going forward, always add browns when adding greens.
-
User lives in bear or raccoon country: Use a tumbler or a bin with a locking lid and hardware cloth on the bottom. Never compost food scraps in an open pile in areas with large wildlife. Place the bin away from the house. In active bear areas, consider indoor composting (worm bin) instead, with outdoor composting limited to yard waste only.
-
User is in a cold climate with freezing winters: Composting does not need to stop in winter -- it just slows down. Continue adding scraps; they will freeze and decompose rapidly in spring. Insulate the bin with straw bales or a tarp. For worm bins, bring them indoors (garage or basement) when temperatures drop below 40F. Some users maintain a countertop scrap bin in winter and start outdoor composting in spring.
Example
Input: "I live in a house in the Pacific Northwest with a small backyard. My family of 3 produces about 3-4 gallons of food scraps per week. We already have a lot of dry leaves from the trees in fall. I've never composted but I want to start diverting our food waste from the trash. I'd rather not spend too much on this."
Output:
Home Composting Setup Plan
Composting Profile
| Parameter | Value |
|---|
| Housing type | House with small backyard |
| Space available | Backyard (small) |
| Waste volume | Medium (3-4 gallons/week food scraps) |
| Climate | Pacific Northwest (temperate, wet winters, mild summers) |
| Budget | Minimal to moderate |
Recommended Method: Static Bin
A simple static bin is the best fit for your situation: you have yard space, a good supply of dry leaves (browns), and medium waste volume.
| Feature | Your Setup |
|---|
| Method | Static compost bin |
| Bin type | DIY wire mesh bin (4 wooden pallets or hardware cloth cylinder) or purchased bin ($30-60) |
| Location | Back corner of yard, partial shade, on soil (not concrete) |
| Starting cost | $0-30 (DIY) or $30-60 (purchased bin) |
| Capacity | Handles 3-5 gallons of food scraps per week plus dry leaves |
| Time to first compost | 4-6 months with active turning; faster in summer, slower in winter |
Green/Brown Ratio Guide
Your target: 3 parts brown to 1 part green by volume
| Add This (Green -- 1 part) | Add This (Brown -- 3 parts) | Never Add |
|---|
| Fruit and vegetable scraps | Dry leaves (your main supply) | Meat, fish, or bones |
| Coffee grounds and tea leaves | Shredded cardboard boxes | Dairy products |
| Eggshells | Shredded newspaper | Cooking oils and fats |
| Fresh plant trimmings | Paper towels (unbleached) | Dog or cat waste |
| Grass clippings (thin layer) | Small twigs and stems | Diseased plant material |
Pacific Northwest tip: You have abundant dry leaves in fall. Bag them and store dry for year-round brown material supply. This is your single greatest composting advantage.
Setup Steps
- Choose a spot in partial shade, on bare soil, accessible with a path (you will visit it every few days)
- Build or place the bin. Minimum size: 3 ft x 3 ft x 3 ft
- Collect 3-4 bags of dry leaves if available (your year-round brown supply)
- Layer the base: 4-6 inches of dry leaves and small twigs
- Add your first batch of kitchen scraps (1-2 gallons). Spread evenly
- Cover with 3x the volume of dry leaves (this is the 3:1 ratio in action)
- Water lightly if the leaves are very dry (PNW rain usually handles this)
- Repeat each time you add scraps: food goes in, leaves go on top, always covered
Maintenance Schedule
| Task | Frequency | Notes |
|---|
| Add kitchen scraps + leaves | Every 2-3 days | Always bury scraps under browns |
| Turn pile with garden fork | Every 1-2 weeks | Mixes air in, speeds decomposition |
| Check moisture level | Weekly | Should feel like a wrung-out sponge. PNW rain may over-wet in winter -- cover with a tarp if needed |
| Harvest finished compost | Every 4-6 months | Compost is ready when it looks like dark, crumbly soil and smells earthy |
Troubleshooting Quick Reference
| Problem | Likely Cause | Fix |
|---|
| Smells bad | Too many greens, too wet | Add a thick layer of dry leaves, turn the pile |
| Not decomposing | Too dry or pile too small | Add water, ensure pile is at least 3x3x3 ft |
| Fruit flies | Exposed food scraps | Always bury scraps under 3 inches of leaves |
| Soggy in PNW winter | Too much rain | Cover with a tarp, leaving sides open for air |
| Rodents | Food exposed or prohibited items added | Ensure food is always buried; remove any meat/dairy if accidentally added |
Estimated Impact
| Metric | Value |
|---|
| Food waste diverted | 600-800 lbs/year (3-4 gal/week x 52 weeks) |
| Dry leaves composted | 400-600 lbs/year (your brown supply) |
| Compost produced | 4-8 cubic feet of finished compost per year |
| CO2e avoided | ~500-700 lbs CO2e/year (food waste in landfill produces methane; composting produces CO2 instead, which has ~25x lower warming impact) |
| Cost savings | Reduced trash bag usage; free compost for garden (worth $30-60/year if purchased) |
