What is a Composting Garden Bed?
A composting garden bed is a raised bed that allows you to compost kitchen scraps and yard waste directly in the garden where your plants are growing. It combines the benefits of raised bed gardening with the nutrient-boosting power of compost. The basic design includes an open area in the center of the raised bed for adding compostable materials. As the compost breaks down, it releases nutrients into the surrounding soil to feed your plants. You can grow vegetables, herbs, or flowers in the planting areas around the compost section.
Benefits of Composting Garden Beds
Composting garden beds offer several advantages for gardeners:
Convenience
Composting garden beds simplify the composting process by allowing you to compost directly where you’re growing your plants. This eliminates the need to maintain a separate compost bin or pile and transport the finished compost to your garden.
- You can easily add kitchen scraps, yard waste, and other organic materials to the compost section of your raised bed whenever you have them available.
- No need to worry about finding a suitable location for a compost pile or bin that’s the right distance from your house and garden.
- Composting and gardening in one spot saves time and effort, making it easier to stick with the practice.
Nutrient-Rich Soil
Compost is often called “black gold” for gardeners because of its incredible soil-enhancing properties. As the compost in your garden bed breaks down, it releases a wide array of nutrients that feed your plants.
- Compost contains essential plant nutrients like nitrogen, phosphorus, and potassium, as well as micronutrients like iron, manganese, and zinc.
- The nutrients in compost are slowly released over time, providing a steady supply of nourishment to your plants throughout the growing season.
- Compost also helps the soil retain these nutrients, reducing the need for additional fertilizers.
- Plants grown in compost-rich soil are typically healthier, more productive, and more resistant to pests and diseases.
Water Retention
Compost acts like a sponge in the soil, absorbing and holding onto water that would otherwise drain away or evaporate.
- Compost can hold up to 20 times its weight in water, which helps keep the soil consistently moist.
- This means you may need to water your plants less frequently, saving time and conserving water resources.
- The improved water retention also helps plants survive and thrive during periods of drought or inconsistent rainfall.
Improved Soil Structure
In addition to providing nutrients and retaining water, compost also improves the physical structure of the soil over time.
- Compost helps bind together sandy soils, improving their ability to hold water and nutrients.
- In heavy clay soils, compost breaks up compacted particles, allowing for better drainage and aeration.
- The improved soil structure promotes healthy root growth, allowing plants to access more water and nutrients.
- Better soil structure also makes it easier for beneficial soil organisms like earthworms and mycorrhizal fungi to thrive, further enhancing soil health.
Raised Bed Advantages
Composting garden beds also offer the general benefits of raised bed gardening, which include:
- Better drainage: Raised beds allow excess water to drain away from plant roots, preventing issues like root rot and fungal diseases.
- Earlier planting: The soil in raised beds warms up faster in the spring, allowing you to plant earlier and extend your growing season.
- Easier access: Raised beds bring the planting surface closer to you, reducing the need to bend or kneel and making gardening more comfortable.
- Fewer weeds: The raised design and dense planting in raised beds can help suppress weed growth.
- Protection from pests: Some raised beds include features like fencing or netting to keep out pests like rabbits or deer.
By combining the benefits of composting with the advantages of raised bed gardening, composting garden beds offer a convenient, efficient, and productive way to grow healthy plants while recycling organic waste.
How to Use a Composting Garden Bed
Here are more details on how to use a composting garden bed:
1. Gather Composting Materials
Collect a mix of brown and green organic materials to layer in your composting garden bed.
- Browns (carbon-rich) – aim for about 3 parts browns:
- Dry leaves
- Straw or hay
- Shredded newspaper or paper
- Sawdust or wood chips
- Twigs and small branches
Greens (nitrogen-rich) – aim for about 1 part greens:
- Fruit and vegetable scraps
- Coffee grounds and tea bags
- Fresh grass clippings
- Plant trimmings from your garden
- Eggshells
Avoid meat, dairy, oils, diseased plants, weeds with seeds, and pet waste which can attract pests or spread disease.
2. Layer Browns and Greens
Start your compost pile with a 4-6 inch layer of browns at the bottom of the composting section of your raised bed. This will help absorb excess moisture and provide aeration.
Add a 2-3 inch layer of greens on top of the browns. The nitrogen-rich greens will help activate the composting process.
Continue alternating layers of browns and greens until your composting area is full or you run out of materials. Aim for a 3:1 ratio of browns to greens.
3. Add Water
Moisture is important for the composting process. The materials should be damp but not soaking wet.
Use a hose or watering can to moisten the layers as you build the pile. The compost should feel like a wrung-out sponge – moist but not dripping wet.
If the pile gets too wet, mix in some more dry brown materials. If it’s too dry, add water.
4. Mix and Turn
Turning the compost introduces oxygen which is essential for the decomposition process. It also helps distribute moisture and mix the materials for faster, more even composting.
Use a pitchfork, compost aerator tool, or garden fork to mix the layers and turn the pile every 1-2 weeks.
Insert the tool deep into the pile and lift and fluff the materials. Break up any clumps and move materials from the center to the outside so everything gets mixed together.
5. Monitor and Maintain
As you add new materials to the pile, try to maintain the 3:1 ratio of browns to greens. Alternate layers and mix in the new additions.
Keep an eye on the moisture level and add water if needed. The pile will shrink down as materials decompose.
You can use a compost thermometer to track the temperature of the pile. It should reach 130-150°F at the center for the fastest composting.[5] If it doesn’t heat up, there may be too much brown material. Mix in some more greens.
6. Harvest Finished Compost
Depending on your conditions and materials, you should have finished compost in 2-6 months.
Finished compost will be dark brown, crumbly, and smell earthy like soil. It should no longer heat up when turned.
You may still see some chunks of materials that haven’t fully broken down. You can sift these out and add them back to a new batch of compost.
7. Use Compost in Your Garden
Spread a 1-3 inch layer of finished compost on top of the soil around your plants. You can lightly mix it into the top few inches of soil or leave it as a mulch.
Compost will slowly release nutrients to your plants, improve soil structure, help retain moisture, and support beneficial organisms.
Add compost to your garden beds at the beginning of each growing season or between crop rotations. You can also use it as a mulch throughout the season.
By following these steps to compost directly in your raised garden beds, you can create a convenient and efficient way to recycle organic waste, build healthy soil, and nourish your plants.
Tips for Success
Chop Materials into Small Pieces
The smaller the pieces of organic matter you add to your compost, the faster they will break down.
- Chop or shred leaves, twigs, and plant trimmings into 1-2 inch pieces before adding them to the pile.
- Cut up fruit and vegetable scraps into small chunks rather than adding whole items.
- Tear or shred newspaper and cardboard into strips before composting.
Smaller particles have more surface area for microorganisms to work on, which speeds up the decomposition process. Aim for materials that are about the size of a dime or smaller.
Avoid Adding Certain Materials
Some organic materials can cause problems in your compost pile and should be avoided:
- Meat, fish, and bones: These items can attract pests like rats and raccoons, and may also create odors as they decompose.
- Dairy products: Like meat, dairy can attract pests and cause odors. It can also upset the moisture balance in your compost.
- Oils and fats: Greasy materials can coat other items in the pile and slow down decomposition. They may also attract pests.
- Diseased plants: Plant material with fungal or bacterial diseases can spread those pathogens to your finished compost and infect your garden plants.
- Weeds with seeds: Weed seeds can survive the composting process and spread when you use the compost in your garden.
- Pet waste: Dog and cat feces can contain harmful bacteria and parasites that may not be killed during composting.
Stick to vegetable scraps, yard waste, paper products, and other non-hazardous organic materials for the safest and most effective composting.
Keep a Stockpile of Brown Materials
It’s a good idea to keep a supply of carbon-rich brown materials on hand to mix with your green food scraps and garden waste.
- Collect dry leaves in the fall and store them in a bin or bag near your composting garden bed.
- Save paper products like shredded newspaper, paper towels, and cardboard to add to the pile as needed.
- Stockpile straw, sawdust, or wood chips to use as a brown layer.
Having a ready source of browns makes it easy to maintain the proper ratio of carbon to nitrogen in your compost pile, which is key for efficient decomposition.
Bury Food Scraps
When adding kitchen scraps to your composting garden bed, it’s best to bury them under a layer of brown materials.
- Dig a small hole or trench in the center of your compost pile and add the food scraps.
- Cover the scraps with a layer of dry leaves, straw, or shredded paper.
- Mix the layers a bit with a fork or compost turner.
Burying food waste helps to:
- Deter pests like flies, rats, and raccoons that may be attracted to the scraps.
- Reduce any odors from decomposing food.
- Speed up the composting process by surrounding the scraps with carbon-rich materials.
Maintain Proper Moisture
The microorganisms that break down your compost need the right amount of moisture to thrive.
- The compost should be about as damp as a wrung-out sponge – moist but not soaking wet.
- If the pile is too dry, use a hose or watering can to moisten it thoroughly.
- If the pile is too wet and soggy, mix in some more dry brown materials like leaves or straw to absorb the excess moisture.
Proper moisture helps to:
- Support the beneficial bacteria and fungi that decompose the organic matter.
- Distribute nutrients and microorganisms throughout the pile.
- Prevent the compost from becoming compacted and anaerobic.
Aim to maintain consistent moisture throughout the composting process for the fastest and most effective results.
Monitor the Temperature
The temperature of your compost pile is a good indicator of how well the decomposition process is going.
- As microorganisms break down the organic matter, they generate heat.
- A well-maintained compost pile should reach temperatures of 130-150°F at its center.
- Use a compost thermometer to check the temperature of your pile regularly.
If the pile is not heating up:
- It may be too dry – add water until it’s evenly moist.
- It may need more nitrogen – mix in some green materials like fresh grass clippings or food scraps.
- It may be too small – add more volume to the pile to help it retain heat.
If the pile is too hot (over 160°F):
- It may be too wet – turn the pile and mix in some dry brown materials.
- It may need more oxygen – use a compost aerator tool or garden fork to turn the pile and introduce air.
Maintaining the right temperature range will speed up the composting process and ensure that weed seeds and pathogens are killed by the heat. By following these tips for chopping materials, avoiding problematic items, stockpiling browns, burying food scraps, maintaining moisture, and monitoring temperature, you can create the optimal conditions for fast, efficient composting in your garden bed.
Composting Garden Bed Products
Some popular composting garden bed kits and designs include:
Vita Classic 8×12 Keyhole Composting Garden
The Vita Classic 8×12 Keyhole Composting Garden is a large raised bed that combines composting and gardening in one convenient system.
Key features:
- Dimensions: 144.25″ L x 97.13″ W x 46.75″ H
- Planting area: 65 sq ft
- Soil capacity: 108 cu ft
- 4 central compost baskets for adding kitchen scraps
- Raised foldable fence panels (22 7/8″ high) with slide latch for easy access and plant support
- Gate for keeping pests out
- Made from food-grade, BPA-free, phthalate-free vinyl
- 10-year limited warranty on vinyl components, 1-year on mesh fencing
- Requires minimal watering and no soil turnover
- Easy to maintain and clean
- Modular design allows for custom configurations
Benefits:
- Large capacity for growing vegetables, herbs, fruits, and flowers
- Tall raised beds eliminate bending and kneeling
- Composting and gardening in one system for nutrient-rich soil
- Fencing supports plants and keeps animals out
- Durable, food-safe materials for long lifespan
- Efficient water and soil usage
Garden Tower 2 Composting Container Garden
The Garden Tower 2 is a vertical composting garden that allows you to grow 50 plants in just 4 square feet of space.
Key features:
- Dimensions: 43″ tall, 24.5″ wide
- 50 planting pockets arranged in a spiral pattern
- 6 cubic feet of growing media capacity
- Central composting core for kitchen scraps
- Removable compost tea drawer to collect liquid fertilizer
- Rotates 360 degrees for even sun exposure
- Made from 100% food-grade, UV-stable HDPE plastic in the USA
- 5-year manufacturer warranty
- Weighs 36 lbs empty, ~220 lbs planted
- Optional caster kit for mobility
Benefits:
- Grows a high number of plants in a tiny footprint
- Vertical design is accessible and space-efficient
- Composting core recycles nutrients for plants
- Rotation ensures all plants get adequate light
- Durable, food-safe construction
- Produces both solid and liquid organic fertilizers
- Great for patios, balconies, rooftops, and urban gardens
DIY Keyhole Garden
A keyhole garden is a circular raised bed with a central compost basket that you can build yourself using various materials.
Typical features:
- 6-8 feet in diameter
- 3-4 feet high walls made of wood, stone, concrete blocks, or other materials
- Compost basket in the center, about 12″ in diameter and the same height as walls
- Wedge-shaped cutout for easy access to compost basket
- Layers of organic materials (cardboard, sticks, straw, compost, soil) to fill the bed
Construction steps:
- Mark out a circle and central compost basket location
- Build the outer walls and compost basket
- Create the access cutout
- Fill the bed with layers of organic materials
- Plant crops around the compost basket
- Add kitchen scraps to the basket throughout the growing season
Benefits:
- Inexpensive materials
- Customizable size and design
- Efficient composting and water usage
- Accessible bed with minimal bending
- Nutrient-rich soil feeds plants
- Fun DIY project
Whether you choose a ready-made kit or build your own, a composting garden bed is an excellent way to create a productive, sustainable, and low-maintenance growing system. By recycling kitchen scraps into compost right in the garden bed, you can nourish your plants, reduce waste, and enjoy fresh, homegrown produce.
Final Words
Whether you purchase a kit or build your own, a composting garden bed is an efficient way to recycle waste, nourish your soil, and grow healthy plants. With the convenience of composting and gardening in one spot, you can enjoy the many benefits of this sustainable growing method.