3 Easy Composting Options for Small Gardens
If you have a small garden, you don't need to build a large, hot pile to create great compost. This article describes three composting options for small yards.
How Much Compost Do You Need?
If you have a small garden, probably much less than you think! Once you have improved your garden soil over the first 2-3 years, you usually don't need to add more than 1/4″ of compost to your garden each year.
If you keep adding large amounts of compost, manure, or mulch to your garden year after year, you can cause serious nutrient imbalances in your soil. This is one of the long-term hazards of gardening with Mel's mix (square foot gardening potting soil), because it decomposes rapidly and you have to keep adding large amounts of compost every year to keep your garden beds full of soil. You have the same risks if you garden with deep permanent mulch for many years.
So, how much compost does a small 4′ x 4′ garden bed need? (One with real mineral soil, and not Mel's mix.) Only 1/3 cubic foot per year (about 1/2 of a five-gallon bucket). Three of these beds together need only one 40-lb bag of compost – just one cubic foot (1 1/2 five-gallon buckets).
Creating compost using a standard hot composting method involves building a large compost pile all at once, with the right balance of “brown” and “green” ingredients. A good size for hot composting is 4′ x 4′ x 4′ high. This is a large amount of material – about 100 5-gallon pails! That takes a lot of work and space. By the time this size pile finishes composting, you'll have at least 16 cubic feet of compost – enough for 48 small garden beds!
It's a great way to compost, but it's overkill for small gardens.
Here are three composting options for small gardens:
1) Use Mulch (a form of sheet composting)
If your climate is suited for it (hot summers, cold winters), keeping a thin layer of mulch on your garden beds will add plenty of organic matter – your compost will be created in place. Lawn cuttings are my favorite mulch, and my earthworms love it, too! You can also use shredded leaves, if you want. (To learn more, read: My Lawn is My Garden's Best Friend.)
Straw and hay are more possibilities, but there are 3 possible issues with them:
- the long-stemmed material can be difficult to use around densely planted small plants, like carrots
- there is a risk of contaminating your garden with long-lasting herbicides (see Don't Kill Your Garden with Compost)
- they are often full of grain or weed seeds
Whatever type of mulch you choose, just be sure to not use a thick layer. With lawn cuttings or shredded leaves, you only need 1-2 inches, just enough to protect the surface of the soil and reduce weed growth. Coarser mulch, like straw or hay, needs to be a little deeper. Mulch that is too deep will prevent brief rainfalls from reaching the soil, and can create nutrient-imbalances in your garden over the long-term.
2) Create Leaf Mold
Leaf mold is just decomposed leaves. This is a lazy, but slow way, to create great compost. Just take your autumn leaves, wet them thoroughly, and then pile them up and wait. Shredded leaves will rot faster. You don't need to create a large pile, as this is a cold composting method that doesn't need a large volume.
You can stomp on the wet leaves to compact them as you build the pile – they don't need extra oxygen to decompose, because fungi does most of the work in decomposing leaves. Then wait 1-2 years, while keeping the pile moist. It will shrink to about 1/3 of the starting size when it's done. Sift out any twigs or stems, and you're good to go!
If you start with a tiny 2 foot x 2 foot x 2 foot high well-compacted pile of moist leaves, it can create enough compost for 6-8 small 4′ x 4′ garden beds.
3) Make Vermicompost
This is composting by using earthworms, and it can be a great way to deal with kitchen scraps without attracting animal pests, such as rats or skunks. Research has showed that vermicompost is even more beneficial for our garden plants than compost created in conventional hot piles.
There are a wide variety of commercial or homemade worm bins available. See Cheap and Easy Worm Bin! for one homemade option. My sister and I were able to buy an affordable used Worm Factory Composter from our local Craigslist, and it has worked out very well in our basement.
In fact, our worm population has multiplied so much that we've now created a large worm bin in a corner of our hoop house. It's 3 foot x 4 foot x 20 inches high. We filled it full of a mixture of shredded leaves, grass cuttings, chicken manure, kitchen scraps, and a little bit of soil. We could have used torn up newspaper and cardboard, too.
After we thoroughly moistened the ingredients, it heated up because we had added so many high-nitrogen ingredients. They weren't necessary for vermicomposting, but were just extra material that we wanted composted, too. Once the bin cooled down again, we added the worms. We keep adding kitchen scraps every week, and occasionally more bedding material.
This bin will provide enough compost for up to 20 small garden beds, but we'll probably use most of it for starting seedlings and adding to our containers. We should be able to harvest at least 1/3 of the bin every 3-4 months during the warm season.
We'll be able to use this bin year-round, as the temps in our hoop house rarely drop below the mid-20's and the bin is large enough to provide a warm spot for the worms during cold snaps. Some people in cold climates create worm bins below ground, but that only works if your soil is well-drained (ours isn't). You also need to keep moles from tunneling into outdoor bins and feasting on your worms. You can use 1/2″ hardware cloth (metal screening) at the bottom. We have a thick layer of crushed stone under our outdoor worm bin.
Just be aware that this is not a dump and forget method of composting! Worms are living creatures that need proper care – including maintaining correct moisture levels, giving them fresh food on a regular basis, and periodically providing new bedding.
Use What Works Best for You
My sister and I actually use all three methods, but we have a larger garden than most people – 500 square feet of vegetable beds, 350 square feet of fruit beds, and a lot of containers. In addition, we have a “dump and forget” compost pile for larger garden debris. It's a slow, cool compost pile that may take over a year to decompose, but we're not in a hurry and we enjoy not having to turn it regularly. However, it doesn't produce high-quality compost.
What methods have you used for composting in a small yard? Care to share?