Compost is called The Gardener’s Gold because it’s an invaluable partner in keeping the soil healthy. In organic gardening, making compost is part of the gardener’s To-Do List every growing season.
If you’re thinking of using compost that you made yourself instead of buying it from your favorite garden store, here are seven simple things to remember before you start going crazy making compost.
#1 What Compost is NOT
Compost is a wonderful recycling facility right at your home. Food scraps need not go to the landfill anymore but you can use it in your garden as organic soil improver. Your soil will love you for it!
But for all its wonderful benefits, compost isn’t meant to be used a fertilizer. It’s relatively low in nutrients that plant need to grow healthy and robust.
What compost does well though is help improve soil structure, prevent the growth of weeds, and regulate moisture in the soil. Most importantly, compost teems with microbial life—good microorganisms that keep the soil healthy and make nutrients readily available to plants.
(One caveat though: For those who’re looking to compost as a source of mycorrhizae, compost very rarely contains enough mycorrhiza. You’d have to physically add mycorrhizal fungi in spore form, not the hyphae that you get from old roots or soil.
The old school way of adding mycorrhizae to new plants involved digging up soil from areas known to contain them, like compost from virgin forest floors. But then, this could only have ectomycorrhizae, and rarely endomycorrhizae. Today, you can buy professional-grade mycorrhizal products that have both ecto and endomycorrhizae so you don’t waste time deciding which fungi goes with what plant.
For a more extensive discussion on mycorrhizal benefits, read our post on mycorrhizae.)
#2 What to Consider Before Making Compost
Where you will place your compost bin or compost pile and how large your compost heap will depend on many things:
- The amount of space you have in your garden for composting
- The kind of materials you will be using to make compost
- How you will use compost and how much
- The time and effort you’ll spend making compost, and
- How you’ll keep your compost pile spic and span
Decide on these things first before you start making compost so you won’t face a bigger problem down the line. You may find one day that you’ve made way too big a compost bin when you only have a small source of organic material to build on. (In which case, your compost will take a long time getting ready.)
#3 What Happens When Making Compost
Making compost is like fermenting beer: you need bacteria, air, moisture and warmth so magic—the breakdown of compost ingredients—can happen.
Keep in mind the following when you start making your compost:
- Microbes are responsible for digesting or decomposing compost ingredients like the kitchen scraps, grass clippings, twigs, and other materials that you’re using.
- When the compost pile starts to heat up, that’s when the microbes are hard at work, breaking down organic materials. (Heat is the energy given off when microbes start digesting the carbon compounds in the compost heap.)
- The compost heap can get as hot as 170 degrees Fahrenheit.
- When the compost pile cools down, it may mean two things: (1) composting is complete, or (2) anaerobic organisms have taken over your compost pile…which means you need to mix the pile to keep oxygen circulating enough to encourage aerobic microbes to start working again.
- Compost starts heating up two days after you’ve started your pile.
- Turn your compost pile every 2 or 3 days to let air circulate and speed up the decomposition of organic materials. Alternatively, you can wedge a PVC or steel pipe riddled with holes in the center of the compost so air can get through the heap.
- Cover the compost heap to protect it from rain. Too much water ferments the decomposing materials, which can stink to high heavens if you’re not careful.
- A smaller compost heap is easier to manage, neater and will decompose much more quickly than a larger pile. Composting materials all at once will also help speed up composting time.
#4 What Goes Into Making Compost
Anything that once lived is potential compost material. I say “potential” because there are some materials that you can’t use, for simple health or practical reasons.
The best compost is a mixture of “green” and “brown” materials.
“Greens” are young, sappy materials that rot quickly and are high in nitrogen like:
- Grass clippings
- Poultry manure, especially strawy animal manure
- Young weeds and plants
- Fruit and vegetable scraps
- Fish meal
- Coffee grounds
- Alfalfa meal
- Tea bags and tea leaves
- Cut flowers
- Soybean meal
- Bedding from herbivorous pets
“Browns” are organic materials made from tougher materials, have usually dried, and are high in carbon, like:
- Fall leaves
- Spoiled hay / old straw
- Wood chips
- Egg cartons
- Shredded newsprint and office paper
- Shredded tree barks
- Paper bags and paper towels
Experts suggest a 30:1 ratio of carbon to nitrogen organic materials when making compost.
#5 What NOT to Compost
There are materials that aren’t suitable to making compost.
One, because they simply don’t decompose and will still be there whole when the rest of the composted material is ready. These materials include plastic, Styrofoam, glass or metal.
Two, they may spread diseases and harmful pathogens like dog feces, used cat litter and disposable diapers.
Three, because they encourage unwanted visitors like rodents and deer to rummage in your compost because they’re attracted to the compost’s nasty smell. Things like animal bones, fat, meat and fish scraps, greasy items, and other dairy products fall in this category.
#6 Compost is Ready When…
…it has turned into dark soil and you can’t recognize the original ingredients anymore. (Although sometimes, you’ll see the odd bark, twig or egg shell in it).
If you start making compost in late spring or early summer, the heat helps to quicken composting time to as little as 12 weeks. In the fall, if you’re composting a large pile, your composting materials are mostly slow-rotting, or you’re not mixing the compost heap often, compost can take up to a year—sometimes even two years!—to be ready.
Most experienced gardeners and commercial growers have discovered though the secret of using compost activators – the professional type with real biology specifically designed for composting.
Some call them compost starters but the principle is the same: they add specially selected microbial species to the compost pile so that these beneficial microorganisms can start working on making compost immediately.
Shameless plug: AgVerra manufactures a professional grade Compost Activator product through its SoilNoc brand.
A billion microbes prime the compost material so that it starts heating up immediately. Customers who have used the Compost Activator report that they start using compost as early as 60 days from the time they start making compost. Some has even reported a 30-day composting process.
(You can purchase the Compost Activator from AgVerra’s online store here and have it delivered at your doorstep in as little as 3 days.)
#7 How To Use Compost
If compost is not a fertilizer, then how do you use it?
Considered as a medium-fertility soil improver, compost is used as mulch in spring or summer to regulate moisture and prevent evaporation so plants don’t starve during a drought.
How much compost you use depends on the soil’s fertility and structure.
Experienced gardeners spread about 2 to 4 inches of compost on their garden beds or incorporate it 8 inches into the topsoil every year, some even twice a year.
In the fall, a rule of thumb when the soil needs a fertility boost or structural improvement is to dig in 12-18 inches and mix half-decomposed material into the soil. In the winter, the half-composted material will have decomposed fully and would’ve added the much needed soil amendments in time for spring sowing.
Making compost isn’t difficult at all, and is well worth the effort because gardening is one endeavor where you can literally see the fruits of your labor!
Next time, we’ll discuss the different composting methods that are available out there (yes, there are several!). In the meantime, if you’ve been composting or you’ve just started making compost, share with us your stories in the comments section below.