Composting is a wonderful way to recycle food scraps and yard waste into nutrient-rich fertilizer for your garden. However, the downside is that composting can be a slow process, often taking several months for your compost pile to fully break down. If you’re eager to get your hands on that “black gold” for your vegetable beds and flower pots, using a compost accelerator is a great way to speed things up.
In this article, we’ll explore some of the best all-natural compost accelerators you can easily make at home. Forget questionable chemical concoctions – these DIY compost boosters use ingredients you likely already have in your pantry and yard. With just a little effort, you’ll soon have deliciously fertile, finished compost in half the time.
Why Use a Compost Accelerator?
Before we dive into the recipes, let’s look at why you might want to use a compost accelerator in the first place.
Composting relies on the right balance of carbon and nitrogen materials, moisture, and oxygen. It also requires the right mix of beneficial microorganisms such as bacteria and fungi to break down organic matter. A compost accelerator helps kickstart and feed these decomposing organisms to speed up the process.
More specifically, a good compost accelerator will:
- Add nitrogen: Decomposers need nitrogen to build proteins and reproduce. High-nitrogen ingredients feed microbes.
- Provide moisture: Bacteria thrive in damp conditions. Accelerators mixed with water moisten dry piles.
- Increase oxygen flow: Turning and aerating the compost allows air to circulate and oxygenate the decomposition process. Some accelerators help clump and break up compacted piles.
- Introduce microorganisms: Active bacteria, fungi, and other beneficial critters jumpstart the breaking down of organic materials in the compost.
By optimizing some of these key factors, you can slash your composting time in half or even by two-thirds!
Now let’s look at some of the easiest natural activators you can whip up at home.
1. Grass Clippings Compost Accelerator
Fresh grass clippings are a composting superstar. They add nitrogen, valuable enzymes, and tons of microorganisms to your compost pile. As a bonus, they break down quickly themselves.
Collecting and drying grass clippings is simple:
- Use your lawnmower bag to collect clippings after mowing your lawn. Dump them in a wheelbarrow or tarp to dry for 2-3 days.
- Alternatively, rake up decomposing grass under your lawn mower if you use a mulching blade and don’t collect clippings.
To use as a compost accelerator:
- Mix dried grass clippings into your compost pile, using them as your green/nitrogen layer.
- For a concentrated boost, combine 2 parts dried grass clippings with 1 part water in a bucket. After 2 weeks, strain the grass tea and sprinkle it over your compost.
The nitrogen, enzymes, bacteria, and fungi in grass clippings will kick your compost into high gear.
2. Manure Compost Accelerator
Manure from horses, cows, chickens, rabbits, and other livestock is excellent for accelerating compost. Animal manure provides a huge supply of nitrogen, microorganisms, and other nutrients to feed your decomposition team.
To collect manure for compost:
- Visit a local stable, petting zoo, or homestead and ask if you can take away manure. Offer to exchange it for some finished compost!
- For chicken manure, simply clean out your own coop. Rabbit and guinea pig manures also work great.
To use manure as an activator:
- Mix manure directly into your compost pile as a nitrogen layer. For quick compost, use manure for 25% of your pile.
- First compost the manure itself for 2 months to avoid harming plants with excess nitrogen. Then mix the finished manure compost into your pile.
Tip: Don’t use pet dog or cat feces which can transmit harmful bacteria and parasites.
3. Used Coffee Grounds Compost Accelerator
Coffee grounds offer a convenient kitchen compost accelerator. Their nitrogen jolts your compost microbes awake, while coffee’s acidity helps break down materials.
- Collect used coffee filters and grounds from your morning brews in a bin on your countertop or under the sink.
- Mix coffee grounds directly into your outdoor compost pile. They also make a fine substitute for part of your usual nitrogen layer.
- For a concentrated boost, steep grounds in water for a few days to make “compost coffee.” Strain and sprinkle over your pile. The released nutrients will supercharge your compost.
Tip: Don’t add more than 1 inch thick coffee grounds per day or they could temporarily lower your pile’s pH.
4. Seaweed Compost Accelerator
Seaweed from the ocean is packed with minerals, micronutrients, and beneficial marine microbes. Dried seaweed is an amazing compost activator.
To harvest seaweed:
- If you live near an ocean beach, collect seaweed at low tide. Choose broad kelps and brown seaweeds which grow in abundance.
- Alternatively, buy dried seaweed meal or kelp meal fertilizer online or at garden centers.
To use seaweed as a compost accelerator:
- Mix dried seaweed into your compost pile as part of your brown/carbon materials. It has a carbon to nitrogen ratio of about 20:1.
- For a nutrient kick, soak seaweed in water for 2 weeks. Dilute the seaweed “tea” 10:1 and sprinkle over your compost pile.
The 70+ minerals and elements in seaweed will encourage microbial diversity and faster decay in your compost.
5. Compost Starter Compost Accelerator
Compost starters are blends of active beneficial bacteria, fungi, and nutrients formulated to heat up your compost. You can purchase them, or easily make your own.
To make DIY compost starter:
- Add 2 cups finished compost to a 5-gallon bucket. This provides a balanced mix of microbes.
- Mix in 2 cups unsulfured molasses, which feeds microorganisms.
- Add 2 cups of compost tea or manure tea, which provides more bacteria.
- Fill bucket with water, agitate, and let sit 1-2 weeks until frothy.
To use your compost starter:
- Sprinkle compost starter over fresh compost materials as you build your pile.
- Pour it over your finished compost pile. The microbes will kick the decomposition into high gear.
- Add it to your compost pile every 2 weeks for an ongoing boost.
Tip: Store extra compost starter in a sealed container in a cool area. Refresh it yearly.
6. Bokashi Compost Accelerator
Bokashi is a Japanese fermented compost accelerator made from bran and beneficial microorganisms. You can purchase Bokashi bran, or easily make your own.
To make DIY Bokashi:
- Mix 5 parts wheat bran with 1 part rice bran or wheat germ. (Or use just wheat bran.)
- Sprinkle with 1 teaspoon each of compost starter and molasses per cup of bran.
- Optional: add 1 tbsp rock dust or kelp meal for extra minerals.
- Mix thoroughly and store in an airtight container out of direct sunlight.
To use Bokashi bran accelerator:
- Place food scraps in an airtight bucket, sprinkling each layer with Bokashi bran to inoculate it.
- Once full, set the sealed bucket aside to ferment for 2 weeks before burying in your compost.
The lactic acid bacteria in Bokashi softens and pickles materials before composting. It’s a great kitchen composting system.
7. Compost Tea Compost Accelerator
Compost tea is a nutritious tonic made by steeping finished compost in water. It’s brimming with beneficial microbes and soluble plant nutrients. Compost tea makes an excellent liquid accelerator.
To brew compost tea:
- Fill a 5-gallon bucket halfway with finished compost and the rest with non-chlorinated water.
- Agitate vigorously and let steep 3-7 days. Strain through cheesecloth or burlap.
- Use the compost tea immediately by sprinkling it over your pile.
The inoculation of diverse bacteria, fungi, protozoa, and nematodes in compost tea will boost your compost’s microbial activity and decay rate.
8. Urine Compost Accelerator
Surprise! Your own urine is full of concentrated nitrogen perfect for accelerating compost. As a free, fast-acting activator, it can’t be beat!
To use urine as a compost activator:
- Collect urine immediately, before it contacts toilet water, in a clean container. Or urinate directly around the outside edges of your compost pile.
- Dilute fresh urine at a 10:1 ratio before applying, to avoid burning plants.
- For a long-term stockpile, combine 1 part urine with 2 parts sawdust or straw to stabilize the nitrogen.
The urea in urine provides an immediate nitrogen boost. Limit urine to 1-2 cupfuls per application to prevent excess nitrogen.
9. Activated EM (AEM) Compost Accelerator
AEM stands for “activated effective microorganisms.” It’s an easy DIY compost inoculant using kitchen scraps.
To make AEM:
- Blend 1 part rice washed water with 2 parts molasses.
- Collect the mixture in a jar, cover with cheesecloth, and let sit 1-2 weeks.
To use AEM compost accelerator:
- Stir the AEM liquid and sprinkle it over your compost pile. Use 1 cup per cubic foot of compost.
- You can also mix AEM into your compost pile as you build it.
The lactic acid bacteria created during the fermentation process will accelerate decomposition in your compost.
10. Rock Dust Compost Accelerator
Rock dust provides a wide array of minerals that encourage microbial diversity and growth in your compost. Granite dust is especially beneficial.
To use rock dust as a compost activator:
- Mix 1 cup of rock dust per 1 cubic foot of compost as you build your pile.
- Alternatively, create a mineral tea by soaking rock dust in water for 2 weeks before sprinkling onto your compost.
With over 70 trace minerals and elements, rock dust gives your essential microbes the nutrition they need to thrive and speed up composting.
11. Wood Ash Compost Accelerator
Wood ash from stoves and fireplaces provides a concentrated dose of both minerals and alkalinity to your compost pile.
To use wood ash:
- Sprinkle thin layers of wood ash over compost materials as you build your pile.
- Limit ash to 5% of your total compost volume to prevent excess alkalinity.
The minerals and pH boost from wood ash will help energize microbial activity and speed decomposition.
12. Agricultural Lime Compost Accelerator
Agricultural lime raises pH, provides calcium for bacteria cell walls, and improves microbial function.
To use agricultural lime:
- Lightly dust new compost materials with agricultural lime as you build your pile.
- Limit to 2 cups lime per cubic yard of compost so as not to overload pH.
The improved pH and calcium will accelerate your compost and neutralize acids.
13. Worm Castings Compost Accelerator
Worm castings contain beneficial microbes and nutrients from worms’ digestive process. Castings are like a probiotic for your compost!
To use worm castings:
- Mix 1 cup worm castings per cubic foot of compost into your new materials as you build.
- Top dress existing compost piles with 1/2-1 inch of fresh castings.
The enzymes and microbes in worm castings give your compost pile the right biology for speedy decomposition.
14. Crushed Eggshells Compost Accelerator
Eggshells provide long-term released calcium carbonate to balance pH over time in your compost.
To use eggshells:
- Rinse eggshells, dry fully, and grind into a fine meal with a mortar and pestle or in a blender.
- Lightly sprinkle crushed eggshells over compost as you build your pile.
The steady pH buffering from eggshells creates an optimal environment for productive microorganisms.
15. Banana Peels Compost Accelerator
Surprisingly, banana peels act like a prebiotic for compost microbes. Their nutrients feed and increase beneficial bacteria.
To use banana peels:
- Chop peels into small pieces and mix directly into your compost pile as you build it.
- Mash peels into a pulp and add to compost for faster breakdown.
The prebiotics, potassium, and magnesium in peels serve as a probiotic for your compost ecosystem.
16. Unpasteurized Beer Compost Accelerator
The sugars and yeasts in non-pasteurized beer promote aerobic bacteria in your compost. Limit to smaller doses to avoid souring your pH.
To use beer as an activator:
- Pour 1 cup of flat, unpasteurized beer over materials as you build your pile.
- For quick breakdown, soak cardboard or paper towels in beer and bury them in your compost.
The yeasts and sugars will boost bacterial growth, accelerating decomposition. But don’t overdo it!
17. Pumpkin Puree Compost Accelerator
Pumpkins provide nutrients and a moist texture that kickstart microbe multiplication in your compost.
To use pumpkin:
- Blend or mash leftover pumpkin guts into a puree after carving jack-o-lanterns.
- Mix pumpkin puree into your compost pile as you build it.
The carbon, sugars, and moisture in pumpkin offer the perfect conditions for compost microbes to thrive.
18. Fruit and Vegetable Scraps Compost Accelerator
Fruits and veggies add a balanced dose of carbon, nitrogen, moisture, sugars, and acids to feed microbes.
To use fruit and veggie scraps:
- Bury produce scraps from meal prep and trimmings directly in your compost as you build your pile.
- Blend bumpy cucumbers, melon rinds, and citrus peels into a puree to accelerate breakdown.
The nutrition and moisture in produce scraps enhances microbial communities and propels faster composting.
19. Molasses Compost Accelerator
Molasses provides an easily accessible source of carbon and energy to boost bacterial and fungal growth.
To use molasses:
- Dissolve 1 part molasses in 4 parts water, and sprinkle this over your compost pile.
- Mix 1 tablespoon blackstrap molasses per gallon of manure or compost tea before brewing.
The sugars in molasses promote an explosion of microbial activity to speed up your finished compost.
20. Alfalfa Meal Compost Accelerator
Alfalfa is a legume that fixes nitrogen from the air into plant-available forms that feed composting microbes.
To use alfalfa:
- Sprinkle 1 cup alfalfa meal per 1 cubic foot of compost onto materials as you build your pile.
- Brew bagged alfalfa tea according to package instructions and pour over your finished compost.
The nitrogen and growth promotors in alfalfa encourage microbial diversity and accelerate decomposition.
21. Cottonseed Meal Compost Accelerator
Cottonseed meal provides a slow-release source of nitrogen and carbon that steadily feeds microbes over time.
To use cottonseed meal:
- Mix 1 cup cottonseed meal per 1 cubic foot of compost into materials as you build your pile.
- Create a nitrogen tea by steeping cottonseed meal in water for 1-2 weeks before using.
The gradual nitrogen release prevents burnout while sustainably feeding compost microbes.
22. Bone Meal Compost Accelerator
Bone meal offers an excellent source of steady, long-term phosphate, nitrogen, and calcium to nourish composting microorganisms.
To use bone meal:
- Mix 1 cup bone meal per 1 cubic foot of compost into your pile as you build it.
- For a concentrated boost, steep bone meal in water for 2 weeks and use the “tea” to soak compost.
The slowly available nutrients in bone meal provide nourishment over time for your compost ecosystem.
23. Kelp Meal Compost Accelerator
Kelp meal made from dried seaweed contains over 60 minerals and growth promoters that benefit your compost food web.
To use kelp meal:
- Sprinkle 1 cup kelp meal per 1 cubic foot of compost onto materials as you build your pile.
- Soak kelp in water for 2 weeks, and spray the nutritious kelp tea onto finished compost.
The wide array of minerals and nutrients in kelp meal energize and feed diverse compost microbes.
24. Inoculant Compost Accelerators
Finally, consider commercial inoculants that amplify specific composting microorganisms when you build a new pile:
- Bacterial inoculants like MooDoo or PooDoo introduce key bacteria varieties that initiate decomposition.
- Fungal inoculants like MycoBloom provide specialized fungi to break down woody materials.
- Biodiversity inoculants like EM-1 introduce a blend of 80+ microbes to fully populate your compost’s food web.
Follow package instructions carefully. A biodiversity inoculant plus one other activator may offer the best results. With the right microbial army, you’ll be harvesting finished compost in record time!
Tips for Using Compost Accelerators
Now that you know what to add to speed up compost, here are some quick tips on how to use activators for maximum effect:
- Only use compost accelerators when building a brand new compost pile. They’ll be ineffective on finished, curing compost.
- Mix, sprinkle, or layer accelerators throughout the entire pile rather than dumping only on top.
- Limit strong nitrogen accelerators like manure and urine to thin layers to avoid burning plants with excess nitrogen later.
- For dry piles, always moisten materials when adding dry activators like alfalfa meal or rock dust.
- Turn and mix your actively composting pile after adding accelerators to incorporate them fully.
- Cover your compost during wet weather to prevent activators from washing away.
Follow these best practices, and your accelerators will work their natural magic on your compost!
Signs Your Accelerators Are Working
How can you tell if your chosen compost accelerators are speeding things up? Here are some clues:
- Hotter temperatures – Accelerated compost can reach 140-160°F, killing pathogens and weed seeds. Use a compost thermometer to monitor internal heat.
- Visible shrinking and settling – Materials rapidly breaking down will show your compost pile shrinking down week by week.
- Sweet, earthy smell – The smell will change from sour/ammonia to a sweeter, dark soil scent.
- Darker color – Browns and greens will fade to dark brown or even black as the compost matures.
- Abundant white mycelium – White fungal threads through compost are a good sign microbes are thriving.
- Clumping texture – Finished compost will have a crumbly, moist, clumped texture without recognizable materials.
When your compost shows these signs after just 4-6 weeks, you’ll know your accelerators have been effective!
Make Your Own Compost Activator Blend
For the fastest compost ever, I recommend making your own super-powered compost activator blend. Just mix:
- 2 parts grass clippings
- 2 parts manure compost
- 1 part used coffee grounds
- 1 part molasses
- 1 handful each of crushed eggshells, rock dust, and dried seaweed
Sprinkle this blend into your new compost pile, and watch your compost transform in no time!
You can adjust the ingredients based on what you have available. I like to make a big batch of my super activator so I always have some ready to speed up the next pile.