Gardening Compost Is Free. Why Not Use It?
When talking about “gardening compost”, we mean “decayed organic material that can be used to fertilize a garden.”
The word, compost, also describes the normal means of decomposition of organic material by aerobic bacteria into a rich soil mulch to enrich your growing experience naturally.
So, What Can Be Used In A Compost Pile?
Compost needs a concoction of four basic elements in a delicate balance to make the decomposition process happen.
- Dry and brown ingredients add carbon for producing heat energy. These element include leaves, dry grass, small branches, dry plant trimmings, dry cornstalks, straw, sawdust (from untreated wood), newspaper (black and white preferably…color dyes are not good for compost), unbleached napkins (make sure they do not contain any chemicals or non-organic ingredients), used coffee filters, etc.
- Moist and green ingredients introduce nitrogen to foster organism growth responsible for oxidizing the carbon. Satisfy this need with freshly cut grass and healthy garden plants that have reached the end of their producing cycle. Throw in some organic foodstuffs that include any vegetable or fruit throw-aways; peelings, stems, seeds, cores, rind…you get the picture. Eggshells (preferably rinsed) and coffee grounds add their own nutrients, too, as well as helping to open up the pile for aeration. Bottom line…if it has ever grown in a field, it can be composted!
- Oxygen is needed to facilitate the decay process and should be periodically mixed through the compost pile by turning the compost every couple of weeks.
- Water helps to maintain the breakdown activity as long as the pile stays moist…but, not soggy wet.
TIP: Chop up both dry/brown items and moist/green item as much as possible to facilitate the decaying process. The smaller the chunks added to a compost pile…the quicker and easier it is to encourage decay and oxygenation. I use a lot of leaves in my compost pile since I have an abundance of them every year just as most home owners do…so, I bag them for dry/brown use throughout the growing season…after first mulching them with my lawn mower.
Never…Ever…Add These Things To Your Compost Pile!
There are a number of foods that will destroy a compost pile by introducing unwelcome anaerobic bacteria…the enemy of the good aerobic bacteria. Aerobic bacteria are essential to breaking down the organic material in your compost.
These foods may also add extremely pungent odors and attract unwanted critters such as raccoons, rats, and mice, to name a few.
And, if the rats and mice show up, snakes will soon follow because they want to be close to their prime food source.
- BBQ coal ash – This type of ash contains a tremendous amount of sulfur oxides. However, wood ash from untreated wood in small quantities can be added to a compost pile.
- Cooking oil – This oil not only sends out “open for business” food invitations to both animal and insect pests, it will wreak havoc on the moisture balance of a compost pile.
- Colorful or coated paper – The more colorful paper is…think magazines…the more printing chemicals have been used to create the vivid colors. You don’t want these chemicals destroying the carefully crafted compost you create! And items like aluminum foil will not break down so, leave it out, too!
- Dairy products – If you try to compost milk or cream or yogurt or cheese, be prepared to welcome some unwanted pests!
- Diseased plants and leaves – Adding these to your compost is a really good way to encourage diseases to propagate in whatever is unlucky enough to try growing in your composted soil! Either burn diseased plants and leaves or jam them into a garbage bag for trash pick-up.
- Grain products – breads, cakes and other baked goods, pasta. Four-legged critters love this stuff!
- Hygiene items – Anything that could have human or animal fluids on them should never get close to a compost pile! ‘Nuff said.
- Manure – Many people use droppings from cows, horses, pigs, chickens, etc., but, I don’t care whose manure it is…human…animal. It’s too much of a health risk. Don’t even add used kitty litter!
- Meat – All meat, bones, blood, fats from any type of animal or fish will introduce the bad anaerobic bacteria, create a big stink, and attract unwanted critters to a compost pile.
- Non-biodegradable items – This includes anything plastic or plastic-coated, Styrofoam, Tyvek, any cardboard that had contained a greasy item.
- Nuts – Some nuts contain elements that are poisonous to plants. Don’t take a chance. Keep them away!
- Rice – Will attract rats, mice, and introduce the wrong type of bacteria.
- Sawdust – If you know that it came from untreated wood, it is fine to throw some into the pile but, otherwise, don’t take a chance. Don’t use plywood or pressure-treated wood.
- Weeds – Weeds, especially perennials, love growing in a compost pile. They will probably hang out until they can take over the garden once covered with compost that is polluted with them. And, don’t get me started on kudzu…there’s no stopping it!
Get Started Building A Pile!
Find a well-drained area…with some sunshine…preferably, close to the garden…but, as far from the house as possible. Personally, I prefer not to be awakened in the middle of the night by a putrid odor caused by a compost pile that is in need of a bit of dry, brown stuff to balance it out.
But, keep the compost pile close enough to get a garden hose to it if water is needed.
- Start the composting area with a layer of dry and brown ingredients.
- Add a layer of moist and green ingredients.
- Keep the layers several inches thick.
- Alternate layers until you have a pile about three feet high.
- Throw in a little dirt from the garden…or some mature compost…here and there to help introduce some aerobic bacteria and worms. This can speed-up the process by bringing in some “veteran composters.” Otherwise, you may have to wait a little longer for the newbie bacteria and worm crew to get there and start the decaying process.
- Use a shovel or garden fork to turn the pile every couple of weeks to get some oxygen down through it.
- Keep it moist but not soggy.
And, that about it! It’s pretty straightforward.
Do I Have The Right Mix Of Ingredients?
The Right C:N Ratio
The best compost has about a 30:1, carbon (C) to nitrogen (N) ratio. This helps the aerobic bacteria process organic matter into compost.
If the ratio increases…for example, 40:1, 50:1, or even 60:1…decomposition slows down and could even stop altogether…which means you have added too much carbon (dry, brown ingredients). Thus, it is time to add some moist and green stuff to bring the ratio back down.
If the ratio decreases to the point that the compost pile starts to smell rotten and nasty, then, there is too much nitrogen (moist, green material) and, it is time to add some dry and brown bits and pieces to elevate the ratio.
Some Typical Ratios
| Moist and Green | Dry and Brown |
| Humus (soil) – 10:1 | Corn stalks – 60:1 |
| Food waste – 17:1 | Leaves – 70:1 |
| Seaweed – 19:1 | Pine needles – 80:1 |
| Veggie scraps – 25:1 | Straw/hay – 90:1 |
| Coffee – 25:1 | Shredded newspaper – 175:1 |
| Garden plants – 30:1 | Sawdust – 500:1 |
| Fruit waste – 30:1 | Wood chips – 700:1 |
Example – If you take one part food waste (17:1) and add it to one part corn stalks (60:1), you get a ratio of about 38:1 which is very close to the optimal C:N ratio (60 + 17 = 77, 77 / 2 = 38.5).
Let It Breathe
Aerate by turning the compost with a shovel or garden fork to mix it. Another option is to raise the compost bin off the ground and sit it on a pallet. Either way, aerating will allow the pile to be immersed with oxygen and facilitate decay.
These two gardening implements by Fiskars are just the ticket as companions to a compost pile!
If the compost is not turned occasionally to mix oxygen through it, chances are the pile will just sit there…it won’t break down…and, it will start to emanate a putrid stench!
Give The Pile A Drink
60% moisture content is the best. If the moisture level gets above 70%, anaerobic conditions are created and nasty odors will ensue. If moisture gets below 50%, decomposition slows down.
Some Normal Moisture Content Percentages
- Organic food waste – 80% to 90%
- Fresh cut green yard waste – 70%
- Sawdust – 25%
You could get all scientific and “exactly” measure moisture content by weighing a moist portion taken directly from the compost pile, drying it out and weighing it again…then divide the difference by the dry weight.
Example – The moist portion weighs 5 pounds. The dry portion weighs 3 pounds. The difference is 2 pounds. Dividing the difference by the dry portion (2 lbs / 3 lbs) equals a moisture content of 67%.
My neighbor, Jed, a retired farmer, taught me a much simpler way…
He said, “Jimmy…grab a handful of that there compost and squeeze it. If it falls through your fingers, it is too dry so, add some water or green stuff. If it clumps up…and your hand is a little wet…then you got the right amount of moisture in that pile. But, if the clump drips water when you squeeze it, you’re gonna have to either fork it a bit or add some dry, brown stuff…or both…to get it right.”
My takeaway from Jed’s advice is…if the compost has about the same moisture content as a wrung-out sponge, it is right-on-the-money.
Now, doesn’t that sound like a trouble-free way to check for moisture?
What about pH?
Top-notch compost has a pH between 6.0 and 7.8. It’s simple to check it with a pH tester like the Dr.meter S30 3-in-1 Soil Moisture Meter Indoor Outdoor or the Rapitest 1818 Mini 4-in-1. Reviews for these two testers are found on the Sensors and Probes page.
Temperature Is Also Important!
Cooler temperatures slow down the composting process. On the other hand, warmer temperatures speed up the process.
For composting success, the pile temperature should stay somewhere between 130 and 160 degrees Fahrenheit. The aerobic bacteria will be most active and these temperatures will kill most of the weed seeds and pathogens in the compost.
There is actually a special thermometer for use with compost. It is 20” long and will tell you if your compost pile is decomposing actively. It is the REOTEMP FG20P Backyard Compost Thermometer – 20″ Stem, with Composting Instructions (Fahrenheit). There is a review for it at the bottom of the Compost Bins review page.
Stick a thermometer in it once in a while to check it. If it’s too hot, add some water or some moist and green stuff. Too cool? Add some dry, brown stuff!
Now, When Is It Cooked Enough?
When the compost is mature, it will look like humus, the dark, organic component of soil. It will also smell and feel like soil. The compost will no longer emit heat, the carbon to nitrogen ratio will be less than 30:1, moisture content will be well below 60%, and the pH will be close to neutral (7.0).
Decisions…Decisions…
- Can I just make a big pile and keep adding to it…letting it expand naturally?
- Do I use my carpentry skills and make a bin for my compost?
- Or, maybe, I should just bite the bullet and buy a composter that can do most of the work for me since they are normally designed to be easily rotated to mix oxygen through them?
Personally, I choose the latter and I have compiled some reviews for compost bins and tumblers that you may be interested in reading.
And, In Closing…
Compost is best aged a little…like a fine wine. I enjoy drinking a good ’97…but, I don’t want something that was made last week and neither does my garden!
What’s your position on all of this? I appreciate your comments below or an email: jim@perfect-vegetable-garden.com.
Thank you for this enlightening post on composting for a healthy garden! I have always been curious as to what moisture content, pH, and C:N ratios are perfect for a healthy compost. The breakdown of materials that can be added to the compost to control these parameters is also incredibly helpful! I’ll be checking out these composting bins very soon 🙂 Thank you for the inspiration to get back into composting!
Hi Ciara!
I’m glad you enjoyed my composting article. Every gardener worth his salt should be composting. It saves money on fertilizer and it is the most natural way to give plants the nutrients they need for a healthy life.
Someone asked me if the carbon to nitrogen ratio is a new concept. I told them, “Yes!” As far as I am concerned, the knowledge has only been around for about 3 or 4 decades…because, my father drilled it into me every year when I was a youngster helping him in our family garden. 😉
Jim
Hi Jim.
Excellent breakdown (no pun intended) of the composting process.
I thought I knew enough but you enlightened me in a couple of areas.
Another thing I avoid adding to compost is anything from the onion family. Onions, shallots, etc even garlic.
I read somewhere once they can inhibit the process and if not completely decomposed when added to the garden can be toxic to our good friends, the earthworms.
Excellent and informative website, thanks for your good work.
Thomas.
Hi Thomas,
Onions scraps will not affect the microbes in a composting pile and are an important composting ingredient – unless you have a “vermicomposting” setup.
Vermicomposting means “composting with worms.” And, worms, quite frankly, can be a bit finicky. They don’t like onions, potatoes, or garlic. Onions, being highly acidic, will mess with the worms’ gastric systems.
Believe it or not, worms don’t even like broccoli!
Jim