The Basics of Composting

As you know, I'm starting a Square Foot Garden.  You can read about my experiences with that here.  Compost is an integral part of this. 

Why Compost?
It's great for the garden, a cheaper and healthier alternative to chemical fertilizers, and it's environmentally responsible (you're recycling organic matter that you might otherwise put in a landfill).  Win-win-win.  You can read more about the benefits of compost here. 

Compost is just decomposed organic matter, and a garden thrives on it.  All you do is add the key ingredients (water, air and organic matter), turn it frequently, watch the mix heat up, and within a few weeks or months you have lovely, free compost to spread across your lawn and garden.  

What Can You Do with Compost?
A shorter list might include what you can't do with compost - but here are some ideas on what to do with it: 

• Put compost on top of your garden soil before the ground freezes in late autumn - it'll work to enrich the soil all winter.  It's not necessary to do it, but if you can work it into the soil at the same time, it'll do even more good.  
• Add it to your garden a month before spring planting.  
• Add it throughout the driest part of summer and as you harvest vegetables.  
• Combine it with potting soil when you start seedlings and when you transplant them into your garden.  
• Spread it across your lawn whenever you might ordinarily add fertilizer (e.g., before grass emerges from hibernation in the spring and during the heat of the summer - make sure you water it in so it gets where it needs to go).
• Put down a layer of compost before any routine mulching around shrubs and trees (for trees, add it out to the drip line).

What Kind of Composter Is Right for You?
There are lots of different kinds of composters.  You can build your own or buy one.  Click here to read more about the different types (I use this one.) 

Where Should You Place Your Composter?
You should position your composter or compost pile conveniently near your garden and near a source of water (e.g., garden hose).  If you're in a warm climate, you might want to put it in the shade so it doesn't dry out.  If you're in a cold climate, you might want to put it in the sunlight to help heat it up.

What Can You Compost?
The best compost mix is one part green stuff (materials that are high in nitrogen) to three parts brown stuff (the "fiber" for your compost - materials that are high in carbon).  You can also add other things in moderation. 

Green Stuff:

• grass clippings
• fruit and vegetables from your kitchen that are "past their prime"
• fruit/veg scraps such as banana peels, onion skins, potato/zucchini/carrot/apple peels, apple cores, tomato stems, cantaloupe or watermelon rinds, orange peels, corn cobs
• plain paper bags
• coffee grounds (no more than 10% of your total mix)
• tea leaves (you can leave the bag on but take the staple out)
• vegetable plant remains
• non-diseased plants that you've pulled out of your garden
• herbivorous animal droppings (i.e., not pet or human excrement)

Brown Stuff:

• autumn leaves
• dead plants
• cardboard & cardboard tubes
• old floral arrangements
• old straw

Other Stuff:

• egg shells (not the yolk or egg white)
• animal and human hair
• paper towels
• paper napkins

Do NOT compost: 

• meat or meat scraps
• large seeds or pits such as avocado pits or mango seeds (don't fret overly about small seeds like you might find in an orange or apple - the heat during the composting process tends to take care of them)
• dairy products
• fish or fish bones
• bread
• plastic
• fats/grease/lard/oils
• pet or human excrement
• synthetic fibers
• pasta
• nuts
• cooked food
• weeds that have gone to seed
• diapers
• diseased or insect-ridden plants
• glossy paper or magazines
• anything treated with chemicals
• cat litter

Tips

• Many people find it most convenient to keep a covered can on their kitchen countertop and add scraps there until it's full, then transfer the scraps to a larger composter outside.
• The processing time is "reset" each time you add new ingredients, so some gardeners find it helpful to have two composters so they continue to have a place to put compost ingredients while they wait for the first batch to process.
• Just as human digestion is aided by proper chewing, you should chop up your compost materials before adding them in order to speed the process.  
• The more frequently you turn the pile, the faster the composting process (up to a point - you probably shouldn't turn your pile more often than every 3 or 4 days so the microorganisms have a chance to work on it).  
• The compost pile should be kept moist, like a wrung-out sponge, so add water as necessary.  The best practice is probably to add water as you add materials - that way you're sure to get everything wet.   
• You know your compost is done when it becomes a uniform, dark brown, crumbly product with a sweet, earthy aroma (it should not smell rotten).

Trouble Shooting

• If your compost pile smells bad it either needs more air (so turn it) or is too wet (add dry materials).
• If your pile won't heat up, it's either too small, needs water or more green matter, or the pieces need to be chopped up.
• If your compost is killing your garden, check the pH.  Just as the human body gets out of whack whenever it gets too acidic or too alkaline, so does your garden if your compost isn't pH neutral.  Maybe it's just a matter of letting it sit for longer.  Most compost goes through a pH cycle where it is acidic early on, then becomes more neutral over time.  This trick can also help you solve the problem of garden soil that is too alkaline - put some compost on it when it's more acidic, then turn the soil.  The combination will yield a more neutral pH.
• If your pile attracts flies, rodents or pets, chances are you've put something in there that does not belong (e.g., meat or meat scraps, fatty/starchy foods, carnivorous animal droppings).

An excellent reference book is Let It Rot by Stu Campbell- I highly recommend it.  The EPA also has a helpful website on composting.


Happy composting!