Composting: How waste can be your biggest asset

     by Hillary Burgess,  former Living Collection Manager

Gardens exemplify the natural order of life: birth, growth, reproduction, death and then decomposition which completes and fuels the cycle again. Unfortunately, a lot of yard waste gets hauled away as trash and winds up in landfills, thereby cutting out the final link that keeps the cycle alive and sustainable. A better option is to utilize a little knowledge about the science and technique of composting. You can easily harness earth’s natural processes for the benefit of the soil and plants in your garden. By recycling your yard waste into compost and mulch you also save space in landfills, where lack of the right environment causes decomposition to go surprisingly slowly.

These kitchen scraps will decompose into rich nutrients that can be used in the garden.

So how does composting work? Many bacteria, fungi and other organisms that exist naturally in the soil and around us are sustained by performing the processes that break down dead organic material. By putting together yard and certain kitchen waste in the right environment, decomposers will go to work and the end result is soil that is full of nutrients that are essential to plant health.

This natural fertilizer can often be used in place of synthetic fertilizers. In fact, synthetic fertilizers can alter the amount and even kill decomposers in your soil, taking the natural system of nutrient cycling out of balance—potentially making your plants dependent on synthetic fertilizers for their source of nutrition. By putting the right plant in the right place, and promoting a healthy soil food web, you can reduce or eliminate the need for bought fertilizer.

 
The ingredients for success are heat, water, air, and organic material. Each of these factors is interdependent and influences one another. The place to start is with organic material, yard waste such as grass clippings, leaves, wood chips, straw, sawdust, branches as well as kitchen scraps excluding meats and fats are perfect. For any of these items, the smaller the size, the faster they will break down. It is ideal to shred large leaves and to chip wood.

Then the need for the right quantities comes into play. Decomposing organisms, as a whole, require mostly carbon, and a bit of nitrogen to get the job done. One easy way to keep track is to know that brown, dry materials contain much more carbon than green, fresher items such as kitchen scraps, which are richer in nitrogen. Three parts “brown” to 1 part “green” is a good starting point. This should support the needed variety of organisms, and keep the process moving along efficiently without a funky smell.

As for the other environmental factors, it is important to keep the compost moist, not sopping, but never dry. Heat comes when all of the other factors fall into place, and is a byproduct of decomposition. You will be able to feel heat coming off, and should continue to feel it until the material is mature. Finished compost will be dark and you will no longer be able to recognize most of the original components. If you find that your compost is not giving off heat, but has not yet matured, try turning it first, and then add more Nitrogen (green) material if needed.

Lastly, air or aeration is essential for temperature regulation and so that decomposers can breath. This can be achieved by turning your compost with a pitchfork or another tool, and by working within a ventilated or open space. Turning your compost is important also for distributing decomposers and ensuring that the process takes place evenly.

Compost bins come in many shapes and sizes.

Composting can be as simple as applying everything you’ve learned above, and sticking the stuff in a pile, turning it every so often, and monitoring its moisture. There are also many do-it-yourself bin options, from containing your ingredients inside chicken wire, to constructing a bin out of used pallets. Plans for these options and many variations are available online. You can also purchase rotating or stacking containers that keep the composting process contained and convenient. They also often provide modes of capturing compost tea--liquid that comes off your compost and can also be used as fertilizer. The University of Florida offers a great overview of options.

These guidelines are intended for efficient and stink-free compost. If you are willing to wait awhile or put up with some smell, you can really just pile up any organic material in a forgotten corner of your yard and let mother nature do her thing. Fortunately the climate in South Florida is conducive to decomposition, so even a neglected pile will take much less time than in colder, drier places.

Now you know enough to get started composting. After experimenting over time you will find what works best for you. Excellent resources that cover all of the possibilities and science in great depth include The Rodale Book of Composting and Teaming with Microbes: A Gardener’s Guide to the Soil Food Web. If you like the idea of using compost but are unable to make it yourself, free compost and mulch are available from the City of Miami to its residents at their Virginia Key location at 851 Rickenbacker Causeway.

Once you have finished compost, you can use it in a variety of ways. If you have soil (which can be hard to find down here) you can mix in your compost, the deeper the better. Another option is to add it as a 1-3 inch top dressing to your plantings. For potted plants or planting beds, equal parts compost to soil will be ideal. No matter what, compost will provide nutrients that your plants will appreciate, with the added benefit of holding moisture.