Dr. Kevin Korus: Gardens can feast on your leftover garden feast
This holiday season, you may find yourself with an abundance of food scraps as you prepare meals for friends, family and loved ones. Many of these food scraps, if properly composted, can be returned to the garden to add much-needed organic matter and nutrients. Composting is a natural means of breaking down organic matter into a black, humus-like, nutrient-rich soil. Composting helps reduce waste and can save you money on fertilizer costs. Florida soils are typically very sandy and lack organic matter. Water and nutrient retention are dramatically increased in sandy soils via the addition of compost.
There are several factors that improve compost efficiency. The first is to make sure your compost consists of the correct ratio of “browns” to “greens.” Browns are carbon-rich materials like dead leaves, twigs, clipped branches, shredded paper, cardboard or paper plates, cups, etc. Greens are nitrogen-rich materials like kitchen scraps (vegetables, eggshells, fruits, tea bags, coffee grounds), farm-animal manure, grass clippings and other green, fleshy plants. The correct brown/green or carbon/nitrogen ratio for ideal composting is around 30/1. In general, the more broken down these materials are, the faster the composting process will be completed. Composting is a microbe-mediated process, so to inoculate your pile or bin, just add a scoop of soil from the yard or garden.
The effective temperature for complete composting is around 130° F to 140° F. To reach the required temperatures, it is important to make sure that your pile or bin is at least 3 cubic feet. Home compost bins rarely reach this temperature, so it is important to avoid adding weed seeds, or diseased or nematode-infested plants as they may survive the process. Animal products like meat/bones and oils from dressings and fats should all be avoided as well. Not only will they produce a foul odor, but they may attract unwanted wildlife. It should be mentioned that animal manure is a great source of nitrogen for a compost pile but should only be used from ruminant animals (cows, horses, goats, sheep) and not from carnivorous animals like dogs and cats. Dog and cat manure can contain diseases that affect people.
Compost piles or bins should be placed in a shady area within reach of a garden hose and protected from drying winds. Keep in mind that insects are often attracted to compost piles, and this can become unsightly. Piles and bins can be hidden behind privacy fences or some other visual barrier.
Properly assembled piles will heat to an effective temperature and then cool down after about four to seven days. They need to be turned at this time to introduce outside material into the middle. Compost will be ready in approximately six weeks. Small and/or dry piles will take longer to compost. If you desire to monitor the temperature inside your pile, a long-stemmed compost thermometer that reads to 160° F can be used.
Compost is ready when the material crumbles in your hands and turns a dark brown color. If larger pieces still exist, they can be sifted out and added back to the pile or bin. Add about 1 to 3 inches of compost to the soil surface and then mix it into the soil to a depth of 4 to 6 inches.
For more information on composting, visit edis.ifas.ufl.edu/publication/EP323 and gardeningsolutions.ifas.ufl.edu/care/fertilizer/compost.html.
— Dr. Kevin Korus is the Agriculture and Natural Resources Extension Agent for UF/IFAS Extension Alachua County. Contact him at kkorus@ufl.edu or 955-2402.
This article originally appeared on The Gainesville Sun: Dr. Kevin Korus: Gardens can feast on your leftover garden feast
