Why Use Compost? If you use compost, you can save time and money. Compost improves low quality soils by adding organic matter and nutrients. Plants grown in good soil are healthier and have greater resistance to diseases and insects. By greatly reducing the need for pesticides and fertilizers you save money. Plants grow healthier and using fewer synthetic pesticides and fertilizers also reduces your risk of contaminating drinking wells, local streams, ponds, and lakes. Compost use can: 1. 2. 3. 4. 5. 6. prevent erosion. improve moisture retention. reduce the need for fertilizers. suppress soil-borne plant diseases. be less expensive than topsoil. divert a valuable resource from the waste stream. How to Use Compost at Home Compost has many valuable applications around the house. Brief descriptions of each application are in this brochure. 1. 2. 3. 4. 5. 6. 7. 8. 9. On the Lawn For Potted Plants Tree and Shrub Planting In the Garden As Mulch Improving Soil Quality Starter Mixes Make Compost Tea Plant Disease Suppression Compost Quality The compost you use should be of good quality whether it was purchased or produced yourself. Good quality compost is mature. It will not reheat if you add water to it or turn it. It should be a dark color, of humus-like quality, and have a pleasant soil smell. If you produce your own compost, you can make sure it is of good quality by controlling what you put in it, using the right mix of greens and browns, and keeping the moisture level at that of a damp sponge. Meat, dairy and greasy foods should be avoided. Also, avoid items such as diseased plants and pet feces. High temperatures are needed to kill pathogens and weed seeds. When purchasing compost, it is best to buy from companies with known feedstocks (ingredients). There are currently no requirements for labeling compost and few regulations regarding compost quality. Good compost companies will provide the buyer with typical analyses of finished compost. Of particular importance in compost are the pH and the salt content. If the pH level or salt content is high, it can stunt plant growth. Do not use compost made from municipal sludge or biosolids for food gardens unless it has consistently tested free of heavy metals and pathogens. When used on nonfood items, application rates should not exceed 4 cubic yards per 1,000 square feet unless another rate has been determined safe by the testing. This limit has been established to minimize environmental risks. 1. On the Lawn 3. Tree and Shrub Planting To establish a new lawn, put 4 to 6 inches of compost on the soil and till it to a depth of 5 to 8 inches. For an existing lawn, apply a thin layer (1/8 - 1/4 inch) of fine compost on the lawn and water it well. This can be done at any time of the year. It will improve nutrient levels and reduce watering needs. To fill in bald spots create a mixture that is 30% compost, 60% topsoil and 10% grass seed. Then spread a 2 - 4 inch layer over the bald spot and water thoroughly. Nutrient run-off is a big problem in many watersheds. Too many nutrients cause overgrowth of plants in rivers and lakes. Though farming can have a significant effect, studies have shown that homeowners add large amounts when they use synthetic fertilizers. Healthy soils from compost use can reduce or eliminate the need for additional fertilizers. Mix compost with soil from the hole for planting the tree. The mixture should be about 1/3 compost and 2/3 native soil. Use this to fill in the bottom of the hole around the root ball, then water. 2. For Potted Plants Potting soil can be made with 1/4 to 1/3 finished compost and the rest sterile soil or sand. You can also sprinkle a thin layer of compost over house plant soil to add nutrients. This is also excellent to correct drainage problems in soils that have cracked or pulled away from the container. Do not put plants in pure compost. Plants need coarser particles such as sand and soil in order to root properly. 4. In the Garden Add compost to your garden each year in spring or early summer before planting. Till the soil to a depth of 5 to 10 inches. Apply 4 inches of compost on top of the soil then till it again to mix it. If the soil is very poor, you can add more. Don’t worry about adding too much compost. Compost releases nutrients slowly and continuously and will not damage plants. Throughout the growing season you can add a sprinkle of compost mixed with soil as a top dressing. You can also apply a couple inches of unfinished compost in the fall to be tilled in the spring. 5. As Mulch In early summer put a 2 to 6 inch layer of coarse compost on soil around trees and plants for a mulch. This will help conserve water, protect against soil erosion, and weeds. Compost made from woody materials works best. The mulch should not be spread directly against the tree trunk. Apply a 2 inch layer about 6 inches from the trunk and out past the drip line. 6. Improving Soil Quality 8. Make Compost Tea Adding compost to clay soils will lighten the soil allowing more water and air to circulate through it. This is important for root growth. Compost can also be added to sandy soils to increase the water holding capacity and provide essential nutrients. Spread a 4 inch layer of compost and till it 5 to 8 inches into the soil. Doing this for several years will produce a rich, humic soil Compost tea is very beneficial for plants. It provides them with all the nutrients and microorganisms of compost that can suppress soil diseases. To make compost tea you will need a large bucket, a cloth sack and some rope. Put some compost into the sack and tie the opening shut with rope. Place the sack into a bucket of water and let it steep for a few hours or days until the water is the color of a light tea. Use it to water house plants or your garden. However, compost tea does not have a long shelf life. Do not try to store it for long periods, or it will become anaerobic and less beneficial for your plants. Compost tea is also known to cause disease suppression when sprayed on plants. 7. Starter Mixes High quality, mature compost can be used in starter mixes because it is sterilized during the composting process at high temperatures. Create your own mix using compost, either purchased or from your home composter. An easy recipe is, 1 part mature sifted compost 2 parts soil 1 part sand, perlite or vermiculite Make sure the ingredients are well mixed. If there is a question about pathogens or insects in the soil or compost, the mixture can be sterilized by moistening it and heating it in the oven at 200 degrees for one hour or in the microwave for 10 - 15 minutes (to 180 degrees.) This may produce an objectionable odor. If the compost is known to be a good quality, add it after sterilization so it retains the good microbes. Resources: Check with your local solid waste district or committee for local resources and composting classes. The UVM /Extension Master Gardener Program: http://pss.uvm.edu/mg/mg/ The Master Gardener Helpline: 1-800-639-2230 Summer hours: Monday-Thursday 9am-noon & 1pm-4; Friday 9 am-noon. Compost Uses Every Homeowner Should Know The Rodale Book of Composting, The Rodale Press, Emmaus, Pennsylvania, Chapter 12. © 1992 Backyard Composting, Harmonious Press, Sebastopol, California, Chapter 6. © 1992 Prepared by the: 9. Reduce Pesticide Use A benefit of using compost is plant disease suppression. In order to have disease preventing properties, compost must be stable and well decomposed but not overly aged. It is believed that in some plants, compost activates disease resistant genes. The microorganisms in compost are antagonists to plant pathogens as well. Soils lacking organic matter have low energy reserves for microorganisms and are susceptible to developing soil-borne diseases. Healthier soil means healthier plants, which reduces the need for pesticides. 103 South Main Street Waterbury, VT 05671-0404 802-241-3448, [email protected] with assistance from The NEBHE New England Environmental Internship Program: http://www.nebhe.org/env.html For more information about composting, compost use, and compost companies in Vermont, go to the ANR web page at www.anr.state.vt.us/compost. Clipart Courtesy of the United States Compost Council and other web and program sources. State of Vermont Agency of Natural Resources Compost Center