Compost can be very beneficial as a soil amendment or as nutrient-rich mulch.
Last week we detailed how to use yard waste to create a compost pile, which must be managed properly to yield the desired nutrients.
The major management principles are to maintain proper mixture, moisture, heat and size. It can take three to 12 months to produce compost.
To maintain a proper mixture of materials, the pile must be turned once a month, mixing the layers with a pitchfork or moving the pile to another location. Turning the pile ensures all materials are subject to the heat created by decomposing material. This heat is responsible for killing odor-causing bacteria, insect larvae and seeds of weeds. It is important to remember not to add meat products, grease, human or pet waste, charcoal, eggs, dairy or inorganic materials to the compost.
Proper moisture must also be maintained for the decomposing bacteria to thrive. If the pile becomes too saturated, it might smell bad and not produce nutrient-rich compost. Turning the pile more frequently can encourage drying, as can adding more dry materials such as twigs or straw. If the pile is too dry, the decomposition process is limited. Moisture-rich plant materials such as fruit peelings or grass clippings can be added to the pile in addition to watering.
Maintaining proper heat can be difficult without a compost thermometer. The heat inside a compost pile can reach temperatures of 140 degrees and is a by-product of decay that, in turn, speeds the decomposition process.
To maintain the proper heat, new material needs to be mixed with older, decaying material. New nitrogen-rich material such as manure or grass clippings can add additional heat if needed.
The size of the compost pile must support the demand for new material while also being manageable. The ideal compost pile is 3- to 5-feet wide, 3- to 5-feet deep and 3- to 5-feet tall. A small pile might not contain enough plant material to generate the necessary heat and a larger pile is harder to maintain. As the compost pile grows during the maintenance period, it might be necessary to start a new pile.
The composting process is complete when mixing no longer produces heat and the pile has shrunk. The pile will be approximately half its original size and have an earthy smell.
Mulching with compost will increase the moisture-holding capacity of soils and reduce drought damage. Apply a 3- to 6-inch layer of compost around the base of the plant material. Keep the compost off of the base of the plants, because covering this area can promote fungal canker diseases. Throughout the summer, replenish the compost to maintain the 3- to 6-inch layer.
Another use of compost is as potting soil amendment. Leaf compost can be used as a component of potting mixes. Add no more than one-quarter to one-third by volume to the potting mix.
Using compost as a soil amendment improves drainage, reduces compaction, adds aeration and changes the soil’s profile over time. The majority of Columbia County has heavy clay soil that benefits from the addition of compost. Add 1 to 2 inches of compost and till it into the top 6 to 8 inches of soil. For annual gardens, work the compost into the soil at the end of the season.
To a limited extent, compost is a source of nutrients. However, the nutrient content is too low to supply all the nutrients necessary for plant growth. Additional fertilizers will be needed.
It is a good idea to have your soil tested after adding compost to the soil to determine if supplemental nitrogen, phosphorus or potassium are required.
There are now five locations in Columbia County to drop off soil samples in addition to the Extension Office in Appling. They are Brown Feed and Seed, Ewing Supply, Green Thumb West Garden Center, Grovetown Farm and Garden and Southern Landscaping.