Composting

Posted under Landscaping, Lawn Care, Maintenance, Suggestions for Other Work, Weeds

Composting is controlling the natural decay of organic matter by providing the right conditions for composting critters to convert yard trimmings into a product that can be returned to your landscape and garden. Tiny organisms (mainly bacteria, fungi and protozoa) break down garden and landscape trimmings in a moist, aerobic (oxygen-demanding) environment. The final product is a dark, crumbly form of decomposed organic matter.

Compost improves your soil. When added to soil, compost breaks up heavy clay soils, helps sandy soils retain water and nutrients, and releases essential nutrients. Compost also contains beneficial microscopic organisms that build up the soil and make nutrients available to plants. Improving your soil is the first step towards growing healthy plants. More information is available by requesting Recycling Yard Trimmings: Home Composting, IL 48.

WHAT CAN I COMPOST?

Most plant material can be used for compost. Organic trimmings in your landscape, such as fallen leaves, pine needles, grass clippings, flowers and the remains of garden plants make excellent compost. Compost made from grass clippings treated with herbicides and pesticides is not recommended for use in vegetable gardens. Kitchen scraps, such as fruit and vegetable peels and trimmings, crushed eggshells, tea bags, and coffee grounds and filters can also be composted. Woody yard trimmings can be run through a shredder before adding to the compost pile. Sawdust may be added in moderate amounts if additional nitrogen is applied. Add a pound of actual nitrogen per 100 pounds of dry sawdust.

WHAT MATERIALS SHOULD AVOID ADDING TO MY COMPOST PILE?

Organic materials that should not be added to your compost pile include meat, bones and fatty foods (such as cheese, salad dressing and leftover cooking oil). Do not add pet or human wastes to a compost pile.

Weeds that have not gone to seed can be added to the compost pile. Weeds with large storage roots like nutsedge, Florida betony or greenbriar should be left out and dried in the sun before composting to reduce their chances of survival.

The high levels of heat produced in the center of the compost pile can kill many pests, such as weeds with seeds and diseased or insect-infested plants. However, it is very difficult to mix the contents thoroughly enough to bring all the wastes to the center, so some disease organisms may be returned to the garden with the compost.

“ESSENTIALS” OF COMPOSTING

Organic materials for composting all contain nutrients that provide energy and growth for microorganisms. These organic materials each have their own ratio of carbon to nitrogen (C:N) in their tissues (Table 1). These C:N ratios are important because the tiny decomposers need about 1 part of nitrogen for every 30 parts of carbon in the organic material. If the ratio is greater than 30:1, nitrogen will be lacking and materials will decompose more slowly.

Leaves, straw and sawdust are high in carbon, while grass clippings, manure and vegetable scraps are higher in nitrogen. It helps to think of these materials as greens and browns. Greens, such as grass clippings, are high in nitrogen. Browns, such as leaves or sawdust, contain high amounts of carbon.

Be aware that anything organic will decay (as long as it is organic, the critters will eat it); however, it may take a long time to make compost when the C:N ratio is too high. For example, a pile made solely of sawdust will take years to decay. Adding more greens, such as grass clippings or vegetable scraps, will speed up decay and produce compost in less time. Experiment to find the right combination of materials for your compost pile.

Table 1. Average carbon to nitrogen ratios for organic materials.

Greens: Pig manure 5-7:1 Coffee grounds 20:1 Vegetable scraps 12-20:1 Grass clippings 12-25:1 Cow manure 20:1 Poultry manure (fresh) 10:1 Horse manure 25:1 Alfalfa / sweet clover hay 12:1 Poultry manure w/litter 13-18:1 Horse manure w/ litter 30-60:1

Browns: Leaves 30-80:1 Cornstalks 60:1 Straw 40-100:1 Bark 100-130:1 Paper 150-200:1 Sawdust 400:1 Wood chips 800:1

Surface Area and Size of the Compost Pile: The more surface area the microorganisms have to work on, the faster the materials will decompose. You can increase the surface area of your yard trimmings by chopping them up with a shovel or running them through a shredding machine or lawnmower.

A large compost pile will insulate itself and hold in the heat created by the tiny organisms. Piles smaller than 3 feet x 3 feet x 3 feet have trouble holding this heat, while piles larger than 5 feet x 5 feet x 5 feet prevent enough air from reaching the center of the pile and the microbes. In addition, turning a large pile is a chore. If your pile is large, you will have to turn it more often. If the pile is small, you will get a good batch of compost during warm months.

Moisture and Aeration: The microbes in your compost pile need a certain amount of water and air to survive. Microbes function best when the materials are about as moist as a wrung-out sponge and are provided with plenty of air. Too much moisture will force out the air and suffocate the microorganisms. Too little moisture will slow down decay. Whenever you add water, be sure to mix the material to distribute the moisture evenly.

Turning the materials in your pile supplies oxygen to the composting critters. A lack of oxygen in a compost pile can lead to an odor problem due to the production of ammonia and methane gases. Decomposition without oxygen also causes the production of chemical compounds that are toxic to plants. Organic matter that has been allowed to decompose without oxygen (for example, “composting” in closed garbage bags) should be exposed to air for several days to complete the composting process and to destroy any plant-toxic compounds.

Temperature and Time: As a result of the decomposition process, the interior temperature of the pile should peak between 90 and 140 °F or higher. A hotbed (or long-stemmed) thermometer can be used to check the interior temperature of the pile at least 12 inches from the surface. The intensity of the process depends on the amount of nitrogen in the materials. The time required to produce compost depends on the kind and coarseness of the materials, volume of the pile, and availability of moisture and air. It can take a month, a year or longer.

SOME COMPOSTING METHODS

“Fast” Compost Recipe: This method can produce compost in a couple of months or less but is labor-intensive and requires frequent turning. Start your pile with a layer of browns, and then add a layer of greens. If the greens are not fresh, sprinkle in some blood meal or cottonseed meal, poultry manure, or other nitrogen source. Mix well and add water if necessary to moisten. Adding a layer of garden soil, old compost or manure to each brown-green layer will introduce more critters to speed up the process.

Continue adding and mixing layers of greens and browns until you either fill the bin or run out of materials. Slant the top of the pile to the center to catch rainfall. You may want to cover the pile with a plastic covering or tarp to regulate the amount of moisture entering your pile. The cover should not rest on the pile because it may cut off oxygen.

Periodically, check the moisture content of your pile. The compost should feel damp. Check the interior temperature of your pile and when the temperature reaches 140 °F or begins to fall, it is time to turn the pile. You will need to turn your pile every three to five days. Once your turning causes no rise in temperature, and the material appears dark and crumbly, your compost is ready.

“Slow” Compost Recipe: Slow composting is the least labor-and time-consuming way to compost; it is ideal for people who do not have a large amount of yard trimmings to compost all at once. This method can take from six months to two years or longer to produce compost, so be patient.

The ingredients are the same as those for a “fast” compost. Add greens and browns to your pile whenever they become available. Turn the pile occasionally to mix the materials together to prevent the materials from clumping together and to avoid anaerobic decomposition. You will know that your materials are decaying without oxygen by the foul odor: a telltale sign for you to turn the pile. Look for ready-to-use compost near the bottom of the pile.

COMPOST STRUCTURES

Composting structures can be made from a wide variety of materials or purchased through local garden centers or mail order catalogues. There are no set rules when building a compost bin. The sides should be loose enough to provide some air movement and one side should open for easy

turning and compost removal. If you choose not to use a container, cover the heap with a layer of yard trimmings or soil to prevent moisture loss.

Circular Bins: A circular bin is very useful for composting larger quantities of organic materials, and can be easily made from a length of closely spaced woven wire fencing held together with chain snaps. The bin should be 3 to 5 feet in diameter and at least 4 feet high. It is easiest to turn the composting material by simply unsnapping the wire, moving the cylinder a few feet, and turning the compost back into it.

Simple bins can be made of old wooden pallets stood on their ends in a square or open square and nailed or tied together. A chicken wire cage supported by three or four wooden stakes will also work well. A standard-sized garbage can with eight or more slots in the sides of the can for ventilation and five in the bottom for drainage can also be used.

Three-Chambered Unit: A three-chambered bin works on the assembly line principle, and is an efficient structure for “fast” composting. Three batches of compost are in various stages of decomposition at all times. The composting process is started in the first bin for three to five days. This material is then turned into the middle bin for another four to seven days and a new batch is started in the first bin. Next, the middle bin is turned into the third bin as nearly finished compost. Each bin should be at least three to five feet in each dimension and should be made with rot-resistant wood (redwood) or wood treated with an environmentally safe preservative.

Barrel or Drum: The barrel or drum composter is an excellent choice if you have limited space in your yard. A barrel of at least 55-gallon capacity with a secure lid is required. To provide good air circulation and drainage, drill six to nine rows of half-inch holes over the length of the barrel, and place the barrel upright on blocks. Fill the barrel three-quarters full with organic wastes and add water to lightly moisten. Mix the compost every few days by turning the drum on its side and rolling it around the yard. The compost should be ready in two to four months.

USING COMPOST

Think of compost as a soil amendment and not as a fertilizer, since the nutrient level of compost is low and released over time. Mix compost with soil to enrich the flower and vegetable garden. It can be used to improve the soil around trees and shrubs, as a top-dressing for lawns, or as a mulch. Screen compost by separating the larger particles and any uncomposted materials from the finer ones and add it to the potting mix for houseplants. No more than one-quarter to one-third by volume of the potting mix should be compost. Soaking compost in a burlap or cheesecloth sack steeped in water can make compost “tea.” The weak nutrient solution can be given to young plants.

Table 2. Troubleshooting guide for efficient composting.

Symptoms	Problems	Solutions
Rotten odor	Not enough air; pile too wet	Turn pile; add coarse, dry materials (straw, corn stalks, etc.)
Ammonia odor	Too many greens (excessive nitrogen/lack of carbon)	Add browns (straw, paper or sawdust)
Low pile temperature	Too small; not enough air or moisture; few greens; or cold weather	Make pile larger; add water while turning the pile; mix in nitrogen sources (grass clippings, manure, or a synthetic fertilizer, such as 10-10-10); or insulate the pile with a layer of straw or plastic
High pile temperature	Too large; not enough air	Reduce pile size; turn pile
Pests, such as rats, raccoons or insects	Meat or fatty food scraps in pile	Remove meat and fatty foods from pile; cover with a layer of soil or sawdust; build an animal-proof compost bin.

Landscape Irrigation Management Part 1: Water in the Landscape

Posted under Irrigation, Landscape, Maintenance, Suggestions for Other Work

Many in the Southeast view irrigation as a “quick fix” for problems encountered during a hot, dry summer. It is a simple way to get some water to plants that are wilting and keep them alive until rainfall returns. Others see irrigation as a method to provide all of the water a plant may need on a daily basis. Neither of these views will provide a good habitat for our landscape plants.

Irrigation is quite simply a balancing act. We are attempting to maintain a given soil moisture content for optimum plant growth.

When too much water is applied to the landscape, the excess water saturates the root zone and replaces oxygen in the rooting area. Plant roots require oxygen to grow properly, so the anaerobic (without oxygen) conditions in a saturated or flooded landscape do not provide the ideal growing medium for a plant. Plants that are found in a flooded or saturated area are often referred to as “drowned,” which is an apt expression.

When too little water is applied to the landscape, plants begin to dry and wither. Every plant transpires (or emits) an amount of water through the stomata (small openings that vary in size with the climate conditions) in the leaves as a part of the plant’s water use and transport / production processes. When a plant finds itself in a drought condition, it usually begins to hoard its water supply by partially closing the stomata. This restricts water flow through the plant and results in slower transport processes as well as wilting. If we allow the plant to be “drought-stressed” in this manner for too long, the plant will be weakened and may even die.

Irrigation is one method to replace water in the soil used by the plants. As previously mentioned, this is a balancing act. We must apply enough water to maintain a plant’s growth, but not so much that we saturate the soil and drown the plant. We must also consider other water additions to and subtractions from the landscape.

Figure 1. The irrigation balancing act.

Water Additions to the Landscape

Rainfall: Rainfall is an obvious contributor of water to the landscape. Nice, gentle showers provide a great deal of water over a period of time, most of which may stay in the landscape. Intense thunderstorms, however, often provide water more quickly than the soil can absorb it. In this case, excess water will actually “run off ” (explained later in the text) and leave the landscape, so we may not receive the full benefit of all the water that fell in our rain gauge.

Snow, Sleet & Hail: Each of these forms of precipitation also contributes water to the landscape, albeit during times of the year when our plants may not require very much. “Wet” snow that falls when the temperature is near freezing may contribute up to 1 inch of water for every 6 inches of snowfall, while “dry ” snow that falls during much colder weather may contribute up to 1 inch of water for every 12 inches of snowfall. Sleet and hail will also contribute water (although hail will hopefully not fall in a large enough quantity to provide an appreciable amount of water).

Irrigation: This is the man-made method of applying water to the landscape. Some concerns that apply to rainfall also apply to irrigation – if water is applied too quickly, some of it may “run off” and provide no benefit to the landscape.

“Run-On”: Assume that your neighbor’s yard is a few feet higher in elevation than your yard. If a hard rainfall event occurs, some of the water may “run off” from that yard and subsequently “run on” to your yard. If the water stays in your yard it will contribute to the soil moisture in your landscape. This “run-on” may be beneficial in a dry year, but it may also be a continual problem in a wet year if it saturates your landscape soil regularly or creates a wet spot. If this is the case some form of drainage (drain tile, etc.) or runoff water diversion (terrace, etc.) may be necessary.

Water Subtractions from the Landscape

Evaporation: Everyone is familiar with the evaporation of water from puddles, water glasses, ponds and swimming pools. Soil moisture may also be lost from a bare soil surface due to evaporation. Only the top inch or so of soil may be subject to this evaporation, but in a drought situation, every drop counts. Mulches help reduce this soil evaporation loss.

Transpiration: This is a large word for “plant water use.” The water taken up by a plant is largely “transpired” as water vapor through the stomata in the leaves, then “ evaporated” into the atmosphere. (The term “evapotranspiration,” also called “ET” in irrigation publications, refers to plant transpiration plus soil evaporation.)

Runoff: Soil can accept water at a certain speed or rate, called the infiltration rate. This rate of water movement into the soil varies with soil type (and other factors). When water is applied to the landscape faster than the soil can accept it, the excess water “runs off” across the landscape, giving us the term “runoff. ”

Water that “runs off” has quite obviously left your landscape and will not be there when plants need it. If runoff occurs during a thunderstorm, we assume some portion of the rainfall received will benefit our landscape but not the full amount found in our rain gauge. Quickly-moving runoff water can also cause soil erosion, creating rills (small eroded channels) and small gullies in the landscape.

The same principle applies to irrigation – any water that runs off is leaving your landscape and not providing moisture for plants. If you see water running off during irrigation, stop the irrigation system, allow the water to soak in for an hour or so, and then resume irrigating. If the runoff is due to a steep slope or heavy soils (clays, etc.) you may need to change your irrigation schedule to water for a shorter amount of time twice that day rather than a single long irrigation set. This will help conserve water and make sure your landscape will receive all of the water purchased or pumped.

Driveways and sidewalks can also contribute to runoff losses if sprinklers are not adjusted correctly. Any water applied to a concrete or asphalt surface will immediately run off to the nearest ditch or culvert. Water applied to these areas can also create liability problems for the homeowner, especially if an irrigation system turns on unexpectedly while pedestrians are using the sidewalk. Make sure all sprinklers and spray heads are adjusted correctly so that the water is applied to the landscape, not the pavement.

Leaching: Assume that your yard is completely level, the soil is somewhat coarse or sandy, and no runoff occurs during irrigation. If you apply more water than the soil can hold , the extra water has to go somewhere. In this case it moves downward through the soil profile. When the extra water moves past the root zone of the landscape plants, it has in effect “leached” out of the root zone. The water is still in the soil, but it is too deep for the plants to retrieve it. This water has left your landscape just as effectively as if it had run off over the top of the ground.

Excess water leaching past the root zone has another detrimental aspect. The leaching water may move water-soluble compounds in the soil (such as fertilizers and pesticides) down with it. This removes these compounds from the root zone area where they are needed and may eventually transport them to the groundwater. A homeowner will lose fertilizer, pesticide or herbicide, and water if leaching occurs and may also impact the groundwater in that area.

Summary

In order to provide the best growing environment for our landscape plants, we need to first understand where the water comes from - and how the water may leave our landscape. This simple knowledge provides a basis to help us understand the reasons for various irrigation practices used today.