Home & Garden Pest Management Guide For British Columbia 2019 Edition Chapter 7 Soil Management and Composting Soil Management and Composting Availability of nutrients to plants depends on “Feed the soil not the plant.” The how healthy the soil is - good soil tilth will goal of managing a garden soil lead to better nutrient supply. To maintain should be to ensure that the soil is good soil fertility and tilth, organic matter healthy. and fertilizer nutrients should be added regularly. The pH of the soil, which measures how acid it is, will affect nutrient Healthy, vigorous roots make healthy, uptake as will the salt content of the soil.(see vigorous plants. Many plant health problems “Lime and Soil pH”, below). are the result of poor root growth. A suitable soil for growing healthy roots and plants must be fertile and have a good structure or Organic Matter “tilth” which permits air and water movement around the roots and good root Organic matter is primarily added to soil to penetration and growth. improve its physical structure. Depending on the source and degree of decomposition of Soil texture, or the relative amounts of sand, the organic matter it may also supply silt and clay in the soil, imparts most of the nutrients. Organic matter breaks down in the physical characteristics of the soil. Soil soil to form humus. Organic matter can structure, or the arrangement of the lumps improve air and water movement in a clayey within the soil, provide a visual key to soil soil and makes it easier to work. Organic tilth. A “light” soil with a high percentage of matter also improves the water and nutrient- sand or gravel may allow water and nutrients holding capacity of sandy soils. Organic to drain or “leach” out too quickly for most matter should be applied regularly to plants. A sandy soil will also tend to have vegetable gardens, woody ornamentals, and smaller lumps or be single grained. A flower beds. “heavy” soil with a high percentage of clay will tend to become waterlogged and will Organic matter suitable for gardens comes not allow enough air to get to the roots. Clay from a ranges of sources including yard and soils tend to have harder lumpy tilth. A soil garden waste (leaves or grass clippings), that is compacted or hardened will not allow animal manures, composts, peat moss, roots to penetrate and grow well. A “loamy” seaweed, and wood products (sawdust, soil is generally a soil with a mixture of shavings or bark mulch). Peat moss is useful sand, silt and clay particles which, combined as a soil conditioner, but supplies almost no with organic matter, create a friable or well nutrients. The ability of organic matter to aggregated and crumbly structure. supply nutrients depends on its source, particles size and degree of decomposition. A fertile soil is one which contains all of the If wood products such as sawdust are used, essential nutrients (minerals) needed by the extra nitrogen may have to be applied if dry plants for growth. These nutrients must be fertilizer is used. For every layer of sawdust available in sufficient quantities and in a 5 cm deep, add an extra 65 grams of 46-0-0 form that can be taken up by plant roots. urea fertilizer, 190 grams of 16-20-0 Soil Management and Composting - Home and Garden Pest Management Guide 7-1 (ammonium-phosphate-sulfate) per 9 square rather than composting it. Homeowners meters (100 square feet), or equivalent usually add ingredients in small quantities; amount of nitrogen in addition to whatever therefore the compost doesn't usually get amount of nitrogen is needed by the crop. very hot. This is referred to as "cold Applications of liquid fertilizer should not composting". It doesn't kill everything, but be affected by the sawdust and do not need produces good compost. Properly composted to be increased. material should look dark and spongy, and have a fibrous, moist texture. Manures and composts are among the best materials to add because they add organic Compost Preparation matter to soil, often improving aeration, drainage, nutrient-holding capacity, and Compost is produced by the decay of biological activity and other soil properties. vegetative (plant) matter. Compost is a soil However, nutrient levels vary among conditioner, a source of organic matter different composts and most composts do available to all gardeners. Choosing a not supply nutrients in the same ratios that compost site carefully is very important. are needed by plants. If composts are made Partial shade is ideal, to avoid summer from a significant amount of manure, drying and also provide some solar heat to nutrient levels tend to be higher compared to onset composting action. To prevent too other composts such as yard trimmings much moisture loss, choose a site that is compost. Heavy applications of compost protected from drying winds. Locate your may supply high levels of soluble salts, composting site in a spot that is which can be damaging to plant roots. If wheelbarrow accessible to make it easier to composts derived from animal manures are move compost volumes in and out. going to be used in raised beds, containers or planters, the volume of compost should be Compost is made by alternating layers of less than one third of the total volume of “green and brown” material. Examples of ‘soil’ in the container. Weed seeds can be green materials include kitchen waste, grass introduced into the garden by adding clippings, and fruit and vegetables. immature compost or material that has not Examples of brown material include leaves, fully composted, regardless of whether it newsprint, and shredded paper. Do not add contains manure. meat, bones, or dairy products which can attract animals and vermin. Adding a light Composting dusting of soil every few layers will assist the earthworms in breaking down organic Composting is very beneficial to the garden material. Store vegetative matter until and the environment. If plant material is enough is accumulated to make a pile. Chop properly composted at the right temperature, up large, coarse pieces before added them to most insects, diseases and weed seeds may the pile. Materials used in building compost be destroyed. Home composting may not piles should be moist, but not waterlogged. destroy all of these if proper temperature and For example, a large pile of wet grass moisture is not maintained. If weed seeds or clippings will not compost as well as a pile certain pests or diseases are present, it is made of layers of different materials varying advisable to dispose of crop refuse in a in moisture content and texture. Turn or landfill where it will be quickly buried, aerate the compost pile frequently (every Soil Management and Composting - Home and Garden Pest Management Guide 7-2 few weeks or more often) to introduce garden with ripened seeds; and lawn oxygen into the pile. Some plastic compost clippings that have been recently treated bins are not suited to "turning". Compost with weed killer. Avoid highly resinous aerating tools (Wingdiggers) or a sharp wood and leaf prunings from conifer plants stake, can help accomplish this task. A such as junipers, pine, spruce and arborvitae. properly constructed compost pile will not The resins protect these materials from emit offensive odours, but will produce a lot decomposition and extend the time needed of heat. for composting in comparison with other plant materials. This type of plant material If compost is made inside a covered bin or should be buried, taken to a landfill, burned box, heat will be retained. A cover is (where permitted), or placed in plastic recommended in the coastal area to garbage bags and set out with the household encourage heating, prevent loss of moisture garbage for disposal (where permitted). in the summer and reduce leaching by the winter rains. This results in faster Compost piles built in the spring should be decomposition and kills most insect pests. In ready for use in the fall. Those constructed the dry areas of the Interior, a cover is not so in the fall may be ready by spring or early essential and it is more important to add summer of the following year. In regions water periodically during dry weather. The with heavy winter rains, if the compost box box should have holes or gaps in the sides has no permanent cover, use a plastic sheet and bottom to allow air to enter. during the winter to permit faster decomposition and reduce leaching of The ideal is to have three receptacles: one nutrients. Excess water will cause piles to for storage of incoming vegetative materials, become “anaerobic” from lack of oxygen one for the working pile, and one for the and decomposition will stop. finished product. Most homeowners only have space for one compost bin. This is why Composting Pest Problems the plastic covered bins have a door at the bottom, so finished compost can be moved Rats may look at a compost bin as an ideal out, while new material is added to the top. site to nest in. Try to keep compost moist It is also possible to remove the front of a and regularly turned to make a compost pile wooden box and slide the box to a new unattractive. Rats may be looking for food in location before re-attaching the front so that the pile so be sure to bury food scraps. it can be refilled. This eliminates the cost of Consider building an enclosed bin for building three boxes. Screening is not kitchen waste and have an open bin for grass necessary unless a finer product is required clippings and garden waste.