Gardens to Groves

Why "Gardens to Groves"?

It is important to remember that what we do at our homes and businesses can affect the water quality and healthy of humans, plants and animals in our creeks, rivers, lakes and oceans.  Commonly used PESTICIDES and FERTILIZERS in gardens and groves can easily find their way into local waterways and adversely affect people, plants and animals.

What are fertilizers and how do they work?

Fertilizers are any of a large number of natural and synthetic materials including manure and nitrogen, phosphorus, and potassium compounds spread on or worked into the soil to increase its capacity to support plant growth.  Fertilizers are used to help plants grow strong and produce the maximum number of leaves, flowers, vegetables or fruit.  Many brands of fertilizer are sold at garden supply stores for home gardeners, while large-scale farmers often use special fertilizers on their crops that promote plant growth and help prevent diseases.

What happens when there is too much fertilizer in our local waterways?

Fertilizers help plants grow.  They don't stop working when they leave your property and enter the local water system.  Fertilizers cause algae to grow incredibly fast and choke creeks and rivers and cover lakes.  When the algae dies, bacteria decompose it and use up all the available oxygen in the water.  This causes fish and other aquatic organisms to die as there is no longer any oxygen in the water for them to breath.  This process of adding fertilizers, algal growth (bloom) and eventual die-off and subsequent fish and aquatic organism deaths is called eutrophication.

The use of chemical fertilizers raises concerns over contamination of groundwater and the surrounding environment.  Rainfall and irrigation runoff can carry the fertilizer residues to the local waterways, causing water pollution.  In addition, the chemical residues may remain and adhere to the vegetables or ornamental plants.  With chemical fertilizers, excess phosphorus is of special concern as it may collect in the soil and cause pollution risks.

How about using organic fertilizers?

Building a soil environment favorable for organism growth while improving aeration and nutrient-holding capabilities are key factors for choosing an organic fertilizer over a conventional chemical one.  While non-organic fertilizers temporarily add nutrients to the soil, they are unable to have lasting impacts on soil health, which can lead to depletion of valuable growth-enhancing soil qualities over time.  Organic fertilizers may be locally sourced or selected from a variety of commercially available natural products.  Although organic fertilizers are commercially available from gardening supply stores, they can often be sourced more economically through the use of livestock manure, yard clippings, and plant and animal products.  Composting materials prior to application as a fertilizers lowers the risk of nitrogen burn, reduces offensive odors and lessens the risk of seeds or other undesirable components becoming incorporated into your soil.

What are pesticides and how do they work?

A pesticide is any substance or mixture of substances used to destroy, suppress or alter the life cycle of a pest. A pesticide can be a naturally derived or synthetically produced substance. A pesticide can also be an organism, for example, the bacterium Bacillus thuringiensis which is used to control a number of insect pests, or even a genetically modified crop.  Pesticides include bactericides, baits, fungicides, herbicides, insecticides, lures, rodenticides and repellents. They are used in commercial, domestic, urban and rural environments.  Pesticides are carried in rainwater runoff from farm fields, suburban lawns, or roadside embankments into the nearest creeks and streams. Occasionally they are even intentionally sprayed into waterways as part of a pest-control effort.

Pesticides control pest organisms by physcially, chemically or biologically interfering with their metabolism or normal behavior.  Most pesticides are lethal to target pests when applied at the rate specified on the pesticide label.

Some pesticides are non-lethal to the target pest. These include repellents or attractants (such as personal insect repellents), sterilising agents (which interfere with the reproductive ability of a pest), some defoliants (that cause leaf drop without killing the plant) and some pesticide products that boost the action of another pesticide without being particularly toxic themselves (such as piperonyl butoxide which may form part of pyrethrum-based insecticides).

Before you buy or use any pesticide, ask yourself whether it is really necessary to control the pest, disease or weed and whether there is an alternative to traditional chemical use.

Organic gardening methods are one way that you can reduce pesticide use and get nature to help control any pests or diseases. For example, do one or two dandelions or daisies in the lawn mean that the whole lawn needs treatment? Could you remove problem weeds by using a knife or garden fork instead? Why not remove slugs or snails when they come out at night, or use a physical barrier to discourage them?

Here are some noteworthy examples of how the effects of pesticides water pollution:

· The US EPA has found widespread contamination of waterways by Atrazine, the second most commonly used herbicide in the US. Atrazine causes feminization of male frogs even at concentrations in water as low as 0.1 part per billion. Atrazine water pollution has been noted in many countries, including South Africa, Germany, and Denmark. The Natural Resources Defense Council notes that studies indicate the chemical may be linked to a number of human cancers, including prostate cancer and non-Hodgkin's lymphoma. A University of California San Francisco study found that Atrazine can affect human reproductive and developmental processes by disrupting human hormone activity. The effect occurs at concentrations as low as 2 ppb.

· Glyphosate (Roundup), another of the world's most common herbicides, was found to cause a 70% decline in frog biodiversity and an 86% decline in the total mass of tadpoles when the glyphosate got into water.

· Pesticides have been found in well water in countries such as India, The Netherlands, Italy, Israel, Japan, Canada and Australia, and the US. Pesticide contamination of drinking water is a particular problem in rural agricultural areas where pesticide use is heavy and drinking water supplies come directly from groundwater or surface water.

· Pesticides can migrate via water into the food chain as well, ultimately being consumed by humans or animals in food.