UF/IFAS Okeechobee County Extension Service

458 Highway 98 North

Okeechobee, FL 34972-2578

Phone: (863) 763-6469

E- mail:  dfculbert@ifas.ufl.edu

March 1, 2006

Feature Article - for release the week of March 5, 2006

Dan Culbert - Extension Horticulture Agent

Organic Gardening 

Last week Okeechobee had a nice turnout at a farm field day.  Varri Green Farm hosted farm visitors who wanted to learn a little bit about what it’s like to grow vegetables using natural fertilizers and least toxic pesticides. Over 20 persons attended, including our new University of Florida Vegetable specialist, Dr. Danielle Treadwell. 

What do you envision when you hear the term "organic gardening"? Do you think of extremely large and beautiful fruits and vegetables free of pesticide residues and containing an abundance of vitamins and minerals or do you picture insect chewed leaves and fruit marred by worm holes.  Today’s column comes from Dr. Bob Black, and is designed to clear up some confusion surrounding organic gardening.

Many of us have probably used a form of organic gardening without knowing it. The addition of manure or compost into a garden bed, the addition of peatmoss, ground bark or leaf mold to a planting mix, using bone meal to fertilize bulbs and squirting aphids off a plant with a hose are all forms of organic gardening.

Both organic and conventional gardeners agree on the value of the addition of organic matter to the soil.  Organic matter makes soil easy to work, increases its nutrient and water retention, improves soil atmosphere, promotes increased biological activity and adds nutrients to the soil.  

A major difference of opinion between conventional and natural gardening is with the method of supplying nutrients to the plant. The organic gardener uses only organic materials (e.g., animal manure, blood meal, cottonseed meal and wood ashes) while the conventional gardener uses inorganic materials (commercial fertilizer).  Since organic fertilizers release nutrients very slowly, there is less chance of fertilizer burn.

However, the nutrient content of organic fertilizers is far less than that of commercial fertilizers, so large amounts of organic fertilizer are needed to do the job of a small amount of commercial fertilizer.  Whether you apply an organic or commercial fertilizer, the plant roots absorb nutrients from both in the same elemental forms.

The other major difference between organic and conventional gardening is the method of pest control: Organic gardeners do not use inorganic pesticides. Instead, they use natural forms of control.

One form of natural control employed by organic gardeners is by physical means. This may involve picking an insect off a plant and squashing them. Washing insects off plants with a strong water spray from a garden hose is another method of physical control.

Natural control of harmful insects can also involve natural predators. Some insects such as ladybugs, praying mantises, lacewing and trichogramma wasps feed on harmful insects.  These insects may be purchased and placed in your garden.  However, there is no guarantee that they will remain there.  They may stay and destroy many harmful insects or they may leave soon after released.

Other predators of harmful insects are frogs, toads, lizards, salamanders, snakes and birds.  Birds can be attracted by placing bird baths and feeders in your garden. However, not all birds eat insects. Some birds eat fruits and seeds and they can be very destructive in your garden.

Spray preparations are another method of insect control. Soapy water sprays and oil sprays are effective in controlling many harmful insects. There are sprays which can be purchased that contain diseases that effect insect pests, such as Bacillus thuringiensis (i.e. “B.t”) and milky spore disease.  These sprays are fatal to insects, but are harmless to people.

Spray preparations derived from plants have been reported to help manage insects. Some of these botanical sprays are toxic to insects; others are simply offensive to them and discourage them. Common toxic botanical sprays include: pyrethrum, sabadilla, rotenone and ryania.  The sprays which are offensive to insects consist of home-made extracts from juices of plants such as onion, garlic, pepper and marigold.

Some organic gardener's believe that planting marigolds near other plants will keep away harmful insects. There is no scientific evidence to prove or disprove this at present. However, there is evidence that marigolds will reduce nematodes within a 3-foot radius of the plant.

Organic gardening is not for everyone. Those who pursue organic or natural gardening approaches should expect to have more chewed leaves and plan on devoting more physical work. For those who have the time and are willing to exert the extra effort, organic gardening may be both productive and rewarding.

Commercial growers that use organic production methods are required to prove that they are using practices approved by the USDA.  The term “organic” is backed up by a considerable investment on the part of the grower.  Small scale producers such as Varri-Green Farm may not be able to spend the amount of required fees for this certification.  Instead, they have chosen to follow all the organic practices but avoid fees and paperwork by being certified as “Naturally Grown”.  Their certification is just as valid as USDA organic, their record keeping is just as rigorous, their practices are equally safe, and their products are absolutely delicious.

I’ve placed more information on our Okeechobee web page, http://okeechobee.ifas.ufl.edu.  If you need additional information on organic gardening, please email us at okeechobee@ifas.ufl.edu or call us at 863- 763-6469.  Local residents can visit our local green market on Thursday evenings in downtown Okeechobee.  Others can stop by our office at 458 Hwy 98 North in Okeechobee, and visit our Okeechobee County Master Gardeners from 1 to 5 PM on Tuesday afternoons. Happy Gardening!

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Trade names, where used, are given for the purpose of providing specific information. They do not constitute an endorsement or guarantee of products named, nor does it imply criticism of products not named. The Florida Cooperative Extension Service - Institute of Food and Agricultural Sciences is an equal opportunity/affirmative action employer authorized to provide research, educational information, and other services to individuals and institutions that function without regard to race, color, sex, age, handicap, or national origin.  Florida Cooperative Extension Service / IFAS / University of Florida.  Larry A.  Arrington, Dean Last update: 03/01/2006 .  This page is maintained by Dan Culbert 

references

Black, Bob. Organic Gardening. Gainesville:   UF/IFAS Environmental Horticulture Department webpage, 2006. http://hort.ifas.ufl.edu/gt/organic-garden/organic.htm 

Certified Naturally Grown webpage, New Paltz, NY, 2006.  http://www.naturallygrown.org/

Stephens, James M.  Organic Vegetable Gardening CIR375  Gainesville: UF/IFAS Extension Service, May, 2003. http://edis.ifas.ufl.edu/VH019