Project: Green - Steep learning curve in pest controls, fertilizers

The challenge. How sustainable pesticides and fertilizers are used differs from how synthetics are used. A major goal is to keep beneficial insects, bacteria and fungi healthy. That places a break on both categories, because if the pesticide or fertilizer is too broad or intense, it can kill beneficials. Knowing what can be used and what cannot requires more understanding from both customers and retailers.

Insecticides

Natural insecticides come in three forms: powder/dust (ground up, dried seeds, flowers, roots, etc.), extracts (oils, resins) and isolated and purified compounds. Although pesticides are made from natural ingredients, they are still pesticides and some can be harmful. U.S. EPA regulates these pesticides just as it regulates synthetic pesticides.

Bacillus thuringiensis (Bt). Bt is the most common microbial control. It attacks leaf- and needle-eating caterpillars once in the stomach. Feeding stop is within hours, although death may not occur for a few days. It’s considered safe for wildlife, and some formulations can be used on food crops. However, it degrades within a week -- even within 24 hours for some newer strains. Also, it can be controversial due to labs using Bt genes to genetically modify plants to make them more pest resistant.

Bacillus popilliae or B. lentimorbus. The bacterium is also known as milky spore disease and is a control for Japanese beetle grubs.

Citrus oils. Citric oils, made from citrus peels, destroy the waxy coating of insects’ respiratory systems and is one of the more effective organic controls. It can harm aquatic invertebrates, however, so it should not be used near streams, ponds, etc., nor be poured into the sewage system.

Diatomaceous earth/silicon dioxide. Diatomaceous earth is an abrasive powder that cuts the exoskeleton of crawling insects. If kept dry, it has a long shelf life. Insects that ingest DE die within 48 hours. On the negative side, it can cause lung irritation to applicators, so a mask is recommended.

Hot pepper wax. Hot pepper wax repels aphids, cabbage loopers, beet armyworms, spider mites and whiteflies. It lasts up to 30 days and does not wash off easily in rain or irrigation. Warning labels say to avoid use on variegated African violets, sweet basil, parsley, Dicentra exemia and fruit trees when in bud until after petals fall.

Insecticidal soaps. Insecticidal soaps are primarily salts of fats and oils found in animals and plants. Oleic acid, made from olive oil and other vegetable oils, is especially effective as a pesticide. Insecticidal soaps work by dehydrating soft-bodied insects. Some gardeners make their own soaps at home, using ingredients that can be harmful to plants and animals. Insecticidal soaps require application every seven to 10 days to infested areas. Like horticultural oils, soaps are applied as sprays, diluted to 1 percent to 3 percent concentrations.

Horticultural oils and sprays. Horticultural oils work by coating insects’ airways, as well as eggs, and suffocating them. Look for products made with organic oils, such as those produced from sesame seed, neem seed, rosemary and fish oil, as opposed to petroleum-based oils. They can be used on food crops. However, some plants are sensitive to oils and can be damaged, especially in high temperatures or low humidity. Do not combine with sulfur. There are two primary types of oils, named for when they are used: summer oils and dormant oils. Dormant oils are stronger but have a higher risk of burning foliage, hence the requirement to apply during the dormant season.

Neem oil. The active ingredient in neem is both a feeding deterrent and a growth regulator. Neem oil comes from the neem tree, Azadirachta indica, which grows in arid tropical and subtropical areas around the world.

Nicotine alkaloid. One of the oldest insecticides, nicotine controls aphids, thrips, spider mites and other sucking insects. However, it’s toxic to warm-blooded animals and is absorbed through the skin, so gloves should be worn and pets and children should be kept away from application sites. It should not be used on roses.

Other oils. Several products on the market are extracts from plant material, including garlic, clove, cedar, lavender, eucalyptus, pennyroyal and citronella. These oils are not to be confused with horticultural oils. They work both by repelling insects from eating, and by smothering insects. Most certification programs prohibit using synthetic methods for extracting.

Pyrethrins/pyrethrum (African chrysanthemum extract). Pyrethrins disrupt insects’ nervous systems and are made of the ground-up flower head of Chrysanthemum cinerariefolium, which mostly is grown in Kenya. Most pyrethrins can be toxic to cold-blooded animals, so choose areas for application carefully. Don’t confuse pyrethrins with pyrethoids, which are synthetic compounds based on pyrethrins.

Rotenone. Rotenone is both a contact insecticide and a stomach poison that controls beetles, weevils, slugs, looper caterpillars, mosquitoes, thrips, flies and mites. However, it’s a highly controversial insecticide due to studies that link rotenone to Parkinson’s disease and is currently restricted.

Spinosad. Spinosad is derived from a new species of bacteria discovered in 1982 by a vacationing scientist in the Bahamas. When the organism is fermented, it creates a compound that kills insects. When ingested, spinosad affects the nervous system and results in death within a day or two. It’s touted as a Bt replacement.

Fungicides

Bordeaux mixes. Bordeaux mixes are a combination of copper sulfate and hydrated lime. It’s best applied before leaves emerge in spring. Burning can occur when the temperature is below 50°F and in high humidity. Excessive use can build up copper in the soil.

Copper sulfate. Copper works as a preventative only. Apply when existing leaves can dry quickly. It’s toxic to fish and aquatic invertebrates, so do not use near streams or ponds. Copper will not break down in the soil.

Lime sulfur. Lime sulfur controls foliar disease as well as mites, psyllas and some sap-eating insects. Do not overlap with horticultural oils.

Streptomycin and terramycin. These are fungal-derived antibiotics and are used to treat bacterial diseases.

Sulfur. Sulfur controls mites and prevents foliar disease. Do not apply to plants treated with horticultural oil within the last four weeks. Sulfur is corrosive to metal, so it should be applied with a plastic sprayer.

Herbicides

Organic weed control is very different from traditional control. Instead of being able to point and shoot, organic weed control requires that the soil remain healthy and full of beneficial organisms.

Systemic. While several methods have been tested, there are currently no proven systemic organic herbicides that work in a similar manner to Roundup.

Contact. Citric acid, acetic acid (key ingredient in vinegar), clove oil and cinnamon oil are examples of contact herbicides. These need repeat application. The level of concentration of the active ingredient is important. Table vinegar, for example, is about 5 percent acetic acid, whereas herbicide levels are much higher.

Suppressant. Mulch/compost, corn gluten, landscape cloth/mats work by using a layer of material to prevent weeds from reaching sunlight. The exception is corn gluten, which works by dehydrating tender shoots as they emerge from the soil. For mulch or compost to work as a weed control, most experts recommend a 4-inch layer. Corn gluten breaks down fairly rapidly and will require more than one application.

Physical. Flame and steam work by bursting plant cell walls, which burst at about 130°F. Flame is used by growers and obviously isn’t going to be practical (nor legal, most likely) for homeowners. Like contact herbicides, steam and flame controls affect only those parts of the plants exposed, not the roots.

Fertilizers

Organic fertilizers step away from synthetic emphasis on nitrogen, phosphorus and potassium (N-P-K). While those elements are included, they are in much lower percentages than in synthetic fertilizer. The remaining material in the fertilizer is made up of organic material that includes many of the trace ingredients also needed by plants.

Organic fertilizers come in three main forms.

Plant derived. Composts, seaweed/kelp, dry molasses, ash, whey, alfalfa, cornmeal and cotton seed mill.

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Animal derived. Manure, bone meal, hoof and horn, fish meal, fish emulsion, shellfish meal and worm castings.

Minerals. Green sand (from ancient sea beds), lava sand, mine rock phosphate, sulfate of potash and limestone.

- Carol Miller

May 2008

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Have a thorough understanding of local soil conditions. Your extension agent can tell you what the variations are in your area. Look for more than the traditional checks of pH levels and N-P-K levels. Look also for trace minerals. If your area is high in calcium, for example, magnesium will likely be low, which can block other elements from being absorbed by plants. Ask about which amendments correct such problems, and make sure you carry those items and explain to your staff why they’re on the shelf.

Understand local pests. Pests are not as highly localized as soil conditions, but you could definitely create a “usual suspects” list. Take the time to thoroughly understand how these pests reproduce, develop and feed. Then do the research on recommended natural treatments so you understand how they work.

Embrace shelf talkers. Designers will tell you to not have more than two or three shelf talkers per aisle, since they clutter up the visual presentation. When it comes to sustainable products, however, feel free to break that rule. In fact, you should have a shelf talker with every sustainable control and fertilizer product you carry. The learning curve for these products is considerable. Customers don’t want to pick up every product to read the small print on the label. If you have signs that explain what the product does, customers can make decisions more quickly.

Organize the department in a customer-friendly way. Just because the ingredients are new to customers, their function isn’t. Organize the products just as you would synthetics -- by function, not by lumping all natural controls together under one sign

Have a create-your-own area. You will find quite a few customers want to use recipes to make their own treatments. This is the more established way to do organic gardening, where every organic expert has his or her own recipe and shares it with fans. Recipes are part of the reason many gardeners found organic gardening intimidating. Those customers will want the preassembled products. But there are plenty out there who will want the basic ingredients to assemble their own (or a favorite guru’s) formula. If you separate the dried molasses, kelp, corn gluten, etc., from premixed products, make sure you have a few good recipes displayed with them.

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In organics, it costs customers a little more to get going in their yard. But when harmony comes to that landscape, when the ladybugs come back, you don’t have to spray as often, you get fewer exotics. The goal is sustainability. I don’t want them coming back looking for a spray.

This is the basis for the organic gardener -- a well-adapted plant, put in the right place, requires less pesticides and fertilizers. No matter what you do, if you put a tomato in the shade, it’s going to get sick.

We have a lot of new people coming in and they surrender themselves when they get here, and that is part of what we do. We take them through a cycle of learning, and they become good organic gardeners.

There’s so much out there on the Web. By the time customers come to me for products, they’ve made up their mind. We don’t lose money or sales because I don’t have Roundup. I’ll tell them, “If you have weeds in the yard, then it’s not healthy. Let’s change the mowing cycle to interrupt the seed cycle.”

And soon his yard is looking great and a neighbor starts asking about it. A pretty yard is our best advertising.

But success is the key. In some cases where I have the doubting Thomas, I’ll give them compost to use in a 10-by-10 area and ask them to use their best fertilizer next to it and compare results.

I’m more than happy to share techniques and sources with other retailers, even those near by. I want everyone in town to be in on this. I’m constantly teaching, at shows, on TV, on the radio. I’m a teacher, and I love to go out and teach so everyone can understand the language of sustainability. The other businesses in town can put me out of business by knowing how I do it. But I would be OK with that because I have done what I set out to do.

Store resources

Useful Web site. If there’s something new or something I’m not familiar with I go to www.beyondpesticides.org.

Book. Rodale Press has an encyclopedia so you can look up a disease and know how to treat it.

Shelf talkers. Shelf talkers are one of the best things. I’m a firm believer in signage.

Homemade reference book. We have a loose-leaf binder that holds information from different companies that you can look up and read it right there in the shelf. It’s not just for customers. Our new hires can do the same thing.

Reference sites on the Web. I’ve set up a computer with all the Web sites with information -- Cornell, Texas A&M, a fruit tree Web site, etc. I show it to the customer. It’s a computer program I developed that allows you to look up anything very quickly. I’m almost at a place where I can sell that program to nurseries, except that it’s very regional.

Microscope. I use a microscope to look at pests or diseases customers bring in. The diagnosis happens quickly, and we can put the product they need in their hand. We want to be right.

For more: Natural Gardener, (512) 288-6113; www.naturalgardeneraustin.com.

- John Dromgool, Natural Gardener, Austin, Texas

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Growing media

Growing media don’t seem like they should be that tough of a product to add to your sustainable line. By and large, all growing media come from natural sources. But what exactly is in growing media, and are the pros and cons to the products?

Ingredient	What is it?	Pros/cons
Peat moss	Sphagnum, hypnum (also called hypnaceous), reed-sedge, peat humus	Pro: Of the four categories, sphagnum works best as a growing media, although hypnum is usable, according to Cornell University research. Water retained in the moss is readily available to the plant, and the moss structure provides good aeration. Reed-sedge and peat humus do not retain water for root uptake or increase drainage significantly. Con: Peat moss is highly controversial for many conservationists. First, it can be found mostly in Canada and states that border Canada in the U.S., which adds shipping costs and fuel use. Also, harvesting from wetlands disrupts bird populations and removes a prized resource from those areas.
Leaf mold	Layers of leaves (generally maple, oak and sycamore) and soil are composted with nitrogenous compounds fro 12 to 18 months.	Pro: Improves aeration, drainage and water retention. Con: Despite low price and availability, not used often
Sawdust	A wide variety of trees are used for sawdust.	Pro: Readily available and recycles lumberyard byproducts. Con: Quality varies with the tree the dust is derived from. Also, sawdust often is not decomposed enough to be ideal for plant nutrition.
Barks	Byproduct of the pulp, paper and plywood industry. Hammer milling and screening provides small enough particle size to make bark an appropriate growing media.	Pro: Similar benefits to sphagnum moss, according to Texas A&M University.
Bagasse	Byproduct from the sugar industry. It’s shredded or composted.	Pro: Increases aeration and drainage of growing media. Manufacturing costs are minimal. Con: The high sugar content results in rapid microbial activity, decreasing durability and influencing nitrogen levels. In limited use.
Rice hulls	Byproduct of rice milling.	Pro: Lightweight, improves drainage. Con: Resistant to decomposition.
Sand	Sand ranges in particle size from 0.05 mm to 2.0mm. Medium and coarse particles are best for growing media.	Pro: Improves drainage. Low cost. Con: Heavy weight in larger containers. Weight contributes to high shipping costs.
Perlite	Volcanic in origin. It’s crushed then heated until water within expands and creates a powdery substance.	Pro: Increases aeration and drainage. Lightweight and consistent. Con: Tends to float to the top of a container when watered. Can contain potentially toxic fluorine levels.
Vermiculite	Mineral heated to approximately 745°C, resulting in light, worm-shaped particles.	Pro: High water retention; Helps in aeration and drainage. Does not float to the top of containers during watering like perlite. Con: Less durable than sand and perlite. Some mistake it for polystyrene, which is added to many growing mixes.

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Coconut fiber pots

Ecosource Home and Garden launched its third line of biodegradable pots, called COIR, made from sustainable coconut fiber. The line supplements the greenPots line (from rice hulls) and Enviro Collection (from bamboo). Boasting organic texture juxtaposed with contemporary styling, COIR pots fill a demand for larger containers – the largest is 24 inches wide.

Soilless growing medium

Triumph Plant Co. announced that Sterling Farms of India received certification by the Indian Organic Certification body for its Neopeat coconut fiber potting medium. Neopeat is an organic soilless growing medium for horticulture and floriculture Its benefits include high water-holding capacity, which allows less-frequent watering, and improved aeration and microbiological activity.

Composters

Feelgood composters from Exaco Trading Co. are made in Germany. Their pyramidal design has proven to be very successful in making top-quality compost. Two sizes are available: regular (90 gallons) and jumbo (170 gallons). Feelgood composters are made from 100 percent recycled plastic.

Growing medium amendment

PBH Nature’s Media Amendment, used to replace perlite in growing media, has received verification from Washington State Department of Agriculture as a registered material for use in organic agriculture. WSDA verifies compliance with USDA’s National Organic Program and makes it suitable for use in certified organic food production and handling.

Compost tea bags

Merrill’s Organic Compost Tea is an all-natural alternative to chemical fertilizer and creates nutrient-rich tea in minutes for all kinds of plants. It is the first compost tea in an easy-to-use teabag. Made from Merrill’s Rodale Organic Gardening Certified poultry compost and other organic ingredients, the product is all natural, organic and chemical-free.

Sustainable plant tags

Horticultural Identification Products (HIP) introduced two sustainable plant tags. EcoTags are a degradable alternative to traditional plastic plant tags. The rigid tags maintain integrity until buried in compost or disposed of in a landfill. Tags disintegrate in one to five years. BioTags are produced using technology that relies on bio-based products, such as corn and soybeans, rather than fossil fuel-based resins. Degradation takes approximately one year.

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