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Avoid pesticides for greener results

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Wednesday, April 16, 2008

Q. I do not like to use pesticides in my landscape and I try to manage my gardens and trees naturally. It takes a great deal of energy to pull out weeds by hand and I use mulches wherever I can. Can you provide some advice for someone who wants to have a healthy landscape and not harm the environment? -- Monique P., Morristown

A. This is an excellent question as Earth Day approaches. There are many things that you can do to reduce the excessive or unnecessary use of fertilizers, pesticides and water in the landscape.

"Earth-wise" lawn and landscape tips
-- Soil preparation: In order for plants in your yard to get a healthy start and remain healthy, you need to provide a healthy soil environment. First, take a soil test to determine pH and nutrient levels. Before planting, relieve any compaction problems. Amend the soil with well-rotted compost or peat moss. Mix organic materials into the top 10 inches to 12 inches of soil before planting and adjust soil pH according to the needs of the plant. Remove excess moisture with proper grading or installation of drainage systems.

-- Plant selection and placement: Choose plants that will perform best in your yard based on the amount of sunlight, soil conditions, space and planned maintenance they require. For instance, ericaceous plants such as rhododendrons and azaleas perform best in areas with 15 percent to 30 percent shade and organic soils with adequate drainage. Dogwoods also prefer partial shade and will struggle in full sunlight if not kept adequately mulched and watered.

-- Select pest-resistant plants: Look for lawn grasses that contain endophytes, natural fungi found in select cultivars of fescues and ryegrass. Endophytes will protect grasses from surface-feeding insects, eliminating the need for most insecticides. Turf-type tall fescues and hard fescues are excellent grasses for low-maintenance lawns. These tough grasses require less water and less mowing, and many contain endophytes. Visit our website or call and talk to a master gardener to learn about the best plants for your area. (See "resources" at the end of the article.)

-- Mulch and groundcovers: It may be wise to replace portions of the lawn with groundcovers, especially in shaded areas. Visit our website for a complete list of appropriate groundcovers. Put 2 inches to 3 inches of organic mulch around trees and shrubs, out to the drip line, to conserve moisture and protect roots. Never pile more than 3 inches of mulch over roots or put additional soil on top of roots -- you may decrease oxygen levels to the roots and harm the plants.

-- Water in the morning: Irrigation for lawns and landscapes is best done very early in the morning to conserve moisture and help prevent foliar disease problems on all garden plants and lawns. Extended periods of wetness on lawns can increase the potential for foliar diseases. 

-- Don't overfertilize: Recycle grass clippings back to the lawn to provide one-third or more of your nitrogen fertilizer needs. Research has shown that grass recycling returns a steady supply of nutrients back to lawns. Returning grass clippings to the lawn also prevents valuable organic materials from ending up crowding landfills.

Use slow-release or 50-percent organic-based fertilizers. Slow-release fertilizers will allow a steady supply of nutrients over a longer period and reduce the potential of leaching fertilizers into lakes, streams, ponds and groundwater. Also, reduce fertilizer use near any body of water and provide a grass buffer strip between application areas and water. Provide the bulk of lawn fertilizers in the fall so nutrients meant for grasses don't end up enhancing weed growth.

-- Reduce plant stress: Keep mower blades sharp to help reduce foliar diseases. Lawns will recover faster with sharp blades and early-morning watering. Do not fertilize or apply herbicides to lawns during hot weather or around stressed plants. Even herbicides that are labeled for lawns and use around other plants can cause damage during heat and drought stress. Reducing compaction of soils with core aeration can help reduce long-term weed problems in lawns. Topdress lawns with `-inch to ¼-inch of compost or peat moss several times a year to add valuable organic matter and remember to recycle clippings. Have a trained professional prune large trees and shrubs. Be sure to prune plants properly and at the right time of the year so pruning cuts heal rapidly.

-- Proper plant culture and management: Learning how to properly care for plants can reduce pests and disease problems and, likewise, the need for pesticides. Mowing lawns to 2½ to 3 inches and watering, fertilizing and renovating them properly can help increase the density and vigor of lawns to help them out-compete weeds.

-- Alternative pest controls: Look for grasses that contain endophytes. Parasitic nematodes can be purchased by mail to control white grubs in lawns. These beneficial microscopic organisms can provide adequate control in many situations in several days and are best applied the beginning of August in our area. Milky spore can provide control for Japanese beetle grubs and may take several years to control serious grub infestations. The use of corn gluten at this time of year has been used successfully by some to prevent crabgrass from germinating. Results with corn gluten are mixed in research trials, but it may be worth trying in your landscape.

Come to our cooperative extension seminars or become a master gardener so you can help others be better stewards of their environment.

EARTH event: Music, educational demonstrations and tours will be offered at a free Earth Day celebration Tuesday from 4 to 7 p.m. at the EARTH Center, 42 Riva Avenue in South Brunswick. Bring a picnic basket and sit in the park, listening to music, or learn about composting, recycling and environmentally sound gardening and landscape care. There will be fun activities for the whole family. I will give an hourlong lecture on "earth-wise" lawn and landscape care at 7 p.m. For more information on the event, call Denise at (732) 398-5262.

Resources: For more information on plants and gardening, visit njaes.rutgers.edu or ifplantscouldtalk.rutgers.edu.