Roanoke Times
                 Copyright (c) 1995, Landmark Communications, Inc.

DATE: THURSDAY, March 15, 1990<                   TAG: 9104050019
SECTION: LAWN & GARDEN                    PAGE: 1   EDITION: EVENING
SOURCE: John K. Arbogast / Special to the Roanoke Times & World News
DATELINE:                                 LENGTH: Long

PLANTING

Projects designed to reduce soil and water pollution from horticulture activities have been termed "best management practices." Many of these are simply common-sense measures that some gardeners and homeowners already practice. Concerns such as global warning, chemical contamination, loss of natural forests and others make us conscious of the need for better management as we cultivate gardens, lawns and landscapes.

An important cultural practice is to select plants to avoid problems. For the vegetable garden or fruit planting, look for varieties that are resistant to diseases or less tasty to the insects. This information should be on seed packets and in garden catalogs.

For turf seeding, use only recommended seed varieties that have been developed for strength rather than a variety listed as "common whatever."

For additions to the landscape, do not add plants that are known to have problems, such as roses, which are very susceptible to a host of diseases, or be sure to look for resistant varieties if available.

An equally important horticultural practice is to select an appropriate site for all plants; this guideline simply tells us to locate vegetable gardens in sunny spots with well-drained, workable soil, and ornamental plants in the necessary sun or shade, again with decent soil. The bottom line is that plants that are experiencing weak growth are more likely to get insect and disease problems.

Gardens, flower beds and some landscapes that are on slopes are subject to soil erosion. One preventative step to that is to keep the soil covered with either mulch, plants or actively growing grass. This will reduce the impact of heavy rains or waterings and allow more of the water to enter the ground slowly. Soil erosion, when it does occur, carries more than particles of earth. Fertilizer elements and chemical residues go with it.

Landscapes on slopes can be redesigned to include terraces which will be an attractive way to reduce surface water runoff. Terraces can be of planting beds only with sections of moderately sloping grass between terraces, or the terraces might include both turf and landscape plants.

This horticulture for the '90's does not rule out chemicals. What is suggested for homeowners as well as agricultural producers is a practice called "integrated pest management." IPM utilizes cultural and biological practices which prevent or help control pest problems so that fewer chemicals are needed for successful pest control.

The objective should be to suppress pest populations below the level that will cause economic or aesthetic damage to our plants. In other words, don't try to kill every insect.

IPM methods include:

Varying planting dates to avoid peak pest periods; for instance, summer squash can be planted as early as possible so some produce can be harvested before the squash vine borers hit in July;

Vary selection

Space plants properly in the garden, flower bed or seed bed to encourage vigor and appropriate air movement

Monitor plants so that problems can be noticed as they begin and removed. For instance, bagworm bags can be pulled or cut from landscape plants in the fall or winter to reduce the number of bagworm eggs hatching in spring.

Rotate crops in the garden and flower beds.

Set the cutting height for a bluegrass or fescue lawn at 2 1/2 to 3 inches to reduce the need for weed-killers; turf cut short is more prone to weed growth.

Use sanitation, which means removing insect-infested, diseased or dead plants from the garden or landscape right away.

Some biological practices considered part of IPM that homeowners are learning include introducing or allowing natural enemies of pests to exist, such as praying mantises and ladybugs, as well as utilizing natural diseases of pests, such as Milky Disease spore powder that can be applied to turf to infect Japanese beetle grubs.

When chemicals must be used, certain practices are suggested.

First, read the label. Proper rates and methods of application, safety procedures and approved uses should be strictly followed. Use the right chemical for the right job.

Better management needs to be practiced when fertilizing lawns, gardens, flower beds and ornamentals. Apply nutrients at the best time for individual plants, in the precise locations where the nutrients will be available, and only in amounts needed for good growth flowering and/or fruiting. Excess fertilizer not used by the intended plants may be a source of water pollution. A good example is excess fertilizer applied to some lawns the result may be a dark green color frequent mowing, removal of lots of rich clippings, and possible turf roots that can't keep up with the top growth.

In order to get the maximum benefit from the fertilizers applied, it is a good practice to take soil tests every two to three years to monitor ,the soil pH. This is the level of acidity or alkalinity of the soil. Specific plants have known pH levels at which they grow best. These levels should be maintained because the pH of the soil controls the availability of fertilizers applied to the plants growing there. Lime is recommended to reduce the acidity of soil and sulfur is used to lower the pH. In simple terms, nutrients may be plentiful in soil but can't be used by the plants growing there if the pH is not at the proper level. There is no way to look at a soil and guess at the need for lime. Thus, the old-fashioned recommendation to take a soil test is critical.

Maintain a proper level of organic matter in the soil for gardens and flower beds to encourage a healthy soil and help make nutrients available to plants. Organic materials used as summer mulch around annual flowers and vegetables should be turned under the soil in the fall.

To sustain the earth that grows lawns, flowers, gardens or landscapes, try to return to the soil some of its output where possible. In the vegetable garden, rototill or dig into the soil plant parts that did not have diseases or pests after those vegetables have been harvested. Large vegetable plants should be easier to turn into the soil if they are first chopped or cut up.

\ John Arbogast is the extension agent for Roanoke