The fall season brings winter weeds. They germinate in the fall, grow through the winter and spring, and then die in the late spring. Most people think that when the grass slows it’s growth that there is no more to do to the lawn, however, fall is the second best time to control weeds using the pre-emergent method described later. The only drawback is that you cannot seed and apply a pre-emergent weed control at the same time.

These weeds can be controlled with proper methods. The two methods used are pre-emergent, and post-emergent. The pre-emergent method is the most effective because the weeds are controlled before they emerge this way the lawn looks cleaner because you never see the weeds.

A pre-emergent herbicide is used to prevent weeds such as; Crabgrass, Goosegrass, Quackgrass, Henbit, Chickweed, Plantain, and some 30 to 40 other weeds. The timing is critical on applying pre-emergent herbicides. If you put it down to early, you miss the late summer weeds, if you wait to long to apply, you’ll miss the crabgrass. Usually the weather in your area will dictate the proper timing. When Forsythia starts to bloom in your area is a good clue as to when to apply.

Using chemicals to control weeds is a tricky matter. Used correctly, they pose no problem.(Contrary to many beliefs)More harm is done to the environment each year by homeowners trying to do something that they don’t understand than by all of the professional applicators put together. Just be careful, read the label, AND FOLLOW THE INSTRUCTIONS.

The second method of weed control is Post-Emergent control. This involves spraying the weeds after they are already up and showing. Commonly this is called broadleaf weed control because usually the weeds controlled are broadleaved. Dandelion, plantain, chickweed, oxalis, wood sorrel, wild onion and garlic, purslane, and clover are all examples of broadleaves. These have to be controlled by applying the herbicide to the leaves or to the soil as to reach the root zone of the plant.

There are many sprays available and granulated products also. The granules may be easier to apply if you’re not good with a sprayer. Sprays work much faster because you don’t have to wait for a rain or irrigate to activate the chemical. Check at your garden center or discount store for available broadleaf herbicides. Just be careful around your shrubs and flowers, they are also broadleaves and it is not hard to kill them inadvertently. I see this every year.

Eddy County Extension Service, New Mexico State University is an equal opportunity/affirmative action employer and educator. All programs are available to everyone regardless of race, color, religion, sex, age, handicap, or national origin. New Mexico State University, U.S. Department of Agriculture, and the Eddy County Government Cooperating.

Most soils, garden soils, and landscaping plots will never need the extremity of sterilization. However, in some instances such as nematode infestation, it may be desirable to completely sterilize the soil. The major drawback to this, whether naturally or chemically, is that it also kills soil organisms that are beneficial to garden and landscaping plants. However, depending on certain circumstances, it may be necessary.

It’s almost impossible to eliminate all weeds seeds, diseases, nematodes, and insects. And especially by organic or natural methods. However, it is possible to cut the population of most to just a few simply by using the heat of the sun in the hottest part of Summer. That is, in most climates. I’ll explain more on that later.

In the hottest part of Summer, usually August or July for most areas, it’s possible to raise soil temperatures over four inches deep to above 120 degrees. Kept at high temperature for several weeks, most unwanted soil elements will be destroyed.

First, till or spade manure into the surface soil as deep as you can get it. The manure will help to generate heat. Next, moisten the area and cover with clear plastic sheeting. Keep the sheeting on the ground and make sure all edges are tucked tightly, covered with dirt, or held down in another way. This will basically create an oven that will produce soil temperature often above 120 degrees. This will generally “cook” the largest percentage of unwanted soil problems. Keep covered and moist for at least four weeks.

In cooler climates where even Summer temperature don’t get very high, it’s possible that this method will actually help germinate some seeds and multiply unwanted soil diseases. It basically creates a cozy greenhouse atmosphere with good temperatures for germination.

For a smaller scale, small gardens, and smaller landscaping or garden design ideas you can have better success and possibly eliminate all unwanted diseases, weeds, nematodes, and insects. Placing soil in black pots, moistening, and covering tightly with clear plastic will produce soil temperatures in excess of 150-160 degrees. Keep covered for two weeks and make sure it stays moist. Not much can live in that.

Again, keep in mind that this also kills beneficial soil organisms. However, the tradeoff may be necessary. And you can rebuild the structure of the soil over time by adding lots of organics to the soil.