Waging War on Weeds
By Bob Chapman
Weeds have been a problem for gardeners as far back as the time men turned from cattle grazing to farming. It seems that nothing is as frustrating to a gardener as to have a nice yard, but have the lawns, vegetable gardens, flower beds and shrubbery borders choked with weeds. Many hours of back-breaking work have been expended over the centuries to eradicate the unwanted weeds. Today we have three battle plans for waging war on weeds.
Sending in the ground forces:
OSH still offers long-handled garden hoes, short-handled ones and hand-held hoes and the ever-popular garden trowel used as the first offensive in the battle to control weeds in the garden. It doesn't take any special training to learn how to use these tools as the weeds are usually chopped off at ground level or dug out if shallow-rooted. In spite of the amount of time and effort and the cost of supporting these troops, the enemy still manages to rear its ugly head. We'll need to call in air support to aid in conquering the enemy.
Air support to aid in the war on weeds:
For the modern gardener, chemistry offers tremendous help in fighting the war on weeds. Now, the attack mode shifts. Air support or clandestine operations when the enemy is not looking means spraying or spreading certain chemicals at the proper time of the year to either kill off noxious weeds or prevent them from coming up. There are two kinds of chemicals commonly used in the battles that the gardener should become familiar with: those that are sprayed on existing weeds and those that are put on the soil to prevent weeds from growing.
• Chemicals that kill weeds are called herbicides. Some herbicides such as Finale will kill the top growth and roots of weeds immediately. Others, such as Easy Gone Weed and Grass Killer or Roundup, kill by slowly being translocated to all parts of the weed, killing the roots as well as the tops. A third herbicide widely used in waste areas where no vegetation is desired contains a soil sterilant (Easy Gone Total Vegetation Killer). In addition to killing the growing weed, this combination prevents weeds from growing for up to a year or more.
• On the market are chemicals that form an invisible barrier on the top layer of the soil (down to about an inch below the surface), killing the newly germinated seed before it can grow further. Two products are sold in our stores, Preen and Amaze. Preen is sold in a handy shaker container, making application easy. Amaze is sold in bags and must be spread with a hand-held rotary (or broadcast) spreader or the wheeled drop spreader used to fertilize lawns. These wonderful weed-preventers must be applied to areas that have been cleared of any existing weeds as they do not kill growing weeds, just the newly germinated seedling. Be aware that these weed preventers will also stop flower and vegetable seeds from growing, so don't use these where you want to grow flowers and vegetables from seed
• Broad-leafed weeds growing in lawns are easily controlled by the use of "weed and feed" fertilizers or spraying the lawn with weed killers for lawns. Many gardeners control future weed growth by spreading granular weed preventers (Preen or Amaze) over the lawn to inhibit the growth of weed seeds. Another way to prevent weeds from growing in lawns is to spread a combination fertilizer/weed preventer over the lawn in early spring to prevent crabgrass and in early fall to prevent weeds such as annual bluegrass from invading the lawn in winter.
Victory is almost at hand: ground troops and air strikes have done the visible enemy in.
Now our forces must look to a long-term method of controlling the enemy, one less costly over the long term and more of a permanent control. We don't want any uprisings; we want permanent suppression of the enemy, the ugly, noxious, nutrient-robbing and water-stealing weeds.
Suppressing the weeds using physical barriers:
Weed seeds need light and moisture to germinate and grow into mature plants. When deprived of moisture or light the seeds fail to germinate. Soil moisture is difficult to control due to the annual rains, but you can deprive the dormant seeds of needed light by blocking it with various materials.
• Landscape fabrics. The invention of a closely woven plastic fabric that was resistant to degradation from the sun while still allowing air, water and dissolved fertilizers to pass through solved the problem with the use of plastic sheets (see below). Called "Landscape Fabric" (or geotextiles), it is sold in handy rolls, making it easy to put in place. Simply roll out the fabric, overlapping it 4-6 inches to prevent having any gaps that sneaky weeds could find, pegging it in place and covering it with bark, shredded bark (called "gorilla grass") gravel or rocks of various sizes. The end result is a neat, orderly look that enhances a garden, effectively prevents weeds, helps retain water and will last for many years.
• Gravel, rocks, mulch, compost. Many gardeners do not place any physical barrier, such as landscape fabric, between the soil and the covering. Instead, they rely on the thickness of the covering to block the light from the weed seeds. The covering must be at least four inches or more thick (depending on the looseness of the material) to effectively block the sunlight. If even a little glimmer of light reaches the soil and the weed seed it will surely sprout necessitating the removal of the growing, noxious weed. The coverings do help retain moisture in the soil and maintain a more even soil temperature, making it very comfortable for shrubs and trees to grow.
• Plastic sheeting. Over the years many gardeners have devised methods to keep the weeds controlled by covering them. When the familiar black plastic sheeting came on the market many covered unused areas with it, only to find that down the road the plastic deteriorated, leaving a real mess to clean up. They found that covering the plastic sheeting with organic materials or with gravel, rocks and cobbles would work if applied deeply enough to block the sun from the plastic, BUT what they did discover was that the plastic sheeting did not allow water to go through. Pools of water would collect in the small hollows and sometimes smell pretty bad until the water dried. They also found that coverings of bark nuggets or even larger sizes of bark would float off in a heavy rainstorm.
Knowledge is power
Now you have a better understanding of the methods of waging war on weeds. You can continue to get the better of weeds in your flower beds, shrubbery borders and lawns. Determine which methods can be used to control weeds in your landscape. Use them and relax, knowing your battle against weeds can be won. The tasks in maintaining a weed-free landscaping are going to be much easier in future years.