Why do weeds overtake gardens so fast?
Most plants we call weeds are uniquely programmed by nature to survive and thrive. Most propagate by seed and the worst offenders can produce tens of thousands of seeds per plant, per season.
Common lambsquarters, for instance, can easily produce up to 70,000 seeds annually per plant, seeds that can last decades if left undisturbed below the soil surface. Thus a yard already over-run with weeds is essentially a monstrously efficient weed seed producing machine!
Not all seeds sprout into weeds immediately, of course. Millions of them settle into the soil where they can wait years for a bit of sunlight to spark them into growth. That’s why well-intentioned efforts to clear a weed-ridden bed often backfire by unleashing a torrent of new weed growth, as the very act of pulling up weeds and their roots unearths underlying seeds that quickly germinate at the surface.
Particularly pernicious are broadleaf perennial weeds, such as knotweed, purslane and thistle that propagate by seed and also vegetatively, regrowing from bits of the plant or root. If you chop up these types of weeds, you merely make more of them.
Is it possible to ever “win the war” against weeds?
Yes it is, but not without a battle plan that focuses on a combination of weed prevention and routine spot action. The good news is that, once you get ahead of weeds, it becomes easier and easier to stay ahead of them.
The old garden adage hits the nail on the head: one year’s seeds equals seven years’ weeds. The weed war is truly all about seeds.
Weed prevention hinges on:
1) stopping current weeds from going to seed and
2) preventing future weed seeds from sprouting. The trick is to make weed prevention a yearly routine that, if followed, becomes increasingly easy over time.
How can I get the jump on weeds & minimize weeding all season?
Ideally start your weed prevention efforts early in the season – but understand that any time is a good time to start as there’s always a plentiful supply of weed seeds ready to sprout, given even the slightest opportunity.
First, remove any existing weeds, including the roots. Starting with this clean slate, add a layer of protective mulch to starve any just sprouted weeds of sunlight.
Next, apply a pre-emergent weed preventer such as Preen to prevent any existing weed seeds in the top layer of soil or mulch from forming roots. No roots, no weeds, no weeding. Using a combination of mulch and weed preventer provides a double whammy of control.
Periodically, a few weeds will still crop up – remove them. Re-apply weed preventer mid-season (per product instructions) to keep seeds from the current year’s weed crop from germinating, bearing in mind that many weeds set seed in late summer or fall. Refresh mulch as needed.
Each spring, as you start the process again, you’ll find fewer and fewer weeds to deal with. Following a simple seed-focused routine allows you to literally turn the corner on weeds.
What’s the difference between weed killers and Preen weed preventers?
Preen weed preventer stops would-be weeds when they’re seeds. By preventing weed seeds from forming roots, Preen helps keep a garden free of new waves of troublesome weeds. Weed killers kill existing weed plants and they work in various ways. Glyphosphate-based herbicides such as Roundup inhibit a plant enzyme that plants need to grow.
Organic choices such as salt or acetic acid (vinegar) kill by dehydration. Pouring on boiling water or scalding with steam withers and kills the leaves and stems above ground. Of these methods only glyphosate kills the roots.
How does Preen weed preventer work?
Weed preventers stop weed seeds from forming roots – so those weeds simply never happen. Preen Garden Weed Preventer’s active ingredient, trifluralin, constitutes 1.47 percent of the product, with the rest consisting of the delivery medium, small granules made of corncobs and recycled paper. Once activated by water, trifluralin bonds with soil particles to create an invisible weed control barrier just below the soil surface. The barrier stops seeds from sprouting by inhibiting cell replication in the root hairs.
In the garden, Preen remains effective for up to three months for Preen Garden Weed Preventer and up to four months for Preen Weed Preventer for Southern Gardens. Preen weed preventers do not persist in the soil, nor will they leach into groundwater. Preen’s active ingredient breaks down and biodegrades and within six months to a year or so is no longer active. (Preen Weed Preventer for Southern Gardens contains .27 percent dithiopyr as its active ingredient, which works in a similar manner).
Can I use Preen by my water garden?
Preen garden weed preventers should not be used near aquatic ecosystems. It is important to never use Preen near ponds, streams, creeks, rivers or water gardens. Nor should it be used near or in water from swimming pools, drains or sewers that may find its way into an aquatic ecosystem. While the product will not wash out of soil, avoid areas where eroding soil might wash into bodies of water. The product should be swept from walks and driveways, and care should be taken when washing tools and discarding containers.
Is there an organic weed preventer?
Corn gluten is an effective organic weed preventer. It contains amino acids that disrupt secondary root growth, thus preventing newly-germinated weed seeds from taking root.
One 100 percentorganic corn gluten option that prevents weeds for four weeks or more is Organic Preen Vegetable Garden Weed Preventer. Organic Preen uses corn gluten as its active ingredient in small application granules made of corncobs and recycled paper. Its container comes with a fliptop applicator that makes it easy to distribute the corn gluten granules evenly in the garden.
The good news for veggie gardeners is that corn gluten works best on soils that have been well amended with compost. Corn gluten is also a natural source of nitrogen, so if you use corn gluten you may need less of other types of nitrogen fertilizer.
Organic Preen can be used around established vegetables, fruits and herb plants. For obvious reasons, don’t apply a seed inhibitor over newly seeded areas, wait until plants are two to three inches tall and have set true leaves.
Organic Preen is also perfect for use right after transplanting or setting out pre-started plants. Sprinkle it on the soil surface, keeping it out of planting holes. Organic Preen can be reapplied every four to six weeks. It’s completely organic and safe for use in vegetable gardens all season long, even to the day of harvest.
Do Preen weed preventers build up in the soil?
The active ingredients in Preen weed preventers do not persist in the soil. Once applied, they bond with soil particles where they do their work, then are consumed by soil microbes and biodegrade and within six months to a year or so are no longer active. Preen weed preventers are not water-soluble and will not leach into ground water.
Do I have to stay out of the garden after watering in Preen?
After Preen granules are watered in, people and pets should stay off the area until the surface is dry to avoid tracking the wet granules on the lawn or elsewhere where they might stain porous surfaces. Once activated by water, the active ingredient in Preen is released from the granules to bond with soil particles in the top few inches of garden soil. There it creates an invisible weed control barrier. The little Preen granules still visible on the soil surface are made of corncobs and recycled paper and also break down in the soil.
The Preen label says not for use on “soils with more than 10percent organic matter.” What does this mean?
To most people, 10 percent organic matter probably sounds low for garden soil. Most people probably figure that their own garden soil has a significantly higher percentage of organic matter, especially if they amend their soil each year with compost to improve soil structure, nutrient-retention, aeration, drainage, etc.
Yet, even with routine annual boosts of organic matter, most garden soil typically contains only 3 percent to 8 percent organic matter, with 5 percent to 6 percent being the norm. The information is relevant to those who might advocate such practices as growing plants in 100 percent compost, a practice not generally advised.
To learn more about weeds, weed prevention and timely seasonal gardening tips, visit www.preen.com.
