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Six Steps To Weed-Free Perennials

Gerald Almy

It’s a sickening feeling. You put in long hours of hard work on your food plot—removing rocks, fertilizing, tilling, cultipacking, sowing seed, and carefully nurturing the plants until you have a gorgeous field of nutritious forage for the deer on your land. Then gradually you watch as weeds and grasses take over. Soon your lush green field becomes barely recognizable as a food plot for deer. Every weed and grass imaginable seems to have found a home in the plot, and they are slowly, depressingly squeezing the life out of it.  

And it’s not just aesthetics that are at stake. Those weeds and grasses are competing directly with your planted crop for sunlight, nutrients and moisture—the three building blocks of a successful food plot. 

That’s a scenario I’ll bet every gamekeeper has experienced. It may take a few months, or if you’re lucky a few years, but eventually weeds and unwanted grasses will invade most perennial food plots such as alfalfa, chicory, and clover. In fact, I’ll go out on a limb and state that weeds are the food plotter’s number one enemy.

The outcome doesn’t have to be as bad as the picture painted above. Instead of being defensive and reactive about weeds, go on the offense. No, you’ll never totally eradicate weeds and competing grasses from perennial and annual food plots. But you can knock them way back. By keeping weeds under control you’ll boost the tonnage, palatability and longevity of your plots. Take an active, aggressive approach with the six-prong attack outlined below. 

deer in a food plot

1. Properly Prepare The Soil

This step is a preliminary one. It puts you ahead of the game of combating weeds by making the environment less conducive to their growth and more favorable for the growth of your target plants. This is the basic step of doing a soil test and following the instructions for bringing pH and nutrient levels up to the optimum level by applying lime and fertilizer.  

Most weeds and grasses thrive in acidic soils, so bringing the pH close to neutral (7.0) with lime is one of the best ways to help your crop grow strong roots, extract nutrients from the soil and out-compete these invasive plants. Similarly, applying phosphate, potash, and a small amount of nitrogen will help the target crop thrive. And don’t forget sulfur and boron if required, as well as micro-nutrients such as manganese, zinc and copper. A thickly growing stand of clover, chicory, or alfalfa will help crowd out weeds and keep them from gaining a foothold.

2. Apply Glyphosate

Before planting, it’s crucial to kill as many weeds and unwanted grasses as possible. Nothing tops glyphosate (Roundup) for this purpose. Using an ATV or tractor, spray or use a Weed Wiper, applying the strongest dose recommended. Make sure you cover all areas thoroughly. It’s easy to just get a partial kill if you apply lightly or haphazardly. Make sure the herbicide includes a surfactant.   

You’ll see some die-off within a few days but it may take 7-14 days to get a complete kill. If you see more than a hint of green at that point, spray again. Wait another 5-7 days, then till the soil to kill remaining weeds by uprooting them. This may allow more unearthed seeds to sprout, so you may have to spray again with glyphosate. Till several times again to get the bed well smoothed for planting. This is about as weed-free as you can get at this point.

3. Utilize Selective Herbicides When Necessary

In spite of your efforts above, once the plot is growing, weed and grass seeds in the soil that were unearthed during tilling will sprout and seeds will fall in from surrounding areas. Usually within months, but definitely within a year or two, you’ll be facing the problem of weeds invading your clover and alfalfa plots. Grasses will show up too, and often they’re more problematic than broadleaf weeds. The best way to tackle these competitors to your crop is to hit them hard and early with Weed Reaper or similar grass-killers such as Arrow, Select or Poast. Two main chemical bases are used, sethoxydim and clethodim. Many food plotters feel the clethodim products work slightly better, but both will significantly reduce your grass and grassy weed problems.
If the herbicides don’t come with it, be sure to add a surfactant so it will adhere and absorb into the target plants efficiently (Weed Reaper comes with surfactant). Follow directions carefully and spray when the grasses are just 3-5 inches tall. If they’re taller than that it will be hard to get a complete kill. Mow them down and apply when they start to regrow again in 5-7 days.
Be patient after you spray. You probably won’t notice any immediate effects. In fact, it may take 2-3 weeks for the complete results of grass spraying to be visible. Do this spraying in spring and then again in late summer or early fall to kill grasses that didn’t completely die off and others that emerged later, after your initial spraying. 

If broadleaf weeds are a problem, you should also spray for them at this time with herbicides such as Butyrac 200 (2, 4-DB) or similar products. Your county extension agent or the local farm co-op can likely offer good advice on what local land managers have found effective on the specific problem weeds in your area. A quick phone call is well worth the effort. Check the directions carefully to see whether they can be mixed with other herbicides. Usually separate applications are recommended.

4. Mow

If you get an effective kill with selective herbicides, or if your plot is young and hasn’t been invaded heavily by weeds, you may not have to mow as often. If the deer keep your alfalfa or clover browsed down enough, I'm of the opinion there’s no need to mow at all. However, mowing also stimulates stolon production and promotes more attractive, palatable growth on your perennials. When to mow and how aggressive to cut is more of an art than a science.
Chances are, though, some weeds and grasses were not killed by your preliminary Roundup spraying and the follow-up selective herbicide application. As soon as those unwanted plants get taller than your clover or alfalfa, it’s time to clip them down to reduce their competition with the crop. This step is especially valuable just as these plants are starting to form seed heads, so they aren’t allowed to reproduce and compound your problem.
Set the mower just higher than your crop. If the clover is flowering, set it low enough to clip off most of the blossoms, too. That makes the plants produce more succulent forage and keeps them from wasting energy growing seed heads.
I mow my clover plots anywhere from zero to six times per year. Generally you’ll want to cut it at least 2-4 times per summer to keep eradicating or knocking back weeds and grasses as much as possible.

5. Spot Spray

Sometimes weeds are so spread out that you don’t really need to spray an entire plot. This is where hand sprayers come in. You can use a simple hand-held one or two-gallon sprayer, or BioLogic makes a terrific Backpack Sprayer that holds a larger amount of herbicide and uses padded straps to support the weight of the product comfortably on your shoulders. 

In some cases a selective herbicide might be useful for this task, but if you’re individually spraying single unwanted plants, glyphosate is often the best way to go. I like to walk so I get some exercise while I’m doing this individual weed-killing, but you can also slip along in a golf cart or ATV, spraying one weed at a time. Using this tactic I’ve all but eradicated thistles from my land over several years of effort and cut back substantially on pigweed and several other harmful invasive weeds.
Hand-held or backpack sprayers are also a good choice for isolated plots back in the woods or in rough areas where you can’t get an ATV or tractor to. Set the nozzle on a wide spray setting and you can cover a small plot by hand in a short time, or spray selectively if weeds aren’t widespread. This system is also a good choice in early spring and late fall when the ground is wet and using an ATV or tractor would tear up your land.

6. Weeding By Hand

While hand spraying is good exercise, if you really want a workout this is where you’ll get one! You can use weed-digging tools or simply don thick leather gloves, grab the base of the plant close to the ground, and pull steadily. 

Of course if you manage a large acreage, this is not a practical approach. But for the small property landowner with isolated weeds in his plots, hand pulling is one more weapon to have in your arsenal for the war against weeds. Sometimes even with a hand-held sprayer you end up getting herbicide on quite a few adjacent clover or alfalfa plants accidentally if you’re targeting weeds such as thistle and pigweed that can intertwine with your crop. By using this old-fashioned weeding method you can avoid this peripheral kill with glyphosate. Pulling weeds is a great way to get your kids to help you.
I’ve pulled my share this way, and every one I remove I know allows several clover or alfalfa plants to thrive in that space where the weed used to be. It’s a satisfying feeling. Just go easy so you don’t wrench your back or aggravate a disk!
Conclusion. With this six-prong weed attack you can win the war on weeds, or at least knock them back to the point where they’re not a problem. Your plots and the deer will be the main beneficiaries. There’s no question that weed-free plots offer higher quality forage that tastes better and attracts more wildlife. 
And if that wasn’t enough, you’ll also have the aesthetic reward of looking at gorgeous green, weed-free plots shimmering in the sunlight.

That’s a sight I’ll never get tired of looking at!

Two Additional Ways To Win The Weed War

This six-prong attack is how I battle my weed problem, but there are other ways you can cut down on competition from unwanted plants in your food plots. For starters, avoid buying cheap generic seeds. When you think of all the money you spend on hunting and managing your land for wildlife, seeds are a small percentage of that. By purchasing the best seeds possible, you’ll get the strongest plants emerging, ones that have been proven over extensive testing to be fast growing with deep roots so they can out compete weeds when given a chance.
A second step you can take is to grow annuals in-between your perennial plantings. Planting brassicas or cereal grains in fall or soybeans and lablab in summer will go a long way towards eradicating weeds because these plants grow fast and aggressively, shading out the weed competition and robbing it of moisture and nutrients.
One study in the Midwest showed that a late summer radish planting can reduce weed biomass by two tons per acre over a field left fallow during winter. These plants also extract nitrogen, phosphorous and calcium from deep in the ground and deposit them at higher levels in the soil when they die, where clover and alfalfa plants can then make use of them. Annuals such as brassicas and rye also break up and aerate compacted soil, allowing the perennials to grow faster and out compete their weed competition.
So whether you’re just getting ready to convert a new site into a food plot or are throwing in the towel on an old perennial plot that’s gone downhill, consider planting an annual for at least one year. I guarantee you’ll have fewer weed problems by taking this simple step.

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