Gardening Q & A: Spring Pre-Emergent Weed Control

 

Spring Pre-Emergent Weed Control

Here are some of the questions we hear from our customers regarding Spring Pre-emergent Weed Control:

It is already February. How can I stop the weeds from coming up this year?  

Now is the time to apply a pre-emergent to the lawns. With these warm sunny days, weed seeds and weedy grasses will start to sprout.

What is a pre-emergent?

A pre-emergent is organic or chemical product that when applied to the lawn will help prevent seeds from sprouting. All kinds of seeds from grassy type to broadleaf weeds.

What is the organic pre-emergent called?

The organic pre-emergent is called Corn Gluten Meal. It comes in a powdered form called Corn Gluten Meal or in a granule form called Corn Gluten Meal Granules. Both work the same way in stopping seed from germinating. The meal will coat the ground solid, and the granules will leave some small areas uncovered. The meal is much harder to apply but will do a better job in controlling weeds and unwanted grasses. Granules are much easier to apply to the lawn and will do a very good job in controlling unwanted weeds and grasses.

How does it work?

When used at the right time and right application rate, corn gluten meal works like this. The naturally occurring proteins in corn gluten meal interfere with the ability of the newly sprouted roots to take up water, without which the plant dies before it can form more roots or leaves. Dr. Christians (of Iowa State University) and his researchers have tested twenty-two common weed species for susceptibility to corn gluten meal including Black Medic, Black Nightshade, Buckhorn Plantain, Catchweed, Bedstraw, Common Lambsquarter, Curly Dock, Dandelion, Purslane, Redroot Pigweed, Velvetleaf, Annual Bluegrass, Barnyard Grass, Creeping Bentgrass, Giant Foxtail, Large Crabgrass, Orchardgrass, Quackgrass, Shattercane, Smooth Crabgrass, Wooly Cupgrass, and Yellow Foxtail. They found that corn gluten meal significantly reduced plant survival, shoot length, and root development of all tested species.

How much area will corn gluten meal cover?

Use at the rate of 20 lbs. per 1000 square feet. That means a 40-pound bag will cover about 2000 square feet.

What about the other pre-emergents on the market?

Those that are made from chemicals work the same way as Corn Gluten Meal. Chemical pre-emergents stop the seeds from germinating, and in some brands, the chemicals have a longer residual. Meaning they will last longer in the soil to control weed seed germination.

How much will chemical pre-emergents cover?

Chemical pre-emergents will cover much more square feet than Corn Gluten Meal. For example, a 35-pound bag of Hi-Yield Turf & Ornamental Weed & Grass Stopper with Dimension will cover 15,000 sq. ft. in the cool season and 10,000 sq. ft. in the warmer seasons.

I have weeds in the vegetable garden, so I can use a pre-emergent in the garden?

NO! Pre-emergents are not labeled for the vegetable gardens. A pre-emergent will stop the vegetable seeds from sprouting and all that hard work in planting seeds would be lost. Most if not all vegetable seeds would NOT germinate.

I plan on overseeding my lawn where I have dead patches but I want to use a pre-emergent to stop the weeds.

You can use a pre-emergent only on those areas that will not be over seeded. A pre-emergent will also stop the grass seeds from germinating. So do not treat areas planned for over seeding.

Would it be okay to fertilize and use a pre-emergent at the same time?

Yes! You can apply both on the same day and water both in together,  but I would not mix them in the same spreader. The reason is that each product has different size granules and the smaller size granule will work it’s way to the bottom of the spreader first. Meaning the smaller granule product will be applied first to the lawn and leaving the larger granules to be applied last. It would not be an even coverage of both products.

Will a pre-emergent hurt my trees?

NO! Any tree or shrub with a root system already growing will not be damaged.     NOTE: DO NOT use any type of Weed and Feed containing 2-4-D around trees or shrubs. This will do damage to the trees and shrubs

Can I use a pre-emergent in my flowerbeds?

Yes, but remember pre-emergents stop seeds from germinating.   If you are planning to plant flower seeds or have wildflowers or flower bulbs in the beds do not use pre-emergents in this area. If a plant already has a root system growing (like bedding plant) it should be safe to apply a pre-emergent to the beds after you have them planted.

With any product READ and FOLLOW ALL LABEL DIRECTIONS

Have more questions about Spring Pre-Emergent Weed Control products? Bring them to our experts at each of our eight Russell Feed & Supply locations or submit them to us here.