Weeds are a common problem for any gardener. The problem with weeds is that they create competition. Competition for nutrients, water, and most importantly sunlight. They can also serve as a host plant for pests and diseases that you don’t want in your garden. There a couple of different ways that weeds can be classified, and these impact how we want to treat them.
Weeds are classified as annual or perennial. Annual weeds only live for a single season. Perennial weeds live for two or more seasons. The goal of an annual plant is to produce as many seeds as it can in a season to ensure the survival of its progeny next year. Perennial plants are looking to store energy in their root system so that they can make it through the winter. If you can keep annual weeds from putting on seeds by mowing or tilling them, you will reduce the population that you’ll have next season. Perennial weeds can be treated in the fall with a systemic herbicide. In the fall, perennial weeds are moving energy into their roots for storage. Therefore, that herbicide is moved into the root system and kills the plant at the roots. Crabgrass is an example of an annual and broadleaf plantain is an example of a perennial.
Broadleaf and grasses is another way of categorizing weeds. There are many herbicides that are effective on broadleaf weeds, like 2,4-D, but don’t work on grasses. Therefore, understanding what type of weed you’re dealing with is very important.
Mulch is a great way to suppress weeds. Many different materials can be used. Straw, wood chips, and sawdust are all effective. Mulch blocks the sunlight from hitting the soil and creates a physical barrier that weeds have to grow through, making it difficult for them to germinate and grow. You can also use weed fabric barriers. They do much of the same thing. However, because water can’t penetrate fabric barriers you’ll probably need to install some drip irrigation underneath the barrier. You can also inject fertilizers through the drip irrigation using an injector.
You can find any number of recipes online for natural herbicides. Some of these are effective, others are not. Unlike some synthetic herbicides, these are not selective. They will kill every plant they touch. One problem is that they only kill the part of the plant that they touch. Therefore, if you have a perennial weed you are going to have to re-treat that weed many times before its root energy reserves are depleted and it stops regrowing. Vinegar is a common ingredient in these mixtures. I’ve seen recipes with citrus oil and soaps too. One issue with using these is that if you use them too much, they’ll damage your soil. Recipes with citrus oil are really more of a biocide, meaning they’ll kill plants, insects, earthworms, or anything else it meets. That’s not to say don’t use them, but rather use them judiciously. A natural product designed to kill is dangerous to the environment when it’s not used responsibly.
Shallow tillage is a great way to control weeds in row middles. Or, making your rows wide enough so that you can fit between them with a lawnmower allows you to remove weeds. Hand hoeing is hard work but very effective. I find that holding the hoe at a high angle and using the corner of the blade allows me to get just under the crown of the weed and pull it out. It also helps save your back.
If you have questions about weeds contact your county Extension Office or email me at Jacob.Williams@uga.edu.