Things You'll Need
Disposable measuring cup
Disposable teaspoon (optional)
Unsulfured blackstrap molasses (optional)
Gentle dish detergent or baby soap (optional)
Nylon, knee-high stocking or kitchen flour sifter
Weeds detract from a lawn and garden's beauty, but sometimes chemicals that dispatch weeds prove more daunting than the weeds. So some gardeners want an effective, home-remedy alternative for weed control. Common baking soda, which is sodium bicarbonate, works as an herbicide on actively growing weeds. Baking soda acts as a desiccant, drawing water out of plant cells, which dries out the foliage. This same process happens when winter road salts injure landscape plants. Damaged severely, weakened plants die. Using baking soda requires its proper application and a diligent follow-up to eliminate weeds.
Fill a small sprayer with 2 cups of water. Use a sprayer that will allow you to target its water spray precisely enough so grasses and other plants surrounding weeds will stay dry.
Add surfactant to the water in the sprayer if desired. Water works alone, but adding surfactant improves results because it helps the water stick to weeds. Ready-to-use surfactants are available, or make your own surfactant by mixing 1 teaspoon of unsulfured blackstrap molasses and 2 teaspoons of either a gentle dish detergent or baby soap with the water in the sprayer.
Fill a nylon, knee-high stocking with baking soda. The stocking will leave a fine, even dusting of baking soda when it is shaken over targeted weeds. Alternatively, fill a kitchen flour sifter with baking soda.
Spray the weeds thoroughly with the water or water-surfactant solution, and immediately shake the nylon stocking's or flour sifter's baking soda on those weeds. Cover the weeds' leaf surfaces completely with the baking soda. Treated weeds should turn brown or black within a few days.
Repeat the process as necessary throughout the growing season. Baking soda works only on plant parts above ground, not on roots below the soil surface. Each application weakens the weeds and reduces the chance of them growing back, but follow-up treatments prevent weeds from recovering.
Baking soda treatments work best when done early in the day, which is when plant activity is high and plant pores are open. Temperatures above 85 degrees Fahrenheit help speed the treatments' results.
If non-weed plants are hit with a baking soda spray or dusting, they may be damaged.
- Nelson's Pest Control Inc.: Wanting to Kill Crabgrass "Do it Yourself"
- Environmental Pest and Lawn Services: Can Crabgrass Really Be Controlled in St. Augustine Grass?
- University of Florida IFAS Extension, Bay County: New Ways to Control Crabgrass in St Augustine Lawns
- Clemson Cooperative Extension: Control of Common Weeds
Jolene Hansen is a lifelong gardening enthusiast and former horticulture professional. She is passionate about reshaping the way people experience gardens and gardening. Hansen's work appears regularly in consumer and trade publications, as well as numerous internet gardening and lifestyle channels.