How to Make Herbicides

You don't want potentially harmful chemical residues where your children and pets play or where you grow food (see References 4, page 1). Using natural products to care for your yard makes sense, but homemade herbicide recipes that include baking soda or salt alter the soil, hindering plant growth and making garden management difficult, according to specialists at Colorado State University Extension (see References 3). Manual removal is the safest way to get rid of weeds, but some simple, organic products can give you a leg up on these plant pests.

Pre-emergent Weed Control

Determine the growth stage of the weeds -- the best time to tackle them is early spring or early fall before they sprout. Corn gluten meal is a natural herbicide you can apply twice yearly for such pre-emergent weed control. (See References 1, pages 6 and 7)

Pour the corn gluten meal into the spreader, and apply at a rate of 12 to 20 pounds per 1,000 square feet, depending on the known weed cover. For small areas, like flower beds and gardens, simply rake the corn gluten meal directly into the soil. (See References 1, page 6)

Water the treated area thoroughly, but don't over-irrigate. Use a hose with a sprayer attachment to water small patches and hard-to-reach areas; sprinklers are good for large areas if they reach every square inch. (See References 1, page 7)

Allow the treated area to dry out thoroughly before resuming your regular irrigation schedule. Remember to turn off automatic sprinkler systems until the soil is dry. (See References 1, page 7)

Targeted Weed Killer

Pour household vinegar, 5 percent acetic acid, into a spray bottle and label the bottle clearly with a waterproof marker. Vinegar is non-toxic to people, but you still don't want to mistake it for something else.

Spray large clusters of weeds directly with the vinegar, but be aware that it will damage any vegetation it touches (see References 2). Use a plastic or cardboard shield to block the overspray from plants that you don't want damaged.

Dip a paintbrush directly into the spray bottle to apply the vinegar directly to small areas. This allows you to be sure where the vinegar is going.

Repeat applications three times for longer-term control (see References 2).

Tip

• Acetic acid-based herbicides from your local garden center contain a stronger concentration of acetic acid than household vinegar; when using these products, follow label directions. For long-term killing of perennial weeds, stronger is better. (See References 2 and 5)

Warning

• Don't use any vinegar stronger than 5 percent acetic acid for killing weeds unless it is registered for use as an herbicide and labeled accordingly (see References 5).