Two of the most common herbicides for home use are glyphosate and 2,4-D. Glyphosate, which was under patent by Monsanto, is more commonly referred to as Round-Up, but now that it is no longer under patent it can be found under many trade names, including Honcho, Kleenup, Killzall, Eliminator, and Enforcer.* Glyphosate is marketed as a non-selective herbicide, meaning it will kill any plants it comes into contact with, but it is most effective on the grasses. Many difficult-to-kill weeds are not significantly affected by low concentrations of glyphosate.

Glyphosate is rapidly neutralized upon contact with soil. For this reason, it is often considered one of the safest products to use for weed control, as the area can be planted again immediately. It must come into direct contact with green, actively growing plant tissue, after which it moves or translocates through the plant into the roots. Plant roots do not take it up from the soil. When mixing glyphosate, don't use ditch water, as the chemical will attach to the soil particles and become largely ineffective.

2,4-D is a broad-leaf herbicide, often recommended for use in established lawns to control such common weeds as dandelion, plantain, and the mustards. It should not be used on newly established lawns, until after the third mowing. It is found in many products and under many brands. It is not effective on the weedy grasses. Like glyphosate, it is taken up by green, actively growing material and translocates through the plant. A characteristic turning and twisting of the plant material indicates its activity.

2,4-D can be found in three formulations: amine, which is a salt, ester, which is in an alcohol carrier, and low-vol (low volatility) ester. The low-vol ester will volatilize at 85 degrees F. and the regular ester at even lower temperatures, moving the chemical into the air and spreading it to non-target plants. 2,4-D in the ester formulation has been shown to travel distances of well over a mile, harming sensitive crops along the way. The amine formulation is the safest to use and is recommended for home use. Plants differ in their sensitivity to 2,4-D; tomatoes and grapes are among the most sensitive. As always, avoid spraying on a windy day.

Unlike glyphosate, 2,4-D is residual in the soil for up to four weeks. Wait at least that long before planting in the treated area.

To control difficult weeds that 2,4-D alone can't manage, these two chemicals can be combined into a mix that will effectively take out both broadleaf and grassy weeds. Mix the recommended amount of both the glyphosate and the 2,4-D into the same gallon of water. Be careful with this mixture, as it will kill nearly any green plant it contacts. This mixture is more effective on bindweed and other tough weeds than either glyphosate or 2,4-D alone. Like the 2,4-D alone, it will remain in the soil for up to four weeks.

As with any chemical, be sure to read the label and follow the directions. It is important not to use an excessive amount of these herbicides in the mix, because this may burn back the tops of the weeds without allowing time for the chemicals to move through the plants into the roots. Use only the recommended amounts of each chemical.