Non-Toxic Weed Killer and Fertilizer

Corn Gluten Meal

• Corn gluten meal -- a byproduct of corn syrup production -- makes an effective non-toxic preemergent weed killer. This means it can prevent weed seeds from germination, but won't kill existing growth. For lawns and turf, the Bio-Integral Resource Center suggests applying around 20 pounds per 1,000 square feet in early spring, then the same amount at the end of summer. Watering in after applying helps the meal break down into the soil. It doesn't work for all weeds, but many common turf weeds can be kept at bay with corn gluten meal.

Vinegar

• The acetic acid in vinegar can kill or stunt many common garden weeds. However, it only kills the top growth of the plant, meaning perennial weeds may grow back. Using home-grade vinegar is generally a safe and non-toxic option, though it has variable results. For small jobs, such as weeds in the gaps between paving stones, home grade vinegar may be enough. Vinegar with 10 to 20 percent acetic acid is much more effective, according to the University of Illinois Extension. However, at these high concentrations, vinegar can burn skin and eyes. Follow label directions as stringently as if you were using a chemical herbicide.

Manure

• Horse manure, as well as processed chicken and cow manure pellets, makes excellent non-toxic fertilizers. Manure is naturally rich in nitrogen, organic matter and important minerals, although exact amounts vary depending on the type. Well-rotted horse manure can be worked into freshly dug soil or plant beds. Cow or poultry pellets can be used to top-dress lawns or soil. Around 100 pounds per 1,000 square feet works best, according to an Iowa State University Horticulture Guide. You can apply it once in late summer or split it into two applications -- one in early spring and the other in early fall.

Blood, Bone and Cottonseed Meal

• Blood, bone, cottonseed and fish emulsion may sound unpleasant, but they make non-toxic fertilizer if used correctly. Blood meal is blood in powdered or pellet form. It has high nitrogen content, so while non-toxic, it can cause harm if used in large amounts. Fish emulsion makes a good nitrogen fertilizer booster in late spring for plants. Other examples include bone and cottonseed meal. When using any of these products, check the package to find out their nitrogen, phosphorus and potassium ratio, since ratios vary by manufacturer. For example, cottonseed meal typically has a ratio of 7-3-2.