Neem oil is a vegetable oil that has a number of positive effects on gardens and lawns. The oil acts as a pesticide and fungicide and carries no ill effects for people or pets. The oil comes from the seed of the meliaceae tree, once native to India but currently grown around the world in warm climates. The fruit is similar to an olive and the seeds are cold-pressed; the resulting oil is bottled and has many uses outdoors and in cosmetics. Neem effectively interrupts the reproductive cycle of aphids, Japanese beetles and meal worms.
Mix the neem oil in a lawn sprayer at the rate of one ounce per gallon of water. One ounce is equal to one tablespoon. Shake the container to evenly distribute the oil.
Push on the tank's plunger to increase the air pressure in the tank in order to get a fine spray of the solution inside the tank.
Start at one corner of the lawn and squeeze on the pump's trigger to broadcast the neem solution on the grass by moving the nozzle sideways. You will have to continue to pump the plunger as you lose pressure in the pump. Work in straight lines to apply the neem solution over the entire lawn, noting mentally the width of your sweeps across the lawn to avoid spraying an area twice.
Empty the spray canister when finished and rinse it out with clean water before storing it.
Repeat the treatment of your lawn after a week to control the unwanted insects or help the soil heal from any fungus that may remain.