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  • Writer's pictureMatt Suprunowicz

How to Spray for Pests

Updated: Jul 31, 2023

How can we curtail pest populations?


This Lesson Plan is part the Gardening Module of SustainEd Farms' virtual programming.

Background: Spraying for pests

While living surroundings -- like trees, flowers, and beneficial insects -- are best viewed as helpful partners of the gardener or farmer, nature can also supply unhelpful guests: pests. Pests are insects or other animals that cause some sort of damage to a crop, which can be devastating to anyone that grows food as yields are stunted and plants die. Luckily, there are several ways to help control pests with various practices. Cultural pest controls encompass the practices employed by the farmer or gardener to indirectly deter the establishment of pest populations, such as rotating crops of the same family between different plots from year to year, which creates different environmental conditions that inhibit the continuous establishment of the same pests. Using barriers between the environment and crops, such as row cover, are forms of physical pest control. Biological controls, such as predatory insects, cause direct dieback of pests by killing off populations through natural ecological relationships. Finally, when growers are unable to control pests through the use of cultural, physical, and biological deterrents, many resort to chemical agents to stave off harmful insects. Though the use of pesticides can have negative downwind effects on the environment, there are some substances that can be used that have light or negligent effects on natural surroundings, such as using organic soap. In this lesson, we explore how to use a soapy water solution to keep pest populations in check.

Learning Objectives

Students will be able to...

  • Understand the categories and hierarchy of use of pest control methods

  • Employ the use of soapy-water to help combat common pests

Academic Vocabulary

foliar /ˈfōlēər/ adjective. - having to do with the leaves of a plant


1. Gather your materials. You will need the following supplies:

spray bottle · organic soap · water

2. Watch the following YouTube video to see a how-to demonstration. Then, follow along with the remainder of the lesson by reading the steps below.

3. The first step of controlling pests is identifying whether or not a certain insect is a pest. The clearest sign of a pest infestation is the appearance of holes in plant leaves. After finding plants with signs of damage, see if it is possible to identify any insect that is causing the damage. Ask yourself:

  1. What do they look like? Do you recognize this insect to be a pest, or a beneficial insect?

  2. Do they seem to be causing damage by eating the plant, or are they eating other insects?

  3. Are they on the leaves, the fruits, or on the branches or stem of the plant?

If it is clear that this insect is a pest that is causing damage to your plants, consider using pest control methods. If cultural, physical, and biological controls have already been exhausted, consider using soapy water as a chemical control, and follow along below.

4. Fill a spray bottle (standard is 1 quart) with 1 - 2 tablespoons of organic soap and water. Shake the bottle to mix.

5. Apply the soapy water mixture as a foliar spray, targeting leaves that are inhabited by the pest. Use as many sprays as needed in order to cover the infected area of the plant. The soap mixture will help break down the waxy outer body coating of the unwanted pest. If applied early enough, you can halt the growth of pest populations, and save your plants!

Additional Resources:

Download the PDF version of this lesson plan:

How to Spray for Pests
Download PDF • 1.60MB

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