When preparing chemical sprays for gardens or fields, measuring the correct amount of every ingredient is important. Adjuvants are compounds added to a spray solution to enhance the performance of pesticides or fertilizers. A “spreader sticker” is a specific type of adjuvant designed to improve the physical characteristics of the spray on the plant surface. Its purpose is to ensure the active chemical covers the target area uniformly and adheres securely, directly impacting the application’s effectiveness and plant safety.
The Role of Spreader Stickers in Spray Solutions
Spreader stickers function through a dual mechanism that modifies the physical behavior of the spray solution. The “spreader” component, often a surfactant, works by lowering the surface tension of the water droplets. This reduction prevents the spray from forming isolated beads and allows the solution to flatten out, achieving better coverage across uneven or hairy leaf surfaces. The “sticker” component is typically a polymer or resin that acts as an adhesive to bind the chemical to the treated surface. This adhesive quality significantly increases the mixture’s rain-fastness, meaning the active ingredient is less likely to wash off when subjected to rain or overhead irrigation shortly after application, which is beneficial for plants with naturally waxy cuticles.
Determining the Correct Amount Per Gallon
The most accurate source for determining the application rate of a spreader sticker is the specific product label provided by the manufacturer. These labels detail the precise amount required to effectively modify the spray solution without causing harm to the plant. Typical recommendations often fall within a general range of 1 to 4 teaspoons (approximately 5 to 20 milliliters) of product per gallon of finished spray solution.
Many commercial labels express the required dosage as a percentage of the total spray volume, known as a volume-per-volume (v/v) concentration. For example, a label might recommend a concentration of 0.125% v/v when used with an herbicide. To convert this percentage into a measurable volume for a one-gallon batch, one must calculate 0.125% of 128 fluid ounces (the volume of one US gallon).
A 0.125% v/v concentration in a one-gallon batch equates to approximately 0.16 fluid ounces, or about 4.7 milliliters. Since 5 milliliters is equivalent to one teaspoon, this particular rate translates to just under one teaspoon per gallon. Following the label’s precise rate is necessary because the chemical properties of different sticker products can vary widely, necessitating different concentrations to achieve the desired surface tension reduction and adhesion. Using the wrong concentration can either render the main chemical ineffective or damage the plant.
Variables That Require Dosage Adjustment
While manufacturer recommendations provide a standard starting point, several variables necessitate adjusting the spreader sticker dosage.
Chemical Type
The type of chemical being applied is a primary factor. Some highly soluble or oil-based pesticides already possess inherent spreading qualities and require a lower adjuvant rate. Conversely, certain water-soluble chemicals or wettable powders might require a slightly higher dose to ensure they remain suspended and adhered.
Target Surface
The nature of the target surface significantly influences the required dosage. Plants like cabbage, onions, or those in the Brassica family possess thick, highly waxy cuticles that cause water to bead up easily, often necessitating the higher end of the recommended rate range. Plants with less waxy, rough, or hairy leaves generally require lower concentrations, as their surface naturally provides better mechanical retention for the spray solution.
Environmental Conditions
Environmental conditions also play a role. If light rain or heavy dew is anticipated shortly after application, increasing the sticker component slightly within the label’s range can bolster rain-fastness. However, exceeding the maximum label rate is risky and can lead to “over-adjuvation.” Too much surfactant action can cause the spray to run off the leaf surface entirely or facilitate excessive uptake leading to phytotoxicity, which manifests as chemical burns on the foliage.
Mixing Spreader Sticker Solutions Safely
Proper sequencing when preparing a spray tank is important to ensure all components mix correctly and remain functional.
The mixing process should follow these steps:
- Fill the spray tank approximately half to three-quarters full with clean water.
- Add the main chemical (liquid concentrate, soluble powder, or emulsifiable concentrate) while the tank is actively being agitated. Agitation prevents clumping or settling of the active ingredient.
- Add the spreader sticker, or any other adjuvant, last. Adding the sticker last prevents excessive foaming that can occur if the surfactant is introduced to water first.
- Incorporate the remaining water to reach the final desired volume, and ensure the solution is fully mixed before spraying begins.
When handling concentrated adjuvants, safety precautions must always be observed. Wearing personal protective equipment (PPE), such as chemical-resistant gloves and protective eyewear, prevents skin and eye contact with the concentrated product. Accurately measuring the small volumes required, often with calibrated syringes or measuring spoons, also prevents accidental over-application and potential chemical exposure.