The proper way to use sprayers

Spraying is the basis of all biological treatments against insects and parasitic diseases, and it can also be used for weed control. Sprayers make it possible to apply the preparation of a treatment (concentrated product diluted in water) as a light mist on undesirable plants or grasses.   

Before use, these four simple steps should be followed:

  1. Spot the problem you have noted in your garden.
  2. Identify the type of product that you need.
  3. Find the most suitable product following the advice of the salesperson in the relevant section of your garden shop.
  4. Apply it, following the product’s instructions for use and the specialist’s recommendations. 

Calculate the required quantity of water 

Calculating this according to a given surface area allows you to use the product sparingly but more efficiently, and it prevents you from having to manage effluent (liquid waste pollutant).
Calibrate the sprayer to calculate the amount of product used and the area treated in one minute.

The quantity of water to the used is calculated as follows

Quantity of water (in L) = Capacity of the sprayer - Quantity of water remaining in the tank after spraying until reaching beaded droplet form
For example, if you have two litres left, you should prepare 5L - 2L = 3L of solution (taking into account the product dosage indicated by the manufacturer for this amount of 3 litres of water).
If the dose indicated by the manufacturer is 15ml per 5 litres of water, you should add 9ml of product into 3 litres of water.
This is the "rule of 3”: (15 x 3) / 5 = 9 ml per 3L of water.

Spraying correctly: 

Spray until you get a "hanging drop", or a drop that beads at the end of the leaf without falling.

  • Put a defined amount of clean water into the sprayer (for example: 5L)
  • Spray the plants until a drop forms at the end of the leaves.
  • Empty the rest of the tank into a graduated pitcher.

Take the weather conditions into account:  

  • Sun: strong sunshine can affect a treatment product’s efficacy. For products that work through contact, 15 days of strong sunshine leads to these products being destroyed.
  • Rain: rain leaches out certain products. So-called “systemic” products must be applied when there is no risk of rain falling with the six hours following their application. If this is not the case, leaching of the product occurs, and it must be reapplied. Treatment products with a contact mode of action are rapidly leached out by rain as they don’t have the time they need to penetrate the plant. You need to therefore pay attention to the weather conditions on the day of application.
  • Wind: do not attempt to apply treatment products in strong wind. Take note, it is officially prohibited to apply treatment products when wind speeds exceed 19km/h. For gardeners who don't have an anemometer, the movement of the branches gives a good indication. This prevents unintentional damage that is regulated by a French Law of September 2006. For example: the dispersion of a product (of the weed control type) that can damage plants (vegetable gardens, etc.) in your neighbourhood and lead to legal conflict with your neighbours.

*That penetrates the plant through the leaves and then circulates within the plan by its sap. In the case of an insecticide, the entire plant then becomes toxic to insects.

Knowing how to protect yourself

When preparing or applying a treatment, put on gloves, impermeable clothing and glasses to avoid contact with the eyes and the skin. Do not drink, eat or smoke during application of the treatment.

Remember to store toxic products out of the reach of children and animals, in a locked, ventilated storage place. Protect them from heat, moisture and frost, on inflammable, non-absorbent shelves.

Finally, do not drain rinsing water and expired products down a sink, drain, watercourse or on a lot. Get information from your municipality as to where you should dispose of these.

Remember to also protect your cladding, walls, etc., when applying the product through a sprayer.