One of the most common questions made by growers is how to apply pesticides to plants. In this chapter we will discuss how is the best way, what time is best to spray the plants, dosage and recommendations on certain products useful to spray on marijuana plants. If you have questions about pests, you should read this article about good practice applying pesticides
What is a phytosanitary product?
Phytosanitary means those products dedicated to combat and eliminate pests. There are phytosanitary chemical origin, and products with organic origin. Among the various baiting, we can find, are usually usual two concepts: "Systemic" and "By contact".
Systemic Means a product that, when sprayed, will penetrate the plant (and persist on it for a certain time).
On the contrary, it is understood as a product "by contact" anyone that does not enter the plant and acts only by contact with the pest. In this type of product is re-treatment needed since only individuals who were present at the time of spraying will be affected.
What should I consider to spray marijuana?
Marijuana, like most of the plants, can absorb nutrients and pesticides on its leaves. This ability is helpful, especially in crops affected by pests (red spider, thrips, insects, fungi, whiteflies, ...) or some nutrient deficiencies.
The first thing to know is the dose recommended by the manufacturer for product application. Most pesticides are water soluble and easily applied.
If the manufacturer offers a working range act as follows:
In case of strong pest: Maximum dose repeating application every five days to eliminate pests.
If symptoms of pest without serious evidence: Medium dose of product and Repeat application every 7 days to remove plague.
Neither more nor less than the labeled dose by the manufacturer. A very high dose could kill the plants (or negatively affect them), while a low dose may be useless.
Things you should know before spraying pesticides
Although some pesticides have organic origin, it is important to be careful using them. Be careful never goes wrong: plastic gloves, use long sleeves, or take show after product application costs nothing and can save trouble.
The anti pests are usually quite specific against a particular species. As a preventive measure, we can use a "triple action" but once a pest better use a specific product.
* Please note: Some products used to control pests are bacteria (one of the clearest examples is the bacillus thuringiensis, famous for being a great remedy against caterpillar pests in biological flowering). If the water in your area contains much Chlorine is better not to use it to spray. Chlorine is a known disinfectant of water (very popular in pools) that kills bacteria (beneficial or not) from water. Remember: Use chlorine water to spray is like spraying plain water.
How to spray marijuana plants
Most insects and parasites of cannabis coexist in the lower leaf (is the warmest area for life, and eggs). Knowing the situation, growers should spray marijuana plants from the bottom up. This secures acting more direct on the pests, besides better assimilation by the plant.
In outdoor crops with large plants, it is important to spray the entire plant consciousness to leave no unprotected area.
Important: Both inside and outside is preferable to apply plant protection products early in the day or late in the day. The light on the wet leaves could generate a magnifying effect (burning them).