You Can Use Oil and Water For Organic Pest Control?

All oil sprays are classed as organic, even if some are made from petroleum oils. Basically they use something like a baby oil, with a detergent to act as an emulsifier so they can be mixed with water to spray. They coat the plant and slowly evaporate over a few days. In the case of "dormant oils", they actually can take up to a month to evaporate. Only use dormant oils in winter on the bark of trees and shrubs. 

Lighter weight and lower dosage (more about "dosage" in a bit) oil sprays are okay in warmer weather, but still best in the cool morning hours. 

Make Your Own

A simple home made oil spray can be made with any cooking oil, even used, ABF(already been fried) oil and a good mild dish detergent, like Dawn. Use 2-4 tablespoons of oil and 1/2 teaspoon of detergent per gallon of water. You can double the oil and detergent for a winter dormant spray. 

In hot weather, stay towards the lower end of the dosage. Pure water itself also works well, and I'll get to that in a bit.  IMPORTANT: Don't use the orange oils and solvent like oils, they are very hard to dose just right without killing the plant.

Where Oil Doesn't Work - Water Does

Oil sprays work great for the plants that can tolerate them, which happily, is most. Sadly tomatoes do not, and some of the worst bugs, like spidey mites, would succumb easily to the oils. For them, there's always good ole H2O. 

Water, blasted on plants just below the strength that will damage the plant, knocks off most troublesome bugs. In many ways, I don't even like organic bug killers, like oil sprays. Most sprays, even organic, will always do a better job of killing the good bugs than the bad bugs. Good bugs, predators, walk about all over the plant, hunting down the bad bugs. They are sure to walk into any poison or organic pesticide you put on the plant. 

Bad bugs, like thugs hiding in an alley, mostly hang out in nooks and crannies on the plant, sometimes creating them by injecting chemical that distort and curl the leaves. It is very difficult to get good enough coverage of your spray to get them all. Bad bugs have the advantage of reproductive fecundity; they multiply very rapidly, so they come back with a vengeance. Horny Bastards.

By using plain water, you knock off the bugs, which for most pest bugs, is nearly 100 percent fatal. They are wimps. Even the most active and tough bad bugs, like sharpshooters, still live life on the nutritional edge, and being chased around by water wreaks havoc in their lives. Predatory bugs are very active, tough and ambulatory. They can easily just get back to work. Good bugs also need drinks of water sometimes too. Using water to knock down a flushing bad bug population can give the predators enough time to get caught up and keep the problem under control. It help put things back in balance.

The only downside is that keeping plants wet is sometimes conducive to disease. So do the bug water sprays in mid day on dry (low humidity) sunny, breezy or hot days, when the plant will dry off pretty quickly.

A great tool for power misting to get the bugs is one of those water wands, that usually has the water breaker screwed on the end. A breaker is kind of like the nozzle with lots of holes to make the water rain out softly. Unscrew that breaker and put back on either one of those mister nozzles, or I like even better, just one of those cheap plastic water cut off ball valve thingies. You can set it to many levels of mist to harsh strong sprays, like for conifers, junipers, very tough plants, etc(that get spider mites in hot weather). The wand gives you an extension of your hand and the bend at the end lets you get up under the plants. Blasting up from below is the best way to knock off the bad bugs.

Taking care of your pest control problems organically - especially in vegetable gardens - keeps dangerous and unknown chemicals out of your bloodstream, and out of your family's. Our What's In Your Body story covers more of this.

Do you have any ideas on what's worked for you? Let me know in the comments below.