The Benefits of Using Peppermint Oil Spray in Your Vegetable Garden
Not all peppermint oil is the same. I only recommend using Mentha Piperita. This is what I sell on my website and use in my garden. It is a little more expensive but has the strongest scent. Wherever you choose to by your peppermint oil, make sure the label displays Mentha Piperita. You want the strongest scent. You can find the recipe I use at the end of this post.
Peppermint oil essentially does two main things to discourage insects from coming into your garden. It masks the scents of your vegetable plants and it is an irritant.
It makes for an extremely good repellent for very small insects like spider mites. You may have heard some oil sprays smother and kill soft bodied insects. That is true; however, peppermint oil is used for its scent. You would need to use a lot more oil to make a smothering oil insect spray. Cheaper unscented oils are better for that purpose.
Insects locate plants visually and by scent. That is why flowers are often scented and colored. Many of your pollinators will still easily find you garden even when you are using peppermint oil sprays.
When you pick vegetables, you break the plant. You may notice three distinct odors when you pick a cucumber, tomato or squash. Problematic insects also notice the scents. Pruning plants releases the same odor or pheromones. Your peppermint spray helps to mask this. Wind and heavy rain can also damage plant leaves just enough to release plant scents.
The key to the successful use of peppermint oil is spraying on a schedule. I recommend spraying every 5-7 days routinely as a masking scent. You can spray around the plants and on the soil. If you are using the spray for the first time, spray a few leaves of each plant variety and wait 48 hours for damage. Only cover an entire plant when you know your spray mix does no harm. This is good practice for any spray formula, you introduce into your garden.
If you are using it as a repellent and irritant for very small insects like spider mites, I recommend spraying every 3-5 days, making sure you get under the leaves.
From The Rusted Garden – Seed & Garden Shop:
Garden Care Kit: Peppermint Oil, Neem Oil, Rosemary Oil and Calcium Nitrate:
Garden Care Kit with Spray Bottles: Peppermint Oil, Neem Oil, Rosemary Oil and Calcium Nitrate:
2 Ounces (Dropper Bottle) of Peppermint Oil (Menta Piperita) for Insect Management:
The basic recipe I use is 1 drop of peppermint oil per 2 ounces of water. This is great for small batches. You can use 1/2 - 1 teaspoon of peppermint oil per gallon of water. Use just enough soap in your batches to help disperse the oil through the water when shaken. That is usually a couple drops of soap per quart or a teaspoon per gallon based on the soap you are using.
Shake your peppermint oil spray every few minutes when spraying your garden. Two ounces of oil is about 1200 drops according to conversion websites and it will make 12-24 gallons of spray based on using 1/2 or 1 teaspoon in a gallon of water. A mix batched of peppermint oil spray is good for about 1 week and probably longer. The oil itself has a shelf life of several years.
The key to effectively using peppermint spray and other scented sprays is to stick to a schedule. Schedules vary by Garden Zone as they all have their own insect issues. When in doubt, spray more often. You also want to start spraying several week before the problematic insects arrive to your gardens. The best way to learn this is by keeping a journal of problems in your garden, documenting the date they are first noticed.