Anyone that has tried growing a vegetable garden, food forest, or even just some herbs in their backyard has found that (especially here in South Florida) there are a number of pests to be dealt with. Some are sap-suckers that will posse up on the underside of leaves and drain the life from plants, some insects will spread diseases and fungus, and then there are caterpillars who can mow an entire tomato plant down in an afternoon. Since the point of growing your own food at home is to keep everything organic and healthy, how do we deal with these pests?
What does “Organic Pest Control” mean?
“Organic” in terms of pest control simply means that the methods you use are comprised of either physical control, plant derived chemicals, or predatory insects. There are a wide range of techniques- some are more broad-spectrum, and some only effect a certain bug in a certain scenario. It can benefit you to become aware of a handful of them so you can decide what will work best for your situation. Let’s start with the most basic.
1. Squishing them with your fingers
Yes, it can be gross. Especially when you’re dealing with mature, full size caterpillars. However, this technique can be surprisingly effective. It is best applied before a full on infestation takes place. Sometimes, you can find caterpillar eggs on leaves before they hatch, and just squish them between the leaves. Young caterpillars are pretty much the same, although sometimes hard to find. If a leaf is curled over itself or stuck to another leaf, you will be likely to find a caterpillar inside. Squish it.
As you may have guessed, this technique is best for caterpillars, although it can be effective for aphids or whiteflies as well, provided they haven’t already multiplied out of control. And, there is something to be said for leaving the goo of a squished insect on the leaf you found it on. Pests don’t like to lay eggs and multiply on the decaying bodies of their ancestors.
Sometimes you will find other pests, like scale or leaf miners, that appear stationary. For scale, you can just pick/flick them off of the plant in question. Leaf miners can be squished inside the leaves they are mining (they are at the wider end of the “trail” they have made).
2. Homemade sprays
There are dozens of recipes online for organic pest/disease control sprays that you can make in your kitchen, using ingredients you probably have on hand already. The most basic would be a spray bottle full of water, a bit of castile soap and a couple drops of vegetable oil (the soap deters the bugs, and the oil helps to emulsify the mixture so it spreads on plant leaves easier). You may have heard of this as a cure for aphids, but it can be effective for several types of pests. Other ingredients for a homemade spray can include baking soda, garlic cloves, hot peppers, vinegar, lemon juice, and various other plant materials. Here’s a recipe I’ve used, and can vouch for it’s effectiveness on aphids:
- 4 garlic cloves
- 2-3 cayenne peppers
- 2 tsp mineral/vegetable oil
- 2 tsp castile soap
- enough water to fill the rest of your spray bottle
Combine ingredients and blend, then let sit overnight. The garlic and peppers will become more potent if you wait. Then strain the mixture and pour into your spray bottle. This can be sprayed directly on aphids or whiteflies and other pests. Just make sure you don’t touch your eyes with hot pepper juice on your fingers… that would be painful.
Another homemade spray worth mentioning for plant care is a baking soda solution. Not for pest control, but this can help with controlling powdery mildew and other fungal issues, particularly on squash, melons or cucumbers. Just mix a few spoonfuls of baking soda with water and a couple drops of oil, and spray directly on the leaves.
3. Neem Oil
Some people are rolling their eyes. Neem oil works, I promise! Well it kind of works. It definitely works… somewhat. The issue is, it doesn’t kill any pests (good news if you are a militant pacifist vegan), and does not last very long. It takes multiple applications. And it has to be sprayed in the evening since it can burn plant leaves if applied in full sunlight.
Here are the benefits: It’s organic. It is very easy to find. It doesn’t matter if you use slightly too much or too little, it won’t harm the plant. It smells good (just me?). You can even get a Neem tree for yourself and blend the leaves with water, to make it for free.
It doesn’t work for everything, but I use it almost exclusively for whiteflies. I will put a spoonful or two of Neem oil into my gallon sprayer, fill with water, and go out at night with my headlamp and soak the undersides of my seedlings’ leaves. It definitely keeps whiteflies away, but is short-lived. I usually do this two or three nights in a row to get the best effect. The other benefit is that it is anti-fungal, and the problem with whiteflies is that they tend to spread fungal disease on the plants that they feed on. So I consider this the most useful application of Neem. In fact, it has been praised as a skin care ingredient for the same reasons – anti-fungal and anti-bacterial. So don’t knock it completely.
4. Bt (Bacillus thuringiensis)
Bt is becoming more and more popular in organic gardening and farming. It is a strain of bacteria which is safe to apply to plant leaves, and is very effective against caterpillar-type pests. It has no effect on birds, worms, or other beneficial insects.
The way it works: You spray a Bt solution (usually 2-3 tsp per gallon, read the label) on the leaves of your plants. Moths lay eggs on plants, caterpillars hatch shortly after. Caterpillars start eating leaves, and ingesting the bacteria you sprayed. The Bt produces a chemical effect in their stomachs, which essentially blocks the process of digestion, causing the caterpillar to die from starvation. This can take place within a few hours. It can be sprayed as a preventative measure, or applied once you notice caterpillar activity. Although, if you already have a large infestation, you might as well start with tip number 1 (Squish them).
5. Companion planting
Here is a method that is the subject of much debate, simply because it’s so broad, and can be influenced by many other factors. Still, some specific benefits have been documented and it can’t hurt to try.
In general, planting polycultures is an effective pest management strategy, simply because a wider variety of plants in the same space can be confusing for pests looking for something to eat. Most of us have heard that planting marigolds can deter nematodes, because nematodes don’t like the exudates produced by marigold roots. We’ve also been told that planting basil next to tomatoes can protect the tomatoes from pests, and improve their flavor. There are plenty of things that people swear by in this realm, but I’ll go over a few common (and proved) plant companionships.
- Basil (and herbs in general) planted throughout veggie beds. The aroma and volatile oils emitted by certain herbs can be effective in keeping pests at bay. Plus, you can never have enough basil.
- Borage is an herb that produces edible blue flowers, and is said to repel tomato hornworm and cabbage moths.
- Catnip can help with squash bugs and aphids,if planted beside plants that are likely to have problems with them. You can dry the leaves and make a tea which relaxes the stomach, or spray the tea on plants for pest control. Or, give it to your cat.
- Carrots are said to be effective at repelling most pests in the veggie garden, and are easy enough to plant in small rows in between other crops. The same is said to be true with other plants in the carrot family, which includes celery and parsley.
- Lemongrass seems to be an effective all around pest deterant.
- Onions (and other alliums) are also easy to inter-plant, and can keep pests away from brassicas, tomatoes, strawberries, cucumbers, etc.
- Sunflowers are obviously a great addition to any garden, but they are also a great trap crop for aphids. Most other flowers will work well too, as they attract beneficial/predatory insects, which will balance out the pest population.
If this is too complicated, here’s the gist of it: Plant a bunch of different stuff next to each other, it will help repel and confuse the bad bugs.
6. Beneficial insects
What eats the bugs that eat your plants? Beneficial insects do. There are many predator/prey relationships to speak of… If you do nothing at all to respond to a pest infestation, eventually something will come and eat those pests after they have multiplied to a point where it’s a free buffet for their natural predator. Most of us would prefer to act sooner in order to preserve our crops, so here are a few predatory insects that you can encourage, or purchase and release in your garden.
- Ladybugs will eat aphids if they can find them. You should always be pleasantly surprised to see ladybugs on the leaves of your plants, as they are likely to be eating aphids or other mites. They are also pretty.
- Assassin bugs live up to their name, and will “take care” of caterpillars, beetles, leafhoppers, aphids, and other bugs. They insert their proboscis into their prey, injecting a lethal saliva which liquefies the insides of said prey, which are then sucked out. Brutal!
- Predatory wasps are very unlikely to sting you, and most are very small. There are hundreds of species, most commonly used in agriculture is the Trichogramma wasp. They help by laying their eggs on most caterpillar and worm-type pests, then when the eggs hatch, the larvae immediately start feeding on the caterpillar from the inside out. Then, when the wasps are mature, they feed on nectar and help pollinate your plants!
- Green Lacewings are another great predatory insect, sometimes known as “aphid lions”. As that nickname suggests, they love to eat aphids and will also prey on other soft-bodied insects such as thrips, mealybugs, whiteflies and small caterpillars. They can consume hundreds of pest insects per week.
There are many other methods of controlling pests organically, but these are the ones that I see as being most accessible for the home gardener and urban farmer alike. You can try any of these methods easily and quickly, and see if they work for you. Best of all, they ensure that your home-grown goodness is kept clean from systemic pesticides, poisonous chemicals, and other nasty stuff that we try to avoid as organic growers. I hope that this was useful, and showed you pests can easily be controlled with organic methods. If you have experience with any of these methods, or have another that you’d like to share, let us know in the comments!
One other thing to note, is that in the case of a plant nursery where you are growing a lot of seedlings, cuttings, or otherwise tender plants, having them on a raised platform can help. It will deter pests, and promote airflow and drainage for overall healthier plant growth. Check out another of my blog posts for instructions on How to Build a DIY Bench for your Backyard Nursery.