The question of organic pest control is first on everyone’s mind when considering an organic garden. Whether you are new to gardening entirely or converting your conventional garden space into an organic one, your first concern is likely that you’ll be over-run with bugs. Fortunately, this concern has more to do with our general misunderstanding of bugs and organic gardening practices than with any real problem with going toxin-free in the garden.
Not All Bugs are Pests
The best thing you can do for your garden is to realize that not all bugs are pests, and learn to differentiate them. We’ll dig into some specifics in a minute, but for now let’s look at the principle of the thing: bugs congregate around growing things. Some like to eat plants, some like to eat other bugs, some move pollen around and actually make your plants grow, and some like to lay their eggs and let them do the dirty work. Knowing which bugs are there to help and which are there to harm is one of the first things an organic gardener should learn.
Once you have a handle on the bugs you’re dealing with, you can move on to either encouraging their presence or shooing them away. Not only do you learn that not all bugs are pests, but not all pests need to be eliminated. You may want to leave some around in order to trap predators, or you might just plant a trap-plant that allows them to feast while your real edibles and ornamentals thrive elsewhere.
Before you can control your pests, you have to be able to identify them.
Identifying Pests vs Beneficial Bugs
There are countless insects in the world, yet somehow we all seem to wind up with the same basic bugs in our gardens. Which is great, because it lets us compare notes, conduct studies, share folk wisdom, and employ researched tactics to minimize problems and enhance benefits for your garden.
By learning to identify some of the more common types of bugs, you can spot early appearances of pests before they become infestations, enjoy the presence of helper bugs, and cultivate your organic garden as a living organism.
Of course, this list won’t be extensive, but it’s a good start. When you don’t know what bugs you’re up against, you can always search the internet with a description of the bug to try to identify it.
- Aphids: A definite pest, aphids are tiny but vicious if left uncontrolled. They favor tomatoes and roses but can be found on the broccoli family, beans, and squash as well. Watch out for very small, usually green bugs in the early stages. They’ll gather in groups on your leaves and stems once they pick up in population. Ladybugs and lacewings love them, and soapy sprays can take care of concentrations of them, too.
- Beetles: Beetles are identified by their hard exoskeleton that is divided into two sections. They can range from smaller flea beetles that make a great snack for ladybugs to the giant Japanese beetle that must be trapped. Really, nearly any kind of beetle is bad news in the garden - cucumber beetles, bean beetles, flea beetles, Colorado potato beetles…Keep an eye out for beetles, and get ready to take action if they start to invade! Beetles will hide in your leaf litter overwinter, so be sure to clean everything up, and go for a cover crop instead of mulch if beetles have been an issue.
- Worms: Earthworms may be the soil’s best friend, but there are plenty of other worms that you don’t want hanging around. Cabbageworms, army worms, and hornworms come to mind as some that can be devastating. Tomato hornworms are some of the easiest pests to identify, big for your average garden pest with bright green coloring and red dramatic “horns.” Worms will typically go for the leaves, with a trail of holes left as evidence of their feasting.
- Borers: The bane of every cucurbit gardener’s existence, borers can destroy an entire crop in no time. They are tricky because you don’t necessarily see them on the surface like other bugs. Instead, you’ll see a small hole in the stem or vine with a sawdust-like debris around the edge of the hole. By that point, they are already in the plant and eating it from the inside out. Squash vine borers and corn borers are the biggest enemies. Keep plants off the ground, avoid breaking vines to give the bugs and entrance, and rotate crops with each planting.
- Leaf-eaters: Leafy greens are easy to grow, but they can still be taken down by slugs and leaf miners. Watch for the slimy trail of slugs. They’re easiest to catch in the morning when the ground is still dewy. Otherwise, you’ll most likely spot the damage that leaf eaters leave when your leaves are, well, eaten!
- Mites: Spider mites tend to show up where other pests aren’t typically a problem. Easy-growing beans, hardy sage and rosemary. Where other pests aren’t typically interested, spider mites will give them a try. The bigger problem is that mites can be incredibly difficult to detect. Until you’ve got enough to do damage – yellowing, webbing – you probably won’t even know they are there. Slightly bigger, teardrop shaped mites with longer legs could be predatory mites. Stick with inviting lacewings and ladybugs to your garden for the best mite control.
- Helpers: These are the bugs to keep around! Ladybugs and lacewings are at the top of the list, making meals of mites and aphids and smaller pests. Praying mantis and even some spiders can take care of bigger problems. Nematodes may be helpful for controlling squash bugs and other borers. The most interesting helper by far are parasitic wasps, which lay eggs on hornworms. If you see a hornworm with a strange white texture or attachment on its back, leave it alone! The wasps have done their work. The larvae will feed on the hornworm and soon it will be no more. Gruesome, effective, and kind of cool.
Organic Pest Control Options
The best way to grow an organic garden is to really cultivate it. Not just plant and harvest, but get in there and see what makes your space tick. Keep good notes in your garden journal and make adjustments from year to year. Pay attention to things like the weather and soil composition to see how your space has special quirks that need attention.
Organic pest control is most effective in this kind of environment – one where you’re looking for the best way to grow your plants and not just a new spray to get you through another season.
With that in mind, there are some levels of organic pest control that you can adapt to as needed.
Always your best ally, start here. Even if you already have an influx of pests, start employing prevention strategies to help mitigate the problem – even if you don’t see the results until next season. There are universal prevention strategies that will help cut back on both pests and disease. Crop rotation is a big deal, as is clearing out the beds and planting a cover crop during the winter. That’s because bugs like to stick around for an easy meal – hidden in heavy mulch or fallen plants, ready for the same crop to come back next year.
Row covers – like you might use for frost protection – early on can help keep bugs (and their eggs) off of your young sprouts, but be careful. If some sneak under the cover then you’ve basically given them food AND shelter!
Keeping mulch off of the stems, allowing airflow around and between plants, and keeping vines from falling over onto the ground can all help prevent pest infestation.
This is where companion planting comes in handy. Plant fragrant herbs like dill and cilantro in edges or at the corners to help bring in beneficial bugs. Flowers are also big helps in the garden – tansy brings in lacewing and ladybugs to eat aphids, and one study found a 60% reduction in cucumber beetle populations around tansies!
Where an infestation is present, you may be able to purchase predators like ladybugs or nematodes from a nursery. This is not a preventative measure – make sure you’ve got plenty of pests to feed them with! If you’re going for the backyard farm effect, you might consider some chickens or guineas to help peck away at pests.
It sounds inefficient, but really it can get the job done pretty easily. If you’re already spending 15 min or so in the garden every day, you can lift the leaves and check for pests. Pick them off and drop them in a bucket of soapy water. If you’re hoping for predator bugs to come to the garden, try to leave a few for them.
Traps of various sorts are helpful organic pest control measures. Sticky traps are usually designed using pheromones or attractive scents, intended to lure the pests to the trap. Another potential trapping method, especially for something like squash bugs, is to plant a decoy plant and let them have at it – then carefully remove the whole plant from the garden. You have to be careful with this. Don’t let it go so long that the bugs dig into the ground and settle in for next year or spread to another plant!
Slugs are usually trapped well, too, or picked off by hand after following their trail.
Organic pest control may not rely on alternative sprays, but that doesn’t mean it excludes them. Even something as simple as a soapy-water spray can suffocate bugs and control small populations. Spray treatments that are still organic may contain oils, pungent essential oils, soap, and more. Watch commercial ingredients carefully to be sure you still have a safe product. Or simply make your own with water, soap or oil, and peppermint or cedar essential oils.
Diatomaceous earth is another organic bug treatment that can be used, usually with good success. The powder basically digs into the bugs’ exoskeletons and suffocates them. Remember, with sprays and powders, you’re going to eliminate the good bugs with the bad. Use them extra carefully or as a last resort.
By viewing pest control as a way to optimize the garden, organic pest control becomes more about balance than elimination. Start with prevention of pest overgrowth and you’ll minimize both the work needed and the threat to your plants. Move on to other methods as necessary, keeping in mind that this list was not intended to be a hierarchy.
You may jump from prevention to a natural spray and back to hand-picking before summer ever hits. The important thing is to be flexible, with your ultimate goal being a beautiful garden – from ornamental haven to edible landscape and back again. Anyone can have a pest-minimal organic garden.