An old friend was lamenting the loss of his chard crop to caterpillars a couple of weeks ago on Facebook. The temptation in these cases is to reach for toxic sprays: your local garden center probably has a wide selection of them. Of course, the toxins in these sprays won’t just kill the bugs eating your vegetables: they’ll also kill insects and microbial life forms you do want (not to mention the potential for making your family, your pets, and you sick). They’re generally a short-term solution… at best.
Nature, however, has been keeping pests in check for a lot longer than any garden spray… and doing a pretty good job in the process. While natural methods for controlling garden insects take some forethought and planning, you’ll end up with fruits and vegetables that you won’t have to worry about feeding to your friends and family… and garden areas you won’t mind the pets rooting around in.
Method 1: Healthy Soil & Healthy Plants
Healthy plants generally won’t need much external insect control: they’ve evolved to do the job themselves. In order to make sure you have healthy plants, you want to make sure they’re getting the nutrients they need… and that means healthy soil. It’s hard to beat regular additions of organic matter – compost and mulch – on this front. You’ll also want to pull weak plants so they’re not attracting pests.
Method 2: Companion planting
Once you’ve got that soil working hard, consider experimenting with companion planting as a method for incorporating natural insect control into your garden. This is a pretty simple concept: put plants together that create mutually beneficial relationships (and avoid putting plants together that can weaken each other).
From my own experiments with companion planting, I can attest to marigolds and borage as “super companions” – they support just about any other plant. But to make sure you’re taking full advantage of the many beneficial relationships available for your garden, check out this monster chart on Wikipedia.
Method 3: Beneficial insects
Beneficial insects are natural predators for the bugs you want out of your garden. So, my friend with the caterpillar problem probably wants Brachonids,Chalcids and Ichneumon Wasps (and can attract them with plants such as carrots, celery, parsley, caraway and Queen Anne’s lace (when they’re flowering – that’s what attracts the bugs). Ladybugs are great for aphids, and you can attract them with daisies, or actually buy them. For a full list of beneficial insects, including the plants you need to attract them, check out this list at eartheasy.
Method 4: Homemade Remedies
My grandmother used to place pie pans in her garden (buried to ground level), and fill them with beer – she swore this was a great trap for slugs. Lots and lots of other “recipes” out there for controlling insects, and they’re generally non-toxic (or, at least, not toxic enough to do you, your pets, or your plants any harm).
Lots of these recipes out there, but Marie Iannotti’s crowdsourced collection at About.com looks really thorough.
Method 5: Low/no-toxin products
The methods above are cheap and easy, but sometimes you still want something pre-made and readily available. That’s fine – just keep in mind that labels like “organic” and “natural” mean nothing: you have to know what’s in the product you’re buying, and whether those ingredients are things you really want in your garden.
Kind of takes the ease out of it, doesn’t it? Not to fear: Mother Earth News has created a specialized search tool that limits itself to sites and vendors they’ve selected. Just type in the problem you’re having (or the product you want, if you know what it is).
I’ve just hit the highlights here: feel free to share your own knowledge and experience.