Sustainable Pest Control
As gardeners, we develop close relationships with our plants, especially those we start from seed! So we understand the distress of finding all your lettuce mowed down by snails, or your squash leaves dusted with mildew. It can feel like a personal attack and the impulse to retaliate is strong and swift. But before reaching for that quick fix pesticide, pause, breathe, and take a moment to consider the long term health of your garden.
It can be both empowering and a little frightening to recognize the impact our gardens have on the natural world. With increased urbanization and habitat loss, our gardens are no longer only a refuge for us, but for many species of wildlife. They are a patchwork ecosystem that feed and shelter birds, butterflies, reptiles, and even mammals. They can be mini carbon sinks, that help build precious top soil and contribute to the watershed. So the choices we make in our gardens really do have a broader effect on our communities.
Fortunately, there are so many ways to grow beautiful, productive gardens without pesticides. The first step − which may seem obvious but truly is the key − is to grow healthy plants. A vigorous, healthy plant is far less susceptible to pest predation and so less likely to require intervention. When starting from seed, it is important seek out fresh seed that is free from weed contamination and with high germination rates. If you’re using Lake Valley Seed, we check all those boxes!
Right plant, Right place
Next, carefully select your site. Let the motto “right plant, right place” be your guide and do your best: give sun loving flowers and veggies a site that gets 6-8 hours of sun a day, tuck those thirsty plants in beds that receive irrigation or have water retentive soil, and plant deep rooted vegetables where there is little root competition. Some plants will select their own favored site either by reseeding or spreading with underground stems. Whenever possible, leave these plants in their chosen spots to benefit from whatever they were seeking out.
The right plant for your garden may be one that has been passed down for many generations, or a favorite variety that always produces well. It’s helpful to note what does well and what struggles from year to year, then let those notes help your plant selection. If you can identify the pest or disease pressure in your garden, you can then seek out resistant varieties.
At Lake Valley Seed, we offer many varieties that are resistant to some of the most common plant ailments. If you’ve struggled with powdery mildew on your cucurbits or legumes, try the following resistant varieties:
Straight 8 Elite
Oregon Sugar Pod
Sugar Daddy Snap
Tomatoes are notorious hosts for pests and diseases. But gardeners’ love for tomatoes has been strong and enduring enough to develop many resistant varieties that thrive under pressure. Verticillium and Fusarium wilts (often notated as V and F on plant labels and seed packets) can quickly devastate a tomato crop. Resistant varieties we offer at Lake Valley Seed are: Better Boy, Ace 55, Celebration, Granny Smith, Lemon Boy and Super Sweet 100. Better Boy and Lemon Boy have the added protection of nematode resistance. If you’ve ever shared your garden with root-knot nematodes, you’ll know this is a real boon!
Selecting quality, disease-resistant plants and siting them in the best location are good preventative measures against pest problems. For additional protection, we turn to cultural practices that make your environment less hospitable to pests. It is likely you already implement some of these practices, such as cleaning your tools between uses and weeding before plants set seed. Others may be reserved for more serious efforts.
If weeds become insurmountable, or if you are expanding your garden space, rather than reaching for the herbicide and contaminating your soil, try sheet mulching the area by laying down cardboard or heavy paper and topping with compost and mulch. This method starves established weeds of light, and prevents new seeds from germinating. Bonus, stale cardboard is a magnet for earthworms who love to snack on it, providing free worm castings in return!
Soil dwelling pests like root-knot nematodes and certain viruses can be thwarted by practicing crop rotation. This simple method of planting different crops in different areas of the garden each year works by withdrawing the insects’ food source or the virus’ host, reducing their populations. It also allows for various soil nutrients to be available to different plants and for the soil to recover between heavy feeders. Try planting nitrogen-fixing plants like peas or beans following nightshades like tomatoes or peppers to replenish soil nitrogen.
This concept can be applied between seasons as well with cover cropping. Following the idea that nature abhors a vacuum, cover cropping works by covering bare soil with a desired species rather than exposing it to weeds, wind and runoff. Garden beds can be thickly sown with peas or oats after summer vegetables to replenish nitrogen, add organic matter and simply hold soil in place.
Growing plants with complementary attributes together, or companion planting, makes for a much more resilient garden. If you’ve ever grown a three sisters garden with corn, beans, and squash you can surely attest! The corn provides a trellis for the beans, who in turn fix nitrogen to feed the hungry corn plant, and the squash acts like a living mulch, suppressing weeds and shading the soil.
We can practice companion planting for pest control as well. French marigolds, like our Brocade, Lemon Drop and Petite mixed colors, deter nematodes so are a good choice to plant with nightshades and the amaranth family like beets and Swiss chard. Nasturtiums are very attractive to aphids and can be used to lure them away from your vegetable crops. For this technique, also known as trap cropping, you intentionally plant a sacrificial crop to protect a primary crop. Nasturtiums in particular grow so quickly, they are often unharmed by the aphid visitors.
Insectary plants may not be what you expect to find in an article about pest control, but often insects are our best defense against other insects. While much of our focus has been on pest species, it is the beneficial insects we truly want to promote and attract to our gardens. And it is these critters, among others, that we are sacrificing when we spray insecticides.
Pest resurgence is a common side effect of any pesticide application. Broad spectrum insecticides kill most insects on contact, whether pest or beneficial. Any beneficial insects that survive, starve without their pest food source. Without the beneficial insects, the pests either quickly rebound or another pest swoops in to take their place, leaving the garden more at risk than it was before and requiring repeat applications of pesticide.
Alternatively, by attracting a diverse and wide array of insects to your garden, you are ensuring a healthy balance of good bugs and pests. A thriving ecosystem is not one devoid of pests, but one where the balance of life does not tip in one direction or another. After all, if we lost all our aphids and caterpillars we would also lose our lady beetles and butterflies.
Instead of purchasing beneficial insects, choose plants that will attract them. Insectary plants support a wide assortment of insects, the good, the bad and the in between! Plants like yarrow, alyssum, flowering cilantro and dill have abundant, fragrant flowers that attract beneficial insects like lady beetles, lacewings, pirate bugs and many others.
Summer flowering cosmos, salvias, Echinacea, black eyed Susan’s and sunflowers attract a host of flying insects and birds, who are wonderful allies in your pest control toolbox. If you keep chickens or ducks (lucky you!) put them to work eating all those undesirable bugs. Ducks are voracious slug and snail eaters, and chickens excel in turning beds over for the season, eating leftover bugs and fertilizing the soil with their droppings (just be careful about leaving them in your garden unattended!).
Some preventative and cultural controls take time to show their effectiveness in the garden. For more immediate relief from pest pressure, it is sometimes necessary to employ mechanical controls. Do not be alarmed, you don’t need any fancy machines, mechanical controls are any that remove or exclude a pest from the landscape.
Setting out a shallow dish of beer to drown earwigs and slugs is a mechanical control, as is installing hardware cloth under raised beds to deter gophers. The benefit of mechanical controls is that they are environmentally low impact, provide quick results, and often prevent further predation. When plants are stressed, they can send out pheromones that attract more pests to attack. By reducing the stress load on the plant, you limit this signaling.
It is helpful to remember that the goal here is not eradication, but balance. A healthy garden is alive with a diversity of plant and animal life, with everyone keeping each other in check. We must learn to embrace a certain level of imperfection in our gardens, recognizing that they are supporting so much more than just ourselves. And isn’t that an incredible thing!