This final segment of our series deals with our least favorite part of organic gardening – those pesky unwanted insects. Here’s how to keep them out without using chemicals.
Part Eight – Garden Pests
The worst thing to a gardener is seeing a beautiful plant begin to produce its bounty, only to come back at harvest time to find some insect pest has ruined it. This most commonly happens with things like summer squash and tomatoes, but all veggies are susceptible to something. There are plenty of resources out there about how to organically and physically control garden pests that are particular to each type of plant. These few ideas pertain to all plants and your garden in general.
Physical barriers. Depending on what you’re growing, garden pests may prey more on the youngest of your plants before they can develop a strong defense. Row covers can help prevent many of these, especially on brassicas like broccoli and cabbage. Place row covers tightly over the plants and secure them along the sides to prevent pests from getting to the seedlings. For plants that are susceptible to cut worms and slugs, simple collars placed around the base of the plant (made from paper cups or recycled soda bottles) can protect the seedlings until they are too big for the pests to conquer.
Hand picking. This is the most organic, and time consuming, way to rid your garden of pests. As we tend our gardens, we are constantly checking our plants for signs of problems. For example, we turn up the leaves of squash plants to look for eggs of squash bugs. When they’re spotted, the entire leaf is removed and taken from the area. It’s much easier to remove the eggs than the bugs themselves, but sometimes it just can’t be helped. We often pull insects by hand. Just be sure you know what the pests look like and distinguish them from the beneficial instects. Insects, like wasps, garden spiders and Praying Mantis, should be left in the garden.
Trap crops. Trap cropping involves planting one type of plant to draw pests away from another. The trap crops are often a plant within the same family as the ones you want to protect; other times, it’s a flower or herb. We’ve discovered the pests that enjoy eating our lettuce and arugula enjoy mustard greens even more. So we plant mustard between our rows of other leafy greens and get a much better harvest. The same goes for blue Hubbard squash planted along the perimeter of rows of summer squash. The squash bugs are attracted to the blue Hubbard and we can remove the plant, along with the bugs, before they infest the remaining plants.
With trap cropping there are a few key things to remember: First, plant the trap crop so that it matures before your main crop. This way, the bugs are more likely to leave your main crop alone while they go for the trap crop. Second, monitor your trap crop closely. Removing eggs before they hatch is much more effective than removing the insects themselves. Third, remove the trap crop (and the insects) if necessary. If the insect pressure gets too great on the sacrificial plants they will die and the pests will move on to your main plants. In this case, you may want to make successive plantings of your trap crop to give yourself time to harvest your main one.
Dusts and Sprays. There are many sources for different concoctions you can put together yourself from items in your own kitchen that will deter or kill garden pests. We’ve used a spray made from vegetable oil, dish soap and water as a spray for white fly. Or, sprinkle a combination of flour and cayenne pepper on squash plants to kill squash bugs. There are also organic commercial sprays on the market you can buy, like Neem oil. See our article on using herbs for protection in the garden for a few homemade sprays that may help.
Companion planting is the idea that certain types of plants do better when paired with specific other types. It’s been said for years that tomatoes love basil. Native Americans planted corn, beans and squash together to benefit each other for both nutrients and weed suppression. We frequently plant marigolds around our plots to keep pests away. These companion plantings can be helpful in home gardens, especially, since they are more likely to be planted in closer proximity to each other than in commercial operations.
Keep in mind there are also bad companions for certain plants. For example, don’t plant tomatoes near sweet corn. They both compete for the amount of nitrogen available in the soil. For more information, see our Companion Planting Guide.
Through this series we’ve tried to give you as much information as possible about how to plan, start and maintain your own garden. This information is nowhere near comprehensive: there are so many resources out there you can use to continue your journey. We do this for a living and are still learning year after year. We suggest you read as much as you can about the different aspects we’ve touched on, try one or two new ideas each season, and keep what works for you. The important thing is that you enjoy it and continue it.