5 Ways to Prevent Pests in the Garden

Have you ever thought if you could just keep the pests and diseases out of the garden in the first place then your crops would grow great? Although we can’t always keep out the pests unless you are growing plants inside, you can take some steps to reduce the pest problems. Here are five steps you can take to reduce your pest problems.

1. Clean Up the Garden

During the winter, you don’t usually see any pests, so where do they go? Various insects overwinter in different stages. Tomato/tobacco hornworms overwinter as pupa, so if you had them on your tomatoes, then you should till the soil up after you discard the plant and see if you have any pupae and discard them (Fig. 1). Other caterpillar pests and beetles also overwinter as pupae in the soil.

Figure 1: Tomato hornworm larva and pupa.

Squash bugs overwinter as adults under leaves and rocks and in plant debris near the garden. You can clean up your leaves and put them in your compost, checking to see if they are there. If so, you can put them in soapy water.

For diseases, several types overwinter as spores on plant debris. Once the conditions are right for them, that’s when they will reinfect your plant. You want to make sure that you clean up any leaves that were diseased and pull any plant parts left in the ground. You’ll want to bag and discard any diseased plants.

2. Grow Resistant Varieties

If you had problems with diseases or nematodes, starting seeds with resistant varieties will help solve that problem the next season. For example, if my tomato got fusarium wilt which causing yellowing and wilting of the plant, then I may want to start seeds of ‘Early Girl’ tomatoes that have resistance to the disease since many diseases come back year after year. Many of the seed packets have codes for what diseases they are resistant to. Since Fusarium Wilt have different races, there are 3 different codes (F, FF, or FFF) depending on which races they have resistance.

By growing your own plants from seed, you can select plants based on the situation going on at your home. 

Below is a packet I saw at Home Depot that had resistance to early and late blight (Fig, 2).

Figure 2: 'Cloudy Day Hybrid' tomato seed packet with resistance to early and late blight.

3. Block them Out

You can block out some pests by putting up physical barriers, such as floating row covers or insect mesh. These covers can be place over the plants or supported on hoops (Fig. 3). Make sure you have the edges secured or weighed down so that the pests can’t simply go under them. These work well for caterpillars, maggots, aphids, and squash bugs.

Figure 3: Insect mesh on hoops can keeps our several different pests.

4. Try Companion Planting

When I plan out a garden, I look to see which plants to place next to each other to get the most benefit. I recently planted bare-root strawberries. I looked to see the best companion plants for strawberries and I saw that lettuce and onions were good . Lettuce can help shield the berries from birds and onions can deter pests (Fig. 4). Even peas are good next to strawberries in order to add nitrogen to the soil and strawberries need a lot of nutrients. I also added borage to help attract pollinators and predators for any pests (Fig. 5).

Figure 4: Lettuce and strawberries planted together as companion plants.

Figure 5: Borage planted next to strawberries growing in a vertical planter.

5. Keep your Plant Happy

One way I always say to prevent pests is to keep your plant healthy. Plants are more susceptible to pests and diseases if they are stressed. The plants are not as able to withstand the damage if they are unhealthy. In order to keep a plant healthy, it needs to have proper irrigation and fertilization.

It should also have proper spacing. In general, plants won’t grow well, especially root vegetables like carrots and beets, if they are not thinned out (Fig. 6).

Figure 6: Result of carrots planted too close together.

Also make sure your soil is healthy, teeming with beneficial microorganisms. Adding compost can provide that. Microorganisms can provide plants defenses against pests and diseases.

Key Takeaways

These are just a few of the ways to prevent pests in the garden. It is difficult to keep everything out, but the more proactive we are, the less likely pests will be a problem. Which way do you use and what are your biggest problems? Comment below.

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