Key practices to manage diseases and pests in your garden: Part 2
By: Marlia Bosques Martínez (Part 1)
2. Increasing beneficial insects/microbes
When thinking about gardening, we also want to mimic certain things that happen in nature. If you look closely at a forest, you will notice harmony and balance between different plants, animals, and microorganisms. For instance, certain plants will attract pollinator insects with their flowers while others will provide many leaves that will eventually turn into beautiful compost. For this reason, having a diversified garden or farm which includes plants that provide a thriving environment for pollinators and beneficial insects to live will help decrease disease and pest pressure.
One way to achieve a diversified garden is by interplanting (also known as companion planting) your main or cash crop with a high pollen flowering plant. Specifically, interplanting is defined as the art of growing plants close to each other because they can increase or complement the other's growth or attract beneficial insects or decrease pests and diseases. This type of practice has been used for centuries by indigenous farmers and is still commonly practiced today by farmers and gardeners worldwide. Other benefits of interplanting include maximizing space, nitrogen fixation, supporting one plant by another, increasing nutrient uptake, reducing erosion, and water conservation. Consequently, your garden or farm will have higher crop productivity as well as an improvement of biodiversity.
There are many ways to interplant, and it all depends on what specific benefits you are looking for in your garden or farm. It will also depend on the climate, soil type, and water availability. A good rule of thumb is that farmers plant the main or cash crop 2 weeks before planting the other crop. This will allow the main crop to spread its roots without competing with the other crop. If you mostly plant in container pots, no problem! As long as the plant is 1 foot close, the main crop will benefit from the plant. Lastly, you want to plant annuals instead of perennials with your main crop because, at the end of the growing season or harvest, you will want to rotate your crops and/or apply compost to your container pot or bed.
Examples of interplanting:
Marigolds (edible flowers) and Calendula (medicinal properties) are bushy and low growing to the ground, go well with fruiting plants such as peppers and tomatoes.
Bee balm (bees love it!), borage (medicinal properties), and verbena (amazing cut flower) have a taller height, so it pairs well with leafy greens such as lettuce which is smaller in size and also provides shades.
If you want to learn more about interplanting and other tried-and-true examples, check out this extension factsheet!
Another excellent way to increase biodiversity, pollination, beauty, and decrease pest pressure is to have hedgerows in your garden. Hedgerows are usually found at the edges of farm fields or along roads to create protection, and they come in all shapes and sizes. They are dedicated living areas in your garden or farm that provide food, shelter wildlife by offering food in the form of leaves, flower nectar, berries, and nuts, as well as nesting and burrowing sites. At the same time, they help manage weeds, facilitate water conservation, provide windbreaks, diversify farm income, and much more! Some farmers have 30% of their area dedicated to hedgerows, but if you have a small garden with mostly containers, you can have a few container pots that include perennials that will provide habitat for beneficial insects. You can also do small blocks or rows in different areas of your garden or farm.
Here are some tips and information if you decide to incorporate a hedgerow:
Hedgerows should be mostly perennials, so you don't have to plant the following year again.
Have many native plants that thrive in your growing environment (beware of invasive species).
Plant a diversity of plants that can provide a year-round flowering sequence. This way, you will provide pollen to insects at all times.
If possible, try incorporating a mix of trees, shrubs, grasses, groundcover, and flowering plants.
If you have a farm, use drip irrigation to reduce time and water.
To decrease the maintenance of weeds, you can use a landscape fabric or mulch (straw or wood chips).
Remember, hedgerows could also be functional hedgerows because you can harvest part of the plants grown, so as mentioned before, it depends on what you are trying to achieve with your growing space.
Some of the beneficial insects you will find in hedgerows are bees, parasitic wasps, predator flies such as hoverflies, lacewing, ladybugs, and even birds!
Take in mind that for a hedgerow to look really nice, leafy, and flowering, it may take up to two years or more, depending on what plants you have.
If you don't have a windbreak or tall trees, plant some shrubs and bushes, so it helps your plants against strong winds.
There are many ways to do hedgerows, but here are some ideas you can incorporate!
Medicinal hedgerow- arnica, chamomile, garlic, echinacea, ginseng, calendula, and yarrow.
Herb hedgerow- sage, thyme, rosemary, lavender, dill, parsley, peppermint, and cilantro.
Flower hedgerow- marigolds, nasturtium, calendula, verbena, sunflowers, and sweet violet.
If you want to learn about hedgerows and other excellent examples, check out the OSU Extension Guide.
3. Working with the soil
Working with the soil is the most important piece for having a good growing year. When you have healthy and nutrient-dense soil, your plants are also healthy. It has been scientifically proven that pest and disease pressure is worse when you have unhealthy soils. Unhealthy soils could be a lack of essential nutrients, low organic matter, poor drainage, high erosion, and other factors. While there is a vast amount of information about soil health (lookout for an article soon), here I will share some tips and practices you could implement in your garden or farm.
No matter your soil, you should always be building it up. At the start of the season, many nutrients will be depleted from the soils from the previous growing year. If you do not build it up with compost and nutritious matter, your bank of nutrients will soon be depleted and no longer able to support the well-being of your crops. One of the ways we can build up that bank is by applying compost.
Lay down a few inches of well-rotted compost every time you put a new plant. This could be vegetables, chicken, worms, cows, mushrooms, or any other compost that will help increase the nutrients in your soil. Composts also add organic matter back into your soil, building soil aggregation and structure. You can also add compost to container pots. Once a month, you can also add green sand (high in potassium), which is really good for drainage if you have a lot of clay in your soil. Additionally, you can also apply glacial rock dust, which has high amounts of calcium and magnesium, which is essential for a healthy root system. Check out this great factsheet for resources and learning how to make compost!
After you amend with compost, you can fertilize your crops every two weeks to a month. The fertilizing frequency will depend on the crop and nutrient availability in the soil. Remember to always refer to the label to see how much you should apply. There are 2 types of fertilizer based on their physical structure, liquid and granular. Granular fertilizer is coarse; you can touch it and feel it (i.e., chicken manure pellets). Liquid fertilizer (i.e., fish emulsion) can be worked into the soil way faster than granular fertilizer (2 weeks to a month). The only downside is that it is more prone to nutrient leaching, which is a huge environmental issue.
Since liquid fertilizer provides nutrients faster, it is usually way more expensive. It also works better than compost for container pots (usually have a sterile potting mix) since they don't have many microorganisms to break down the compost. Learn more about agroecological fertilizers here!
Besides compost amending and fertilizing, here are other practices you can incorporate to improve your soil health:
Use mulch in all areas of your garden or farm. A mulch is a layer of material applied to the surface of the soil. Mulches help to conserve moisture, moderate extremes in temperature, and control weeds. Depending on the type of mulch, there are other added benefits such as using live mulch (straw, cacao shells, wood chips) to improve soil aggregation and granulation and increasing water absorption and retention. You can also use plastic or fabric mulch which can usually last a few seasons to a few years. If you want to learn more about mulches, check out this extension factsheet.
Implement conservation tillage systems such as no-till. It is an agricultural method for growing crops without disturbing the soil through tillage. No-till farming was practiced all around the world by indigenous farmers before colonization and industrialization of agriculture. Recently, it has made a comeback in agroecological communities and even conventional farms. Several research studies have shown that no-till positively impacts soil health, productivity, and profitability under extreme weather events of wet or dry conditions. Moreover, no-till may improve soil infiltration, organic matter, and soil structure. However, this is strongly dependent on time and soil type. Hence, while no-till has been beneficial in some environments, it has not been consistent in others.
In most farms, it is also essential to partner no-till with cover crops. They are plants that are planted to cover the soil rather than for the purpose of being harvested. They serve many functions, including preventing soil erosion, recycling and restoring nutrients, and controlling weeds. They are usually seeded in the fall and killed before spring planting. However, in tropical regions planting time may vary greatly. UF extension provides a great list of cover crops that may be used in subtropical and tropical regions. If you want to learn more, check out this great list of resources about conservation tillage and cover crops.
While this is by no means an exhaustive list of all the different tactics and practices to manage disease and pests, these suggestions most definitely will help your plants and soil improve their health. Make sure to read our previous articles, “Let's Grow a Garden! Part 1: Temperature, A Key Factor for Growing Our Food” and“Are Your Plants Sick? Plant Disease Basics”.