The accompanying plantation – folklore or scientific fact?
My Sicilian grandmother always planted basil next to her tomatoes. She claimed that basil makes tomatoes sweeter. Grandma never spent time in the library researching scientific papers on companion plants. Instead, she trusted the horticultural advice handed down by generations of home gardeners.
With dollars for agricultural research at a premium, there haven’t been many scientific studies to validate the effectiveness of companion planting in improving the quality of the home garden. That’s not to say that there isn’t some truth to the anecdotal story that many of us have heard from loved ones and other longtime hobbyists.
Recently, some universities have devoted time and money to studying these long-held beliefs, with interesting results.
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Companion planting can offer many benefits for the home garden. It is defined as the planting of two or more species in close proximity for the benefit of one or more species – essentially, a type of symbiosis. Some companion plants provide shade; others attract beneficial insects, suppress weeds, repel pests, improve soil condition, and may even improve flavor.
Taken together, these attributes go a long way in creating a healthy organic garden and reducing the need for pesticides. For example, fragrant plants like rosemary, lavender, thyme, sage, and marigold help repel certain pests.
The concept of accompanying plantation is old. There is evidence that it was practiced in China and Egypt over 1,000 years ago.
In North America, one of the best examples of companion planting is the “three sisters” method. Centuries ago, early American settlers were surprised to find three different vegetables growing together in the same plot near Native American villages. It was a strange sight compared to the carefully plowed rows and beds of identical plants they saw in Europe. Native Americans planted green beans, corn, and squash together. This was an efficient use of the available garden space, and each plant brought something positive to the garden:
- The corn supported the bean vines as they grew.
- Beans, which have symbiotic bacteria on their roots, are “nitrogen fixers” that turn atmospheric nitrogen into a form that plants can use. They added this essential nutrient to the soil, benefiting other plants, especially corn.
- The squash shaded the ground and helped retain moisture while deterring vertebrate pests with its prickly leaves.
Native Americans viewed these “three sisters” as precious gifts from the Great Spirit who watched over their crops and provided physical and spiritual sustenance for the village.
Scientists have not verified all claims about companion planting (eg, flavor enhancement), but research supports the biodiversity benefits of this planting method.
In her book “Plant Partners – Science-Based Companion Planting Strategies for the Vegetable Garden,” Jessica Walliser states that much of the recent information from universities and agricultural research centers takes us away from the long-held concept of companion planting. , benefiting individual plant species. Instead, we should think of the vegetable garden as an ecosystem with complex interactions between all the elements of the garden.
Using plant partnerships to achieve greater overall balance in the garden is the modern way to implement companion planting. Plant partnerships can be used for:
- Improve the structure and conditioning of the soil
- Manage weeds, pests and diseases
- Encourage biological control of harmful insects
- Improve pollination
The goal of home market gardeners is to have their own abundance of tasty and nutritious foods free from harmful pesticides. Companion planting offers a way to help achieve this goal, but it can be difficult to find reliable information.
When faced with a lot of conflicting information about companion planting, the best advice is to experiment, observe, and record what works for you when growing vegetables with different plant partners. When you think of your garden as a complete ecosystem, you will soon discover the benefits of using partner plants to improve results. And who knows, your tomatoes might be even sweeter!
For more information on the vegetable garden, visit mastergardenersd.org. You can get free gardening advice on the Master Gardeners Hotline, (858) 822-6910, or by email at email@example.com.
Donna McClay has been a master gardener at UCCE since 2018. She is an instructor at the beginner market gardening workshop. ◆