Plant Squash to Prevent Weeds?

Can squash plants really prevent weeds in your garden? Find out below…

You’ve probably heard of companion planting, but did you know that there is a scientific/chemical reason why some plants do – or don’t – grow well together?

Take squash, for example. A well-known component of the “3-sisters” trio, squash is supposed to do its part by suppressing weed growth. But does it really?

In fact, it does! Squash leaves contain a type of chemicals known as “allelochemicals,” which are known to inhibit the growth of competing species.

Basically, squash wants to crowd out anything that might come up nearby and try to shade it out!

This interesting article explains more about allelopathy, and how you can use it to prevent weeds naturally in your garden.

…When rain drips off a squash plant’s broad leaves, it takes with it allelochemicals that have been shown to suppress weed growth. Better yet, according to Stephen Gliessman, author of Agroecology: The Ecology of Sustainable Food Systems, these chemicals often inhibit weeds more than they impact crop plants.

Some plants exude allelochemicals through their roots, Duke says. In other cases, the chemicals leach from leaf litter that has fallen to the ground or from a dead, decaying plant.



Other common crop plants that have been shown to utilize allelopathy include beets, corn, wheat, oats, peas, buckwheat, millet, barley, rye, and cucumbers. Additionally, several species of sage have been shown to inhibit cucumbers and oats; sunflowers impact wheat and mustard; calendula affects wheat; and wormwood suppresses beans, fennel, and peas.

The easiest way for home gardeners to harness the benefits of allelopathy is by using cover crops or mulches that are allelopathic. Cover crops of wheat, barley, oats, rye, and grain sorghum are all useful in combating weeds, at least in part because of allelopathy. The allelochemicals they release break down quickly, so they won’t harm the next crop you plant in that space.

Mulch’s ability to suppress weeds is increased in certain mulches that leach allelochemicals onto the soil surface. Examples include coffee chaff, which gardeners can often obtain for free from a local coffee roaster, and wheat straw. When using these allelopathic mulches, allow the crop plant to become well established before applying the mulch so the leachate from the mulch will suppress weeds without harming the crops. Deep-rooted plants are less susceptible to the effect of allelochemicals, which tend to remain near the soil surface.




Rose S.

An avid gardener since childhood, I love sharing my passion for gardening with others! I have gardened in a number of different climates and settings, from large fenced garden plots, to tiny patio and container gardens, and I firmly believe that everyone can learn to grow at least some of their own food - no matter where you live. Growing your own food can help you take control of your own health and food supply, and there has never been a better time to get started!

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