To add, or not to add, coffee grounds to garden soil

CUIZSINE & CULTURE From the garden

The following link from curiosity.com has a warning to absolutely not add coffee grounds to the garden soil, and even stated that spent coffee grounds are bad for the garden: https://curiosity.com/topics/whatever-you-do-dont-put-coffee-grounds-in-your-garden-curiosity/?ref=mbsht. I have a friend who, after reading this link, stopped her practice of cleaning spent coffee grounds out of the little K-cups, transferring them to a larger container and when a sufficient quantity had accumulated, taking the grounds out to the garden and scattering them on the soil. The friend said, “Never again would coffee grounds be going into her garden.”

The question: Are coffee grounds in the garden a concern?

Not adding spent grounds to the garden is a shame because our West Texas soils can use every bit of organic matter. The gist of the above link is this: Because coffee grounds are highly acidic, they should be reserved for plants like azaleas and blueberries, which, gardeners know, would not survive a West Texas summer anyway. But the biggest warning is that spent coffee grounds are full of caffeine, unless of course you drink decaf coffee.

So let’s tackle the first warning, that coffee grounds are acidic. This is exactly the reason to add them to the garden. Our West Texas soils are highly alkaline, presenting unique challenges — mainly micronutrient deficiencies. Adding an amendment that is acidic will bring these soils closer to neutral, allowing certain minerals to become available. This is good.

Next, the warning to not use spent grounds because caffeine causes death of plants growing close to caffeine-source plants, such as coffee trees. Perhaps this suggested suppression of growth is because, while coffee beans contain caffeine, coffee trees might compete with less hardy plants for space, sunlight, water and nutrients. But is adding coffee grounds a problem for the garden? One would have to add huge quantities of coffee grounds to alter soil properties. There are so many microorganisms in the soil and so many soil particles that any effect the caffeine may have becomes diluted, such that any harmful effects of caffeine in the soil are negated.

Also, how much caffeine is present in the grounds after preparation needs to be considered. If, after weighing the pros and cons, the gardener decides to amend their soil with coffee grounds, spread and then work them into the soil.