Should You Use Beer To Fertilize Your Garden?

One of the best parts about spending a lot of time in the kitchen is that you often learn several ways to recycle that "unusable material" into something usable again. Cardboard egg cartons can be repurposed as bookshelf risers, and fruit and vegetable scraps can be tossed into a compost pile. So it's logical to think there's a recyclable use for your old beer, too — but you may want to reconsider before dumping any bottles out the window. While beer may be great for parties or football games, it shouldn't necessarily be used to fertilize your garden because it's not a complete fertilizer.

Beer, although brewed and not distilled, contains alcohol, which is a major no-no for plants of any kind. To thrive, plants need a fertilizer containing a mixture of micronutrients and macronutrients, and although beer does contain phosphorus and calcium, there's not enough to make it a viable plant fertilizer. A common brewski is typically made up of water, yeast, carbohydrates, and a small amount of proteins and other nutrients. Those carbohydrates, aka simple sugars, aren't the same kind of complex carbohydrates that plants use to thrive. Plus, just like sugar impacts the ABV levels of your beer, the sugars in beer will also negatively impact the growth of your plants and potentially attract pesky bugs.

If the carbohydrates (sugars) in beer are an issue for your growing garden, then so is the yeast. Intended yeast can have its benefits, but at the end of the day, it's still a fungus, which is the last thing you want growing among your precious tomato and pepper plants. Some may argue that the added yeast from the beer is good for your soil, but others argue against that claim by saying that your plants can get the yeast they need from better, natural sources, not one that comes attached to sugar and alcohol. There's also discourse about using stale beer versus new beer, but at the end of the day, there is anecdotal evidence that any type of beer will not serve as a viable fertilizer.

While the old wives' tale about using beer as a fertilizer may be a bust, that doesn't mean you can't make good use of those untouched bottles. Instead of dumping the contents into the soil, fill up an old takeout container or bowl with your choice of beer until about the halfway point to act as a cheap and easy trap to banish garden slugs. That yeast that's detrimental to your plants? Slugs go crazy for it, the same way they go crazy for your leafy greens. Once the little pests climb into the beer bath, they can't climb out, thus eliminating any slug infestations and finding an alternate use for old beer at the same time.