Is Beer a Good Plant Food?

Rumors abound about what household items work well as plant food, and many times, a grain of truth feeds the rumor. Such is the case with beer. Beer doesn't work as a natural plant food used full-strength or diluted, but some by-products of the beer production process do.

The overriding argument about why beer benefits your plants is that it contains substances, such as yeast and sugars, that feed helpful microorganisms in the soil or feed the plant directly. Some also believe the beer adds healthy bacteria as well, or that beer works like water to keep plants hydrated. However, it's better to keep beer in your glass than to share it with your plants.

Beer contains some ingredients that could help plants a small amount, such as carbohydrates and protein. But the carbohydrates in beer are mostly simple sugars, which don't help plants the same way that complex carbohydrates do. Protein exists in such small amounts in beer that it offers negligible benefits, providing only tiny amounts of nitrogen to the soil. Beer offers moisture from the water used in the brewing process, but that water comes at a price for the plants. The alcohol, which is prominent in the beer liquid, can harm plants, potentially burning them or inhibiting growth.

While you shouldn't pour beer over your plants, using beer by-products, such as spent hops and other grains, can help you develop healthy compost. Add the grains to your compost pile as green material. The dampness in the grains helps keep the compost pile moist while the grains provide nitrogen during decomposition, similar to the way grass clippings work in composting. The used beer grains often give off a strong odor initially, but some added wood shavings help temper the smell.

Just because beer can't feed your plants well doesn't mean you should keep it completely out of your garden. The powerful yeast odor draws slugs and snails, making it ideal to use in traps for those creatures. Pouring beer into a shallow dish with steep sides buried at ground level lets slugs and snails climb in, but after they fall into the beer, they can't climb back out. Using a cover over the dish reduces evaporation. Empty the dish daily and refresh it with more beer to keep the smell strong enough to attract the pests.