The Surprising Baking Ingredient Gardeners Swear by for Healthier Plants

If you've spent any time on #GardenTok, you may have seen gardeners touting the benefits of molasses as a fertilizer. The problem, however, is that this isn't grounded in science. “There is no research-based information that supports the use of molasses as a fertilizer,” says Gene Fox, an agent for North Carolina Cooperative Extension. He does say, however, that molasses has plenty of value in the garden, when used correctly. Here's what you need to know.

What Molasses Does in the Garden

Molasses’ power in the garden lies in its ability to feed beneficial microorganisms in the soil that play a vital role in plant health. Molasses is food for soil microbes—tiny living organisms like bacteria, fungi, and protozoa—that decompose organic matter, improve soil structure, and make nutrients available to plants, Fox says. “Molasses is an organic soil amendment, not a fertilizer.”

Plants cannot use the sugar in molasses, Fox says, so diluting molasses with water and spraying it on leaves won’t feed plants. Diluting it with water and pouring it on the soil around your plants won’t feed plants, either. Neither their leaves nor their roots can absorb the sugar, Fox says. Molasses is often an ingredient in commercially prepared fertilizers, but it’s combined with other organic fertilizers that plants can absorb. It’s those other organic fertilizers that feed the plant, not the molasses.

Using Molasses in Compost Tea

There is a smart and effective way to use molasses in the garden: Compost tea. This is an organic liquid fertilizer made by extracting the beneficial microbes from compost and encouraging them to reproduce. The most common way to make compost tea is to mix compost and a tablespoon of molasses in a bucket of water, and aerate it with a small aquarium pump. The pump adds oxygen to the mixture, which those good-guy microbes need to respirate and reproduce. The molasses feeds those microbes, so they grow and make more microbes. The result is a bucket of beneficial microbes that will foster a healthy garden ecosystem.

To use compost tea as a liquid fertilizer for your plants, Fox recommends drenching soil with it twice a year, once in the spring before you plant, and again in the fall after your garden is done for the year. The tea will feed the microbes in the soil and build healthier soil.

You can also use a mixture of molasses and water—one tablespoon of molasses to five gallons of water—as a soil drench, but it won’t nourish microbes as effectively as compost tea.

Using Molasses in Compost

You can also use molasses to amp up your compost pile, Fox says. Molasses works as a sort of energy drink to feed the beneficial bacteria, fungi, and other microorganisms that make compost so valuable to your plants.

Mix ¼ cup of molasses per gallon of water and spray or pour the mixture on your compost pile. Let it seep into the pile. Feeding the microorganisms in the pile will speed up decomposition, meaning you get ready-to-use compost faster. The sugars will encourage microbes to grow and multiply, making the compost a powerful addition to the soil in your garden. Molasses diluted with water is a great way to activate a new compost pile because it can kickstart the microbial activity needed to turn a pile of leaves and kitchen scraps into compost.