If you’ve ever found a forgotten carton of expired milk in the back of your fridge, you might be tempted to throw it out. But before you do, consider using it to help your plants thrive.

Expired milk, surprisingly, can be an effective tool for boosting plant health and combating common plant diseases.

Milk is rich in nutrients such as calcium, protein, and vitamins, which can be beneficial for plants. Calcium, in particular, helps strengthen plant cell walls, promoting growth and improving overall health. 

When milk is diluted with water and used as a soil drench or foliar spray, it can provide plants with a gentle nutrient boost.

In addition to its nutritional benefits, milk has antifungal properties that make it a natural remedy for common plant diseases like powdery mildew.

This fast-spreading fungus often affects plants like squash, cucumbers, and zinnias, and it can be a headache for gardeners. However, milk sprays—made with expired milk—have been shown to help control powdery mildew effectively.

To use expired milk in the garden, mix it with water in a ratio of about 1 part milk to 9 parts water.  This diluted solution can be applied directly to the leaves of plants that are prone to powdery mildew or other fungal infections.

For a nutritional boost, the same mixture can be poured at the base of the plant, allowing the roots to absorb the nutrients. It’s important to avoid overuse.

Too much milk can lead to unpleasant odors or bacterial growth in the soil, so stick to a diluted mixture and apply it every 10-14 days.