Black spot is a common fungal disease that affects roses at this time of year, but there is a natural method to help prevent it using a common kitchen ingredient12:48, 27 Jun 2026Gardeners are starting to reap the rewards of their efforts as their roses expand and begin to flower, though they ought to be aware that spring can prove a particularly difficult time for these popular blooms. Roses are vulnerable to a fungal condition called black spot, as the spores typically thrive when the soil heats up but stays damp from spring weather.‌This condition derives its name from the most distinctive symptom: large, patchy, dark blemishes on rose leaves that ultimately fall off, transmitting the infection across the garden. Black spot alone is unlikely to destroy roses completely, but it compromises the foliage so the plant cannot capture enough energy, rendering it far more susceptible to pests and other ailments.‌It will prevent roses from flowering correctly, leaving you with a barren and lifeless-looking plant that is also more likely to die back in summer as it battles to manage the warmer conditions.‌How do you maintain rose health?Joe, a gardener and founder of In the Wild Garden, has disclosed there is a natural yet remarkably effective approach to stop black spot on roses, or even help remedy it, by spraying them with milk, reports the Express.Joe stated: "Mix up a solution of one part milk (full-fat milk) to two parts water in a spray bottle. Spray the remaining leaves of the plant with this solution, and repeat every week."‌It might seem unusual, but when milk is subjected to sunlight, it generates compounds that are harmful to fungal spores, stopping them from multiplying.Milk will also form a thin layer on a leaf, making it significantly more difficult for spores to cling to the plant and serving as a protective barrier against infection.Applying milk will help ward off black spot in spring or decelerate the disease if detected sufficiently early, giving the plant a much greater chance of survival.‌How to use milk to combat black spot diseaseThe easiest and most efficient method to keep black spot away from your garden is to maintain it well. Black spot spores propagate through decomposing foliage, so ensure you're consistently collecting leaves or any other debris surrounding the base of your roses.Mulching your roses will also substantially help prevent black spot, as spores tend to splash onto the plant during rainfall. Covering the soil with compost or wood bark will help stop the infection in its tracks.Next, spray the milk solution on roses once a week. Simply mix one part milk with two parts water in an empty spray bottle.‌Use it to mist the leaves, aiming to lightly coat the plant rather than soaking it.Make sure you examine your plant at least once a week for signs of black spot. Should you spot it, strip the plant of all its leaves, dispose of them in a bin, and continue applying the milk solution.‌It's important to remember that milk can create an unpleasant smell, and it's best to avoid spraying during the afternoon when sunlight is strongest, as this will leave a sharp sour odour across your garden.A more effective method is to apply the spray in the morning, enabling the foliage to dry more quickly; alternatively, you can apply it later in the evening if you prefer.Joe added: "One word of warning would be to do this in the evening, as the smell of milk in the garden on a hot day is not great!".Article continues belowHowever, make certain your roses are completely dry afterwards if you apply the solution in the evening, as leaving the plant wet overnight may attract slugs or other troublesome pests.