Homemade Spray for Black Spots on Roses

Affected roses can thrive if black spot is caught and treated early.

Black spot on your roses is one of the most frustrating plant problems. It can be persistent from year to year, leading to leaf loss and poor rose appearance. Buying resistant roses can help, but organic treatment is essential.

Types

Black spot is a fungal disease, so all black spot sprays are some type of fungicide. Among homemade, organic fungicidal sprays, those based in a baking soda solution are the most common. Other homemade black spot sprays use brewed cornmeal, vinegar solutions and a host of other common substances designed to create an inhospitable pH or other unfavorable environmental conditions for the fungus that causes the disease.

Making Homemade Spray

The simplest way to make black spot spray is to mix the desired active ingredient, such as baking soda, with water in an appropriate solution such as 1 part baking soda to 20 parts water. If brewing is needed--as is the case with a cornmeal spray--the ingredient is mixed with water, allowed to steep, then the liquid strained off and used as spray. Regardless of the preparation method, the solution is best stored in a clean, plastic spray bottle.

Application

Homemade black spot fungicide should be sprayed evenly on all rose bush leaves in a garden where black spot has been found, not just on affected leaves. The solution needs to be applied weekly until the end of the growing season. Reapply after every rainfall, recommends Good Earth Rose Care.

References

• Good Earth Rose Care: Mildew and Black Spot Control Options
• Dirt Doctor: Organic Recipes--Homemade