Using Organic Fungicide: Do Milk Or Baking Soda Really Work?

What can you do when you encounter a fungal disease on your fruit tree or garden plant? If you’re like me, you want to use a fungicide that really gets results but is still environmentally safe for plants, animals, and people.

I tested some of the most popular home garden fungicides, such as baking soda, milk, and copper fungicide spray to eliminate the guesswork for you! In this blog post, let’s explore popular organic fungicidal sprays and natural antifungal home remedies to determine which is best, so you can grow bigger.

Fungi in the Garden

You’ve probably heard me say that fungi like mushrooms are good for your garden because fungally dominated soil improves plant health and disease resistance. While this is true, not all fungi are beneficial to garden plants.

Common garden fungal diseases, like powdery mildew, rust, black spot, blight, verticillium wilt, fusarium wilt, and corn smut, can wreak havoc on your garden plants. Damp, cool nights or hot, humid conditions can make plants more susceptible to fungal diseases.

What Is Fungicide

A fungicide is simply a substance that kills or inhibits the growth of fungi. They are often used in farms and gardens to control or prevent harmful fungal infections that could damage or kill crops.

Common Antifungal Remedies For Plants

Home growers have used a host of things with antifungal properties to combat fungal diseases in plants, some being more effective than others. The following are readily available products that are commonly used as fungicides:

• Baking Soda - Sodium bicarbonate (baking soda) is one of the most popular homemade sprays for controlling powdery mildew, early and late blight, and other issues. Mix about 2 tablespoons of baking soda with one gallon of water (plus a couple drops of greywater-safe dish soap to help the solution stick to the leaves) and spray the plant’s leaves.

• Milk - I hear this remedy being used fairly often. People spray fully concentrated milk on plant leaves using a spray bottle in hopes that the alkaline milk will alter the pH enough to discourage the growth of fungi. Pro-Tip: Before you try milk in your garden, watch the video above or finish reading this blog post to see the results when I tested it for effectiveness!

• Aspirin - I use aspirin in the garden to prevent blight, verticillium wilt, black spot, fusarium wilt, and septoria blight on nightshade crops. It has been a popular remedy for decades; my grandparents used aspirin in the garden!

• Copper Fungicide - A commonly used commercially available fungicide that makes the leaf surface more acidic, creating a less hospitable environment for the fungi.

• Calcium Magnesium Citrate - This health food supplement is extremely effective at controlling blight and powdery mildew, plus it is a calcium and magnesium supplement for your plants. I have used calcium magnesium citrate on my tomatoes and squash; watch the video below to learn how!

• Sulfur - The fungicidal active ingredient in Captain Jack’s Orchard Spray is sulfur, one of the oldest recorded fungicides used in agricultural history. Some home gardeners do not realize that sulfur can be used on vegetables and other garden plants, not just trees.

• Neem Oil - Considered 100% safe for organic gardening, neem oil is effective as a fungicide and an organic pesticide!

• Tea Tree Oil - Did you know that tea tree oil was approved in 2009 as a fungicide? (Source) It is considered safe and effective on a wide range of garden plants.

Testing Popular Organic Fungicides In the Garden

Baking soda has been my failsafe-the “break glass in case of emergency” option for me! It is super effective for blight and powdery mildew because it raises the pH on the leaves, making them more alkaline. I was excited to see how it stands up in a test against other common choices.

I tested three of the most popular home garden remedies over several weeks to see which was the best: baking soda, milk, and copper fungicide. I did the test on squash plants with powdery mildew, spraying each solution on a plant once a week for three weeks.

After one week, the baking soda spray dramatically reduced the powdery mildew colonies on the leaves by about 60%, while the milk spray didn’t show a noticeable reduction. The copper fungicide showed shockingly good results with about a 90% reduction in powdery mildew at one week!

Which Fungicide Works Best: Honest Review

At the conclusion of the test (3 weeks), I was impressed with the efficacy of baking soda, especially for the cost and accessibility of the product. It had one drawback, however, and that was that it didn’t have a lasting effect; the powdery mildew tended to bounce back. For that reason, I recommend using baking soda as a preventative measure instead of a control.

The milk solution results were underwhelming, with very poor performance leading to an aggressive powdery mildew infestation on that plant at the end of three weeks. My conclusion is that milk is NOT an effective fungicide and better left in the kitchen.

The copper fungicide was the clear winner, with a 98% to 99% improvement! There was almost no powdery mildew colonizing even the previously covered lower leaves of the squash plant, and the top leaves looked perfect.

The takeaway? Technology and scientific developments have given organic gardeners some amazing tools that can yield great results when battling fungal diseases in the garden. Don’t be afraid to use those tools, like copper fungicide, when the need arises!

How to Use Fungicidal Sprays

To use copper fungicide spray, you will need a pump sprayer and water. Pro-Tip: When using products like organic pesticides, fungicides or similar products, always read and follow all the directions on the label! Read the product label for crop-specific instructions and a complete list of diseases controlled.

1. Shake - Shake up the copper fungicide in its original container.

2. Add Water - Put one gallon of water in your pump sprayer.

3. Mix - Add 0.5 to 2.0 fluid ounces of copper fungicide to the water, put the lid on the sprayer, and shake to mix.

4. Spray - Apply at the rate specified by the instructions: 1.1 gallons to 2.3 gallons of the diluted spray per 1,000 square feet. When spraying, make sure that the spray doesn’t contact people or pets directly or by drift.

5. Dry - The label warns that people and pets should not be allowed in the treated area until the spray has dried.

When to Spray & How Often to Spray

The best time to spray is early morning or late at night. I recommend spraying in the early morning after the plants dry from any dew.

Regardless of whether you are using an organic option or not, if you spray during the heat of the day, you are asking for damage to your leaves! It could even end up killing your plants because of the magnifying effect of the sun.

When you spray, start with a weaker solution or low dose and watch your plants for 2 to 3 days after spraying to see if it was effective. Then, you can decide if you want to try a stronger solution in your next application.

I prefer to use homemade antifungal solutions about once a week at most. Anything more than that could harm the plant. If you are using a store-bought fungicide, follow the instructions on the label.

Frequently Asked Questions