Can You Still Eat Sage With Powdery Mildew?

Sage’s earthy aroma makes it an excellent addition to various dishes. Additionally, its medicinal properties are another reason we love this herb. However, you might be concerned if you notice a white layer or powdery mildew on your sage, making you wonder whether it is still safe to eat.

You cannot eat sage with powdery mildew, which indicates that fungi have infected your sage. Exposure can trigger allergy symptoms, such as labored breathing, constant sneezing, headaches, and watery eyes. 

This article covers why powdery mildew is growing in the first place and how to keep these fungi growth in check. Read on to understand why you shouldn’t eat sage with powdery mildew. 

Will Eating Powdery Mildew On Herbs Make You Sick?

In most cases, eating powdery mildew on herbs can trigger symptoms such as: 

  • Blocked nose
  • Continuous sneezing
  • Difficulty breathing
  • Eye irritation
  • Headaches
  • Lethargy
  • Rashes

However, you might see other symptoms besides these, so if you notice any of these or other strange symptoms, you may want to visit your doctor for testing and treatment.

What If You Wash the Powdery Mildew Off the Sage?

Powdery mildew grows in a thin layer on top of the leaves, and if you’ve tried rubbing the fungi with your fingers, you’ll notice that it falls off quite easily. Does this mean you can wash it off and then use the sage for culinary purposes?

Actually, you removed the spores from the leaves, which are responsible for spreading these fungi to other parts of the plant and nearby flora. But you can’t use the sage because these fungi can change the taste of the herb significantly. 

If you’ve already harvested the sage leaves and they have powdery mildew, the best option is to discard them. However, you shouldn’t add it to your compost as it can still spread to other plants in your garden.

Why Is Powdery Mildew Growing on Your Sage?

Powdery mildew needs three things to thrive in any space: 

  • Heat
  • Humidity 
  • Food source

The food source is your sage, while the heat and humidity depend on where you grow the herbs in your garden. Whether it’s been a hot and humid summer or it’s been a dry yet cool summer, there can still be powdery mildew on your sage. Why? 

Let’s take a look at the two reasons this could happen.

Crowded Growing Space

When you keep several plants close together, it increases the humidity. As you may already know, plants require water to survive. However, most of the water that you give your plant doesn’t always go toward making it grow. 

In fact, most of it gets lost due to a process known as transpiration. The water in the flowers, leaves, and stems evaporates, and as a result, there’s an increase in the water vapor in the air surrounding the plant. 

When you keep too many plants next to each other in the same growing space, there are high concentrations of water vapor in the air. Lack of ventilation in the grow space will exacerbate the problem. 

During the day, the temperature increases, so the air can hold larger volumes of water vapor. However, as it cools down at night, the air no longer has the same ability. This causes condensation to take place, making it easier for powdery mildew to grow.

However, it’s not necessary for water to be on the leaves for these fungi to catch on. 

Shaded and Damp Growing Area

If you’re growing your sage in an area without sunlight, it’ll experience a powdery mildew outbreak. When you water plants in these locations, the soil will remain damp as the excess water won’t evaporate into the air. 

What Can Powdery Mildew Do To Your Sage Plants?

Powdery mildew will harm the flavor of your sage. So what else will happen to your sage plants if you let powdery mildew spread everywhere? 

Stops Photosynthesis and Distorts New Leaf Growth

When fungi create layers on top of the leaves and continue growing, they become thicker, preventing photosynthesis. As such, the affected leaves will be unable to produce food, and if left unchecked, the leaves will begin to wilt, turn yellow, and eventually fall off.

When sage plants are afflicted with powdery mildew, it retards new leaf growth, and the newer leaves on the plant won’t look the same as the older ones. The fungi cause the fresh leaves to distort, making them look diseased. 

It Spreads Quickly and Decreases Your Overall Yield

Powdery mildew can spread to surrounding plants in your garden quickly. One day, it will be on your sage plants, and when you go to your garden the next day, you’ll notice it’s also growing on other herbs in the garden. 

If the fungi spread to other plants, some might die without early intervention. And even if you do manage to treat the infection, you will have spent productive time trying to combat the fungi, which will bring down the yield of the plant significantly. 

Fungi Can Cause Your Sage To Die

The fungi can also cause all the flora to die slowly if you don’t take action to stop them from growing.

How To Prevent Powdery Mildew From Growing on Sage Plants

Powdery mildew is destructive and, if left unchecked, can destroy your entire garden. That’s why you need to prevent it from happening in the first place. Let’s look at how we can do that. 

1. Ensure Growing Space Is Sufficient

Since you don’t want humidity to build up, the best option is to adequately space the plants, but this depends on how much growing area you have at your disposal. 

The recommendation for sage is to keep each plant at least 12-18” (30-46 cm) apart. 

While you may be able to get away with reducing the space even further, it can increase the chances of powdery mildew growing. Also, your sage’s yield will decrease because it lacks sufficient growing space. 

2. Prune Plants Regularly

At least once during spring, prune your sage plants when they get bushy. Pruning will encourage new and bushier growth if it gets too thin or leggy. Don’t forget to cut shoots that look like they will flower, and keep an eye on the stems of the sage.

3. Ensure Your Sage Plants Have Plenty Of Sun

You can grow sage with grow lights, but they must be on for 14 – 16 hours daily. Ideally, you should find locations that regularly receive at least 6 hours of direct sunlight. If the soil doesn’t receive enough sunlight, the soil can get too damp, leading to powdery mildew growth. 

4. Water Your Plants Appropriately

If you want to keep mildew off of your plants, be sure to water the plants in the morning for sufficient time for excess moisture to evaporate. Avoid watering from above to prevent water from settling on the leaves and increase the chances for mildew to form. 

5. Use Fertilizers Appropriately

While nitrogen-based fertilizers promote fast growth in sage plants, you should avoid using too much. The problem with over-fertilization is that the plants will create new shoots vulnerable to powdery mildew, but older growth is always more resilient.

If you want to use fertilizers, look for slow-releasing ones to ensure your plants get the right amount of nutrients.

Final Thoughts

Avoid eating sage with powdery mildew, as exposure to the fungi can cause respiratory issues. Powdery mildew can hamper the growth of your sage plants and change their taste for the worse. Follow the best practices highlighted in this article to prevent these fungi from growing on your herbs.

Alexander Picot

Alexander Picot is the principal creator of, a website dedicated to gardening tips. Inspired by his mother’s love of gardening, Alex has a passion for taking care of plants and turning backyards into feel-good places and loves to share his experience with the rest of the world.

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