Powdery Mildew - How to Detect and Eradicate
Powdery mildew is a common fungal disease that can affect organic edible seedlings. It manifests as a white, powdery substance on the leaves, stems, and sometimes even flowers of plants. This fungal growth is caused by various species of fungi belonging to the Erysiphales order. Here's what a recent customer noticed with the seedlings she was growing on the Planted Places Planted Wall gardening system.
Q: I noticed some mildew on several of my new seedlings!
We’ve been getting a lot of rain, but also, I think my gardener watered the plants without my knowledge. And because the drip is still programmed for twice a day, coupled with cooler temperatures, my plants are soggy. I’ve since turned off the drip system and moved the wall to a more sunny spot. Any other suggestions?
A: Your little seedling definitely got some extra water recently from the looks of it.
We're happy to hear that you are already cutting back on the watering and moved the plants to a sunny spot – that’s the perfect thing to do!
I would also recommend that you remove the top layer of soil (1/2″ – 1″) and replace it with some fresh soil. This will help ensure the fungal issues don’t persist and end up affecting your seedling. If you notice after a few days that the soil is still very soggy, you can also move it to a well-ventilated spot or even put it near a fan for a few days to help dry everything out.
Powdery Mildew - causes and how to reduce exposure.
Conditions that favor mildew formation include dry foliage, high humidity, low light and moderate temperatures.
Organic edible seedlings, being particularly susceptible to environmental changes, may fall prey to powdery mildew. This fungus thrives in conditions with high humidity and moderate temperatures. Unlike some diseases that require standing water, powdery mildew can develop in dry conditions, making it a potential concern in indoor as well as outdoor organic gardens.
While powdery mildew doesn't typically result in the demise of plants, it can weaken them by inhibiting photosynthesis and nutrient absorption
Here's some things you can do to help curb powdery mildew from ruining your plants.
- Make sure your plants have good air circulation around them
- Place plants where they will get 6+ hours of sunlight each day
- Grow disease resistant varieties
- Avoid over fertilization. New growth is more susceptible. Try using slow release fertilizers.
Baking Soda (sodium bicarbonate), is possibly the best known of the home-made, organic solutions for powdery mildew. Most effective when applied in the early stages or before an outbreak occurs.
There's no CURE for Powdery Mildew, but you can control it. Try adding a tsp. or so to a spray bottle and add water. When the weather is dry, spray your water and baking soda mixture onto the leaves that are affected. Repeat when it rains. The ph level will create an unsuitable environment for the mildew spores to reproduce and spread.
When plants are growing in healthy soil, many disease and pests problems are minimized because the plants have a strong immune system. Try some of our soil and soil amendments to start growing nutrient dense edibles and thriving ornamental plants! You'll be amazed at how much easier it is to grow healthy leafy greens, herbs, and veggies. Everything is easier because your soil health is in tip top shape.