How Humid Is Too Humid for a Greenhouse?

| 12/16/2016 4:28:00 PM

Bobbi PetersonA greenhouse is a great way to grow flowers, green plants, and even vegetables. It allows you to enjoy flowers, like orchids, that may not thrive in your home or yard. African violets, gloxinia, and ferns that might be temperamental in your living room will be colorful, verdant and lush in your greenhouse. You can continue to grow vegetables like tomatoes and peppers in a greenhouse when it’s too cold outdoors. Plus, you can grow herbs and greens all year.

You probably know greenhouses need humidity. Many plants, like ferns, thrive in a humid climate. Others, like orchids, absolutely need a humid climate to be healthy.

However, a greenhouse can become too humid for healthy plants. Read on to see why, and ways to fix too much humidity.

How Humidity Affects Plants

All plants need water to survive. Humidity is moisture in the air. Plants breathe it in through their leaves, so to some degree, humidity is good for plants needing moisture. That’s why greenhouses, as a rule, are humid.

Too much humidity, though, may cause disease in plants. Why? Because plant leaves will get wet, and fungi grow in wet plants. Mildew can get started in plants just as it can in damp areas in a house. In fact, fungi like the Botrytis pathogen and powdery mildew are all too common in greenhouses across the country.

Once these diseases start, they may spread rapidly. Humidity rises. If it builds up on the greenhouse’s ceiling, it will start to drip. When it falls on plant leaves, the drips can splash on healthy plants and infect them.