Controlling the sun: Greenhouse owner discusses protecting plants in summer

Having a greenhouse around for gardeners in the colder, winter months is crucial for anyone looking to keep the growing season going year round or get an early start in the spring. But in the summertime, the architectural benefits that help keep plants warm in a greenhouse in winter can prove detrimental with the warm, arid Columbia Basin summer.

Stephanie Suarez of Moses Lake has picked up gardening in the past couple of years and built her own greenhouse shortly after the pandemic lockdown came into effect. Her first summer gardening was a learning experience, losing her first crop of plants after putting them in the ground too early.

Suarez has learned some tips and tricks in the past year and a half and even started her crop of plants and vegetables in the winter this year from seeds in her greenhouse. With a partial brick floor installed and a heater in the middle of the 5-by-10-foot building, she said she didn’t have any issue keeping her plants warm while temperatures were still cool.

Keeping things cool has been another story, she said.

“I watch the temperature every day; that’s the first thing I check every day when I wake up in the mornings,” Suarez said. “I have watering meters in the plants to see if I’m overwatering or underwatering them, which is a fine balance, too.”

Suarez said the summer sun can push the temperature inside the greenhouse well past 100 degrees Fahrenheit. She said she ordered a black shade cloth from Amazon shortly before the heat wave hit in June to drape over the roof of the greenhouse and keep some of the sunlight out.

With the help of some fans inside and vents that open when the temperature reaches a certain point, the shade cloth has been able to keep the temperature down to around 90 degrees inside the greenhouse, Suarez said.

Pretty much her entire garden is started from in the greenhouse, she said. A variety of basil plants, other herbs, tomatoes, green onions, carrots and beets are just a few of the variety of things growing in the greenhouse behind Suarez’ home. Certain plants she keeps in grow bags, which she can pull out of the greenhouse and set in the shade for periods of the day to prevent them from getting too warm.

Suarez said she’s had to move some of her plants around, too, inside the greenhouse after noticing they were getting too much sun.

“I had a couple of big basil plants that were getting really warm and I have a lower shelf underneath the main shelf, so they go into the shade constantly and stay cooler that way,” Suarez said.

In addition to keeping an eye on the temperature inside the greenhouse, Suarez said one of the biggest keys is keeping up with the watering on warmer days in the summer. She said she typically waters her plants twice a day, but has gone up to about four or five times a day recently with temperatures near triple digits.

To prevent diseases or bugs from becoming an issue in one’s greenhouse, Suarez said good airflow is crucial. She said keeping the sunlight trapped in the wintertime isn’t too bad, it’s getting that air circulating and cooled down in the desert summer that’s crucial.

“You’ve gotta be able to open the doors and let that air circulate, but at the same time you need to be able to regulate the sun that’s coming in there because that sun will come in and get trapped,” Suarez said.

Before she had her fans and shade cloth in place, Suarez said she was forced to pull all of her plants out of the greenhouse in May, when temperatures rose outside, and place them on sawhorses in the shaded area beside her home for two days.

As a new gardener, Suarez said having a greenhouse has been a learning process, but also a huge help in learning when to plant and how to best help those plants thrive. She said she’s in the process of getting her starts for fall crops ready and plans to have those harvested in late October to mid-November, depending on the weather.

Casey McCarthy can be reached via email at cmccarthy@columbiabasinherald.com.