Growing Vegetables in Alaska Hardiness Zone 6A

Greenhouse Garden Growing Vegetables in an Extreme Climate

Mardell Gunn and her partner, Mark Kistler, aka Diz, had been gardening in Haines, Alaska, using standard hoop houses for several years. In 2016, they searched for a polycarbonate structure that could withstand heavy snow loads and humid summers while providing a protected environment to grow fresh, heat-loving vegetables that can’t be grown successfully outside. Specifically tomatoes. That’s when the internet led them to a 26′ Growing Dome. 

“If I recall, at the time, Growing Domes were the only polycarbonate dome greenhouse that we felt comfortable leaving up year-round. This year was a great test for it. We had wet, heavy snow almost 6 feet on top of the greenhouse at a time. I have to compliment the design. The structure is so strong. We never worried about failure, and wind didn’t affect it at all.” – Mark.

Modifications for Heavy Snow & Humidity

A standard Growing Dome Greenhouse can withstand 75 pounds per square foot of snow. Growing Spaces has also re-engineered and reinforced custom Growing Domes for places like Lake Tahoe, CA, where snow loads run upwards of 180+ pounds per square foot. 

Going into the building process, Mardell and Mark knew they wanted to make a few modifications to the standard Growing Dome on their own that might better suit their humid, snowy environment. The added measures included a pole in the center of their greenhouse that adds a bit of extra support and an extended covered entry area that relieves pressure from the doorway, allowing it to open easily. It is also quite beautiful. 

To reduce humidity, Mardell and Mark also opted to leave out the above-ground pond. Instead, it makes up for losing the Growing Dome’s main heat sink with concrete raised beds. Mardell said they “used several layers of earthbags filled with sand found on their property followed by chicken wire, then concrete, and a coat of black paint to attract the heat.  

“We also added extra ventilation and installed the undersoil fans included with the kit. I really think it’s helping to prevent mold.” – Mardell.

Growing Vegetables from May to October

Mark and Mardell don’t garden in their Dome all four seasons due to minimal hours of sunshine in the winter months. “We do not get enough light to grow without adding lights, which is cost-prohibitive because of high electricity costs.” So, they take full advantage of the growing season they do have.

From the third week of May to the end of October, Mardell grows anywhere from 150 – 200lbs of tomatoes. That is unheard of in Alaska. They have over 31 tomato plants, tromboncino squash, more than 33 peppers, and a ton of cucumbers. The squash is reaching 12 ft. high, taking full advantage of the vertical greenhouse space. 

“It is not a big deal down south, but here in Alaska, it is not easy to get an overabundance of tomatoes or peppers! My 26′ Dome allowed me to have that this year!!!  It is a gift for me to have tomatoes that actually taste good.”

– Mardell Gunn.

Investing in a Healthy Future

Mark and Mardell described themselves as “vegans who eat fish because fish is so plentiful here.” They currently have 3,000 sq. ft. of growing space stretched across mountainside land where they produce a lot of their own food and hope to for many years to come. 

“I call the Growing Dome our long-term disability. I hope to garden until I am 95, and I imagine as I grow older, my outdoor growing space will dwindle, and instead, I can see myself solely gardening in our Growing Dome.” –

Mardell Gunn.

It was a significant investment to have the greenhouse shipped up to Alaska from Colorado, but Mardell and Mark know that their Growing Dome Greenhouse will withstand another 25+ years.

You can find all of our Featured Growing Dome’s highlighted in our monthly newsletter “The Happy Grower,” on our social media platforms (Facebook and Instagram), and in our blog. At the end of the year, we create an annual calendar that includes every Dome of the Month. We send them to all Dome of the Month participants, along with a gift of Growing Spaces gardening goodies! Apply here.

Kenzie Jackson Marketing Director

I studied marketing at Eastern Illinois University and have been working as the Marketing Director at Growing Spaces since May 2019. What I love most about my job is getting to tell the stories of our customers in our featured dome articles. It’s all about connecting through storytelling, and it’s pretty cool to see all the different ways people use our greenhouses.

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