
My friend Robin got a greenhouse this year and I’ve been beside myself with jealousy ever since. It’s really a gorgeous little space and I want one. Badly. So I asked Robin if she would mind writing up a little guest post about her greenhouse and some tips for those of us who are considering investing in one. ~ Willi

For years my husband and I have dreamed of adding a greenhouse to our mid-sized residential garden in Seattle. In 2008, we invested a meager $100 on a cheapie hollow aluminum frame greenhouse that was held together with plastic clips and covered with plastic sheeting. During the spring and summer, we enjoyed this foray into greenhouse gardening, but fall rains rapidly rusted out the cheap frame. Then, in our record snowfall, the whole thing came tumbling down. I was able to recycle some of the aluminum tubing as training stakes, but the rest was a big pile of trash. Learning from our not-too-costly mistake, we resolved to add a more permanent, sturdy structure to the garden. Our challenge became finding an affordable greenhouse that fit our garden aesthetic.
Initially, my handy husband Bob ordered greenhouse construction plans from The New Yankee Workshop. But, before he got started building, we went to the 2009 Northwest Flower & Garden Show where several greenhouse vendors were displaying their floor models. So, we did some comparative shopping.
First, we looked very briefly at some of the fiberglass greenhouses. Honestly, they pretty much gave me the creeps. They were dark, with short ceilings, and to my eye, they were ugly. Then, we dreamily window-shopped the booths filled with ornate glass greenhouses framed in powder-coated steel with fancy filigree, but they were beyond our budget. Finally, I found myself talking with a couple of vendors offering reasonably priced greenhouses similar to the style Bob planned to build from scratch. They offered twin polycarbonate walls, cedar or redwood frames, a few footprint sizes, and simple pre-fab construction that looked doable to me.

After comparing prices, time requirements and construction materials and formats, Bob agreed that these kits were a good option for us and much less expensive than building the greenhouse from scratch with the plans. So, we ordered the Mt. Hood Sunshine greenhouse kit. And about three weeks later it arrived. Within just a few hours on St. Patrick’s Day, Bob had put it up on our back patio—with just a little help from me.

I should note that we negotiated a few custom modifications to the standard kit (without being charged for the difference). First, we ordered two Dutch doors rather than the standard one door with an opposite self-opening floor vent. This adjustment allows us to enter from the patio and exit on the opposite side into a renovated garden bed. This simple change helped us better integrate the beds surrounding the greenhouse into our overall garden plan (see above).

Having worked in large greenhouses, I wanted multiple shelves made from expanded metal instead of the redwood slat shelf that came standard with the kit (see above). Metal is easy to clean and doesn’t harbor insect and disease. Along with making these modified shelves, Bob changed the door hardware to improve the locking system and allow us to anchor the top of each open Dutch door to nearby fence posts. And, he added ground-bolts (available from Sunshine Greenhouses) to keep the structure in place should it get excessively windy.

Our greenhouse is a beautiful and well-used addition to our garden (see below). It has served us well for propagating edibles from seed, growing tropical lilikoi, and ripening tomatoes well into fall. It serves as a backup location for leafy greens and other hardy cool season crops just in case the ones I have under hoop houses don’t quite stand up to winter. We haven’t added lights or heat to the greenhouse, but even on cool fall evenings, it manages to trap enough heat to remain warm overnight. We’ll see if additional sealing is required in winter.

The small, semi-permanent structure is just right for our residential garden. Sure, I could fill an enormous greenhouse given the chance. But, by carefully planning my planting rotations, monitoring my crops regularly for pests and disease, and spacing my plants carefully, I’m content with the amount of greenhouse space I have. At least once daily regardless of weather, I duck inside where I harvest fresh, homegrown, organic produce; inspect plants for pests and disease; water; or just simply soak up the warm, moist, herbaceous atmosphere always waiting inside my little horticultural dream house.

Here are a few tips if you’re considering a greenhouse of your own:
Kit, DIY Plans, or Installed? A kit worked for us, but we did make several modifications that required additional investment and Bob’s handyman skills.
Consider Space. Think about how you plan to use the greenhouse and how much footprint you have for it. You’ll need a solid, level spot on which to build your new structure where it will get enough – but not too much – light and warmth from the sun.
Make sure you have water nearby. In the heat of summer, I often had to water in the greenhouse a couple times a day.
Controlling heat. Our greenhouse came with a roof vent that requires no electricity yet opens automatically as heat builds too high. On extra warm days, we have the option to open both Dutch doors open to create a great pest and disease-deterring cool breeze.
To read more about Robin’s greenhouse and her really amazing edible landscape, check out her blog Garden Help.