I built the best backyard greenhouse and you can, too

I started a greenhouse last fall and finished it this spring. Someone who knows how to build things could have probably completed it in a weekend or two, but I knew I wanted to give myself a lot of time for mistakes and do-overs. I’m very happy with the results.

The finished greenhouse

First things first: these are the greenhouse plans I used. If you use these, read through them first and pay attention to his July 11, 2008 update that appears at the end of the post.

I modified the plans for my purposes. For example, as you can see in the picture above, the door is slightly off center. I did that to accommodate the layout for the raised beds inside the greenhouse. Mine is also significantly smaller. His plans are for a 12’ x 32’ greenhouse. Mine is 10’ x 12’. But I like the plans because they are so adaptable to your individual situation and goals. They are, in fact, the best plans I looked at, and I looked at A LOT over a very long time before I finally decided on these.

Also, I know it looks quite utilitarian, but I think it provides a good foundation for more creativity. I knew mine would have lots of plants around it, so I didn’t bother too much with artistic details but you could, if you were so inclined.

Why did I build a greenhouse

Let me first say why I didn’t build a greenhouse.

• I did not build it to be self-sufficient in food. Self-sufficiency is a myth. The way to navigate the climate crisis is to be more community-oriented and to not have a bunker mentality.

• I did not build it to be able to grow and consume more local food. Local food is often cited as a way to reduce carbon emissions. That belief has to do with the very intuitive idea that transport is a big contributor to the carbon emissions associated with food. However, as detailed by this very well-documented post from Our World in Data: GHG emissions from transportation make up a very small amount of the emissions from food and what you eat is far more important than where your food traveled from. I will write more posts in the future about diet and regional food systems, a subject I’ve researched and written about a lot as part of my past academic work.

Why I did build the greenhouse. The greenhouse in and of itself is not a practice that is going to reduce my carbon emissions. Rather, it’s a practical addition to the overall business that will allow me to serve my small customer base better.

• Season extension. I’m planning on putting herbs and flowers in here starting in March. That’s much earlier than I can typically put plants outside. This should allow me to be ready with herbs and flowers at least 4 weeks earlier than I would be otherwise.

• Increased amount of space for seedlings. I currently start all my seeds in the basement. The greenhouse gives me more space for seedlings, especially those that can handle cooler temperatures.

Also, I do like kale a lot, and I think that this greenhouse will allow me to grow kale and other greens all year long. I’ll test that out this winter. Also, I’m finding that peppers just love the heat in there, and I’m hoping that many of the tomatoes that would otherwise fail to ripen in my garden when it gets to be cool at night, like this week, will ripen in the greenhouse.

Anyways, whatever the reason (and yours will very likely be different than mine), this greenhouse is easy-to-build, inexpensive, and sturdy….all good things!

Building the greenhouse

Here are some pictures that document the greenhouse building process.

Because the post that I linked to at the top so clearly lays out the steps to building, I don’t think it is useful to repeat that here. But, because that post was written over a decade ago, I do think it useful to give you an idea of how much I spent on materials. I bought materials as I went so costs were spread out over a year or so.

• Raised beds are from Amazon

  • 1 2’ x 8’ at $80

  • 3 2’ x 4’ at $50/each= $150

• Soil, is a mix of compost and the sod I removed. Free!

• Slag sand is from Hammond Farms. Approximately $30 (I ordered 2 yards but used most of what I ordered on pathways elsewhere in the garden).

• 12 10’x 3/4” PVC pipe at $5.61/ea (current pricing)=$67.32

• Greenhouse plastic from Northern Greenhouse

  • 10 mils Clear, 10ft x 15ft = 150sqft x 1 = 150sqft
    @ $0.44 per sqft = $66.00

  • 10 mils Clear, 12ft x 15ft = 180sqft x 1 = 180sqft
    @ $0.44 per sqft = $79.20

• 15 PVC Snap Clamps from ACF Greenhouses at .60/each=$9.00

• Greenhouse batten tape. I used a fraction of the $12.95 roll I bought=$2.00

• Plywood. I got from someone on Nextdoor=$50

• Lumber. I’m going to have to estimate. I used pressure treated wood because it will last longer and it won’t be touching the soil where I grow food. Using a calculation of $.75/linear foot (which is high) and using approximately 123’ of lumber for the foundation and end walls, .75 x 123’=$92.25

• Weather proofing paint, $50 (estimate)

  Grand Total=$675.77

There is also the cost in there for nails, but I think that was just a couple of bucks.

You could easily reduce this cost by building the raised beds or not using them at all, by keeping your eyes peeled for free suitable lumber, and by not using slag sand. The secret, I think, is just knowing what you need and giving yourself time to collect items. I don’t think you should skimp on the greenhouse plastic, though.

I hope this was helpful. I’ll leave you with a bouquet, which I picked just this morning.