Small Greenhouse - convert an unused shed

My small greenhouse had humble beginnings. Below is a picture of how it all started. It's an old shed just the way I was it when I bought my home in the early fall of 2002. With a sagging roof, rotting foundation, dirt floor, and only one window, it wasn't a nice place to spend time. Little did I know that it would become my first homemade greenhouse.

Outbuilding on the left became my small greenhouse after quite a bit of work to strip and rebuild it.

I used the outbuilding as a chicken house for several years, and also stored yard equipment there after I built a separate place for my fowl out behind the barn. At best, it was a cobbled together shop constructed of recycled wood and used for various purposes including raising rabbits. It was a well used, dimly lit space about the size of a single car garage.

Before converting it to a greenhouse, I considered making it a shop, but it was just too small, and it was too nice to waste on chickens. I thought about razing it and starting from scratch, but then I said to myself, "if you're going to have a small greenhouse, why not start with the framework of this little shop?" So, I salvaged what I could and made a nice DIY greenhouse out of it.

The key to making the decision was it's orientation. The length of the building faced south, so it would suck in all of the low southern sun during the winter, and that's just what I wanted...a place to keep cold hardy vegetables during the winter months.

Below is how it looks today, June of 2008 after several weeks of demolition and reconstruction. The work is behind me now, and lots of wonderful vegetables are in my future.

The small greenhouse is finished, a project that required some bracing, painting and lots of demolition.

It turned out to be just the right size and location for a “kitchen greenhouse” where fresh thyme, tomatoes, onions and greens are close at hand. This small greenhouse is also where our eggplant, pole beans, snap peas, snow peas, Swiss chard, spinach, lettuce, cucumbers and a full assortment of herbs reside.

There are still some finishing touches to put in place, but it certainly is a very functional small greenhouse as-is, and a cheap greenhouse at that. It measures roughly 15 feet by 30 feet, and has a 10 foot high roof peak.

Our small greenhouse is 450 square feet, and we wouldn't want it any smaller than that.

I should mention something about the idea behind a small greenhouse. When people think small, most often they're thinking about something like a hobby greenhouse, perhaps the size of a bathroom or a full-size van. That's too small for vegetables and I'll tell you why. By the time you let your plants get to their full size, the space you have left over for walking, relaxing, harvesting and simply enjoying your greenhouse is quite limited.

Even if you're thinking about just a modest size greenhouse, let me suggest that you decide how large you want your growing area, then double that square footage. That's probably a good way to determine a comfortable size for your greenhouse. It might not seem like a small greenhouse to you, but if you don't allow a generous amount of space for you, your tools, your supplies, and some swingin' room to get things done, you'll soon find that the greenhouse you built is just too small indeed.

Below is a picture of the inside of the building with our plants growing as of early June, 2008. This greenhouse provided sufficient protection to allow our snap peas to reach 4 feet high, and we have already had more than a dozen generous bowls of salad from our plantings.

Spring growth in the small greenhouse, mostly provides salad greens.

Below is the same view of our small greenhouse six weeks later. You'll notice a big difference as tomato plants are about 8 feet tall. By this time, we have ripped out the peas and taken out the bolting lettuce plants and fed them to the chickens.

It's amazing how much better plants grow when they are protected by a greenhouse. If you have an unused shed, you might consider building your own small greenhouse and...

get growing!

Summer growth in the small greenhouse provides tomatoes, egg plant, herbs, peppers, onions and beans.

Now, can you see how a smaller structure would have us feeling boxed in? A good rule is if you don't have room to be comfortable, you'll likely spend less time tending your garden, and that tends to defeat the purpose of having a greenhouse in the first place.

Build your greenhouse larger than you think you'll need, and you'll never regret having the extra room. Besides, larger structures cost less per square foot of space.

If you build your own greenhouse out of wood, be aware that you need to sand and paint the wood, and this can be an expense and quite a job. Also, wood can rot in a damp environment, so be aware before you build.

The north wall and a small strip of the north roof have sheathing left in place, but the remainder of the building is covered by woven ripstop poly that does a nice job of letting in light and resisting the harsh weather we have out here on the prairie. If you decide to build a small greenhouse like this, it would be ideal if you had one like this, one where there is electricity and water already installed.

I'm happy that I was able to hold onto a piece of the past on my way toward a more self-reliant future. It's a good way to make better use of an asset instead of having the expense of replacing it. We've harvested plenty of food from this relatively small growing space, and we're never regretted having the amount of room that we do. If anything, we could easily find good use for more room.

To determine the right size for even a small growing space, rope off an area on your driveway or in your backyard and pretend to use the space. Get two people in there using the space and simulate beds and tools and a place to sit, and don't forget a table or bench or sink. Then, after working for a while in the simulated work environment, you'll likely have a much better idea as to what size your greenhouse should be.

Here are details about how I built this small greenhouse if you would like to build your own from a shop, shed or other under-utilized outbuilding. Good luck, whatever you decide to do.

Done with Small Greenhouse, back to Build Your Own Greenhouse

If all you have room for is a small greenhouse, that's fine as I think you'll be surprised at what even a small greenhouse can do for you.

In the event you're looking for more help or suggestions on this topic, here are additional resources that might be of interest to you.