Greenhouses are very expensive to build but you can put up a small greenhouse in your backyard and have it ready to use in a matter of hours. With the variety of outdoor canopies or outdoor tents on the market you can order one made with clear material with zippered openings. All you have to add are the plants and maybe an inexpensive sprinkling system. You can even get a timer for your sprinkler, cutting your work down even more.
If you are needing a greenhouse that you can put up and take down with ease, consider a smaller outdoor canopy that has a pop-up canopy design.