Brownish rings mar the window sills of all my former homes. My cupboards are full of yogurt containers, pudding cups and plastic food boxes. The only south-facing window in the house is marred by scatterings of potting soil, water spills, dried leaves and other seed-starting detritus every Easter. It took 30 years of this to discover I really need a greenhouse.

It was sheer serendipity that my new desert house would be graced with a built-in glass greenhouse along the entire south side. As the seasons passed I discovered just how amazing it was for growing vegetables from seed in the sheltered environment. Now I start all my vegetables in advance without concern for season or space around that one south window. Some of them get potted up more than once as I reserve them for later planting to stagger the yields, something impossible to do indoors.

Today’s greenhouses are amazingly affordable due to space age materials and textiles. These are often sold in DIY kits for easy shipping that require on-site assembly. On the high end of the spectrum are attractive glass and metal structures for thousands that look great within the larger landscape and double as outdoor living spaces. On the low end are small units called “hobby greenhouses,” ideally suited for one person to starting seedlings at very small homesites.

To browse the entire greenhouse marketplace, log on to greenhousemegastore.com. The site gives you an overview of nearly all makes and models on the market today with comparative prices. This site also carries large hoop greenhouses used by commercial farmers and growers that are valuable problem solvers for difficult climates too hot or too cold or too dry for traditional outdoor cultivation.

Whether your greenhouse is large or small, consider where you’ll put it using these considerations:

1. Exposure

Locate the greenhouse in a part of the yard that offers optimal southern exposure. Anyplace on the south side of the house where sunlight is not restricted by trees or other structures will be perfect. The south side offers the most hours of daylight during the winter months and also protects the greenhouse itself.

2. Wind

When greenhouses are covered with sheet material, beware of high wind locations that perpetually tug at sheeting for long periods, loosening its anchors. Windy sites may benefit from rigid polycarbonate panels that are far more solidly anchored, or glass.

3. Water

A water supply at the greenhouse means you’ll have a convenient way to water your plants and seed beds. It also allows you to set up an interior drip or spray system to water your seedlings on a timer each day while you’re busy or at work. An even watering schedule is key to successful healthy seedlings.

4. Floor

The best kind of floor for your greenhouse is gravel on hard packed soil so water that drains from the plants filters down into the soil naturally. This method also reduces costs by eliminating the need for a concrete or wood floor.

A greenhouse is the perfect environment for propagation by cuttings, dividing houseplants, potting and transplanting. Use it to bring your potted vegetables inside at the end of the season to finish ripening late peppers and tomatoes. The ability to store pots and supplies at your fingertips, to set up an easy bench for repotting and propagation turns a simple greenhouse into a plant starting laboratory.

The ease of shipping smaller greenhouses makes this an exceptional holiday gift for individuals and families who are venturing into the food gardening world. It makes starting plants faster and easier so you get dozens of each variety to ensure yields large enough for canning. After my experience, I know any gardener would be thrilled with a greenhouse that, like mine, transforms a backyard garden into an organic food growing machine.