Category Archives: Backyard Gardening

A Passive Solar Greenhouse Breathes Life into the Winter Garden

The garden in the quiet of winter is a still and silent place, but its beauty is unfading.  The only discernible sound is the snow crunching underneath your boots and twigs snapping as they brush past you.  Tips of sage leaves and onion shoots hardly peek through layers of snow, only to find themselves buried once again by the fresh dust that falls from the grey sky above.  A squirrel nibbles on remnants unearthed from an aging compost pile.  The garden appears void of life, but its inhabitants sleep quietly underneath blankets of snow, preparing to emerge with new vigor as the season of spring approaches.

A quiet winter stroll down a frost-laden path takes you past tangles of dormant rose beds, twisting branches whose buds have yet to appear.  A simple greenhouse constructed from salvaged wood, metal scraps, and recycled window panes greets you.  Its shabby appearance is hardly inviting, but you sense a feeling of warmth from  within.

Upon prying open a frozen door, you are hit with a rush of warm, humid air, and you find yourself immersed in beds of spicy salad greens, herbs, and mouthwatering tomatoes that hang about from crawling vines.   The warmth of this tiny indoor ecosystem envelopes you, and you slowly breathe in the sweet, earthy aroma of so much life contained within such a small space, with nothing but winter on the other side of the glass.   Invigorating and inviting, this beauty and peacefulness can be achieved with less effort than one might imagine.

This is our vision.  And it no longer seems so unattainable, now that our groundwork is in place.    Construction of our greenhouse is complete… now we need to add a little more love to bring it to life.

The design

We are proud to have constructed this compact little greenhouse, which requires no supplemental heat source other than the sun, from nearly entirely salvaged materials.  The greenhouse measures only 10’ x 12’.

A solid concrete foundation with a depth of 3 feet is further insulated by sheets of insulation under the ground and thick insulation built into the north-facing wall.  Garden beds are built directly into the floor of the greenhouse, keeping the original landscape intact, and with the objective of keeping the ground unfrozen throughout the winter months and providing the most natural habitat possible for the plants.  The floor of the greenhouse is pure soil; this helps maintain the proper growing temperature to simulate outdoor growing conditions.

A strong wood frame built from scrap wood, old windows that were picked up for free from the side of the road, and an old door that was destined for the dumpster form the structural components of the greenhouse.   Ten 55-gallon steel drums, also salvaged, are now filled to the brim with water that is heated by the sun and maintains a consistent temperature- this stored water is the thermal mass that both heats and cools the greenhouse, making the greenhouse self-regulating despite the ever-fluctuating temperatures we experience in Colorado.  The steel drums sit atop a large concrete slab that supports the back wall.   The entire back wall of the greenhouse is insulated with thick insulation, and its many layers keep those little plants toasty on even the coldest of nights.

A thriving worm farm makes its home inside the greenhouse during the winter, and the glorious vemi-compost these worms produce becomes an essential element of our soil when the gardening season begins.

Why it works:

  • Optimum amount of stored water (thermal mass)
  • Colorado’s 300+ days of intense sun
  • Thermal insulation built into back (north-facing) wall & roof
  • Compact design and south-facing windows
  • Plants are planted directly in beds built into floor of greenhouse (directly in soil)
  • Hinged windows provide ventilation when the sunlight is too strong

Dreams of a greenhouse that would produce food year round have finally fallen into place, and we gaze upon this lovely structure that was built with so much love.  We have big plans for this humble little building, and we eagerly anticipate its great potential, knowing that we have taken one step in the right direction toward the more sustainable lifestyle that we yearn for.

This greenhouse has breathed a new kind of life into our winter backyard garden  that we never thought possible.