Introducing The PortablePallet-and-Hoop Greenhouse(my latest bright idea)

Dateline: 6 May 2014

Don't laugh. This is a better idea than it might first appear. I "invented" this portable pallet greenhouse because I bought some of These Deep Cell Plug Trays, and the trays are too big to fit under my amazing solar pyramids (as I've shown with tomato seedlings in This Past Blog Post). 

The portable pallet greenhouse consists of one pallet (measuring 40" x 48") placed on top of my now-old-and-well-worn (but still perfectly functional) Whizbang Garden Cart. The three hoops that support the plastic cover are 5' lengths of 1/2" pvc water pipe. The cover is 6' wide perforated row cover plastic. Recycled cardboard is nailed down over the bottom of the pallet to keep out bottom drafts. A length of Twine is tied tightly around the perimeter of the hooped enclosure. Clothespins hold the plastic to the twine all around. The interior dimensions of the greenhouse are 32" x 45."

If you have my Planet Whizbang Idea Book For Gardeners, you will recognize this set-up as a variation of Mark Albert's remarkable caterpillar cloche sysyem. 

Being portable I can wheel the greenhouse anywhere I want. When located right outside the door to my house (as the picture above shows it) I can easily transport young seedlings into the greenhouse in the morning for a day of sunlight, and bring them back in the house at night (because early spring nights can be too cold for the young plants).

Being raised up makes it very easy to work in the greenhouse. Simply unclip the plastic on one side and the contents are conveniently accessible at waist height.

Being made of an old pallet, recycled cardboard, twine, and other basic materials means this greenhouse is cheap to make. And it is surprisingly sturdy. It has been buffeted by some strong spring winds and, though the plastic flaps around, all is peaceful inside the structure; the plastic cover holds tight.

Another advantage to a portable pallet greenhouse is that you can make it in a few minutes. This is not a complicated, time consuming project. The following pictures provide more details.

click picture for enlarged view

The end of the pvc hoops slip over a short piece of 1/2" wood dowel. I drilled a 5/8" hole through the top board of the pallet and just enough into the bottom board of the pallet to create a pocket for the end of the dowel. Then I cut it off at 1.5" above the top surface. Slide the pvc pipe over the projecting 1.5."

If you space these dowel pins 32" apart, the 5' length of pvc will bend and fit to make a nice hoop that is 21" high.

The above picture shows how the clothespins clip the plastic to the twine all around the bottom of the hoops. This arrangement is much stronger than you might think. 

The above picture, taken through one of the holes in the plastic cover, provides a peek inside the greenhouse (click the picture to see a larger view).

This little portable greenhouse will hold a lot of plants, and we will make use of it through the season. It amounts to a lot of practical functionality without a lot of fuss and expense. The parts can be reused again next year.

This greenhouse is part of my "off-grid" approach to starting plants for the garden. I never use heat mats, or electric lights. They are not necessary for a family-size garden. Plants can be started on a windowsill. They will get a bit "leggy" on the windowsill, but if you re-pot them into a bigger container after the first leaves have formed, then get them outdoors, under plastic, into full sun, as much as possible after that, they will grow just fine. That has been my experience.