DIY Indoor Greenhouse for Seed Starting for Organic Gardeners

2012's newborn tomato plants!

One of my earliest decisions in my gardening journey was that I would grow the bulk of my plants from seed rather than buying plants.  It seemed a reasonable choice:  it was certainly cheaper, and I could control what my plants had been exposed to.  I trundled on down to the hardware store and purchased the peat pellets, domed trays, and seeds to accomplish the job.

My first round was a failure--too much humidity after the plants had grown leaves.  So, I chunked those and started again, this time raising a few to put in the ground.  It was that season I realized just how poor my soil was when the plants were stunted and did not produce much.

I tried peat pellets again the next year, with somewhat increased success, but noticed that the pepper plants took forever to germinate.

The "greenhouse"--2012 edition

I tried again the next year, but germinated the seeds in potting soil; they seemed to do better, although the peppers still took forever.

Last year, I decided to "go big" and set up wire shelving with plastic around it, but only one overhead fluorescent light.  The plants germinated, and produced some, but I was still not satisfied.

This year, I'm upping the ante.  Over the year I've invested in a few items for my seedling NICU:

Shop lights
$10.97 each x 3

Fluorescent tubes (one each warm & cool)
$14.24 each x 4

Clear shower curtains
$4.97 each x 3

Shower curtain rings
$4.99 each x 3

Power stick
$9.99

Cost so far
$144.65

The lights are attached as closely as possible to the shelf above.

The 2013 "greenhouse"!

Supporting all of this is salvaged heavy-duty wire shelving (60"x24"x72") which would cost over $300 new.  (Thank goodness the Resident Dragon found them!)

Four shelves are set at 18" intervals.  Each shop light is attached as closely as possible to the shelf above it.  The cords are gently wired to the end of the shelf because the plugs will not thread between the shelf wires.

Around the outside I've attached clear shower curtains to maintain humidity and retain heat.  I've left the bottom shelf empty in case a heater is needed since the "greenhouse" will live in an unheated, attached garage.

One problem I've not worked out is an inexpensive design for seedling heat mats.  Do you have any suggestions?

While the bulk of my planting will be done around Valentine's Day, I'll be starting my early plants in the next week or so.  Check back next week to see the finished greenhouse, and for tips on seed starting!

What's growing in your garden?

Nancy