Small Greenhouses for Small Farms: Grow More, Start Earlier and Extend Your Income

greenhouse on railsSmall greenhouses are a pure magic money machine for the small grower

You do not need an expensive commercial greenhouse. A simple, well-built structure can produce thousands of dollars’ worth of transplants, protect valuable crops, and add months to your growing season.

I'm a big fan of small greenhouses. The best money I've ever invested on my farm has been to build my little lean-to greenhouse and the somewhat larger mobile greenhouse on rails shown above (inspired by Eliot Coleman.)

My greenhouses have more than paid me back for the time and money I spent in constructing them. In my opinion, this is one of the first tasks a small farm should undertake.

Quick Answer: Is a Small Greenhouse Worth It?

For most small farms and serious gardeners, yes.

A small greenhouse can help us:

  • Start our own vegetable and herb transplants.
  • Harvest earlier in spring and later in fall.
  • Protect valuable crops from frost, heavy rain and wind.
  • Grow more food without adding more land.
  • Produce extra plants for sale.
  • Reduce the risk of losing a planting to bad weather.

The best first greenhouse is usually not the biggest one we can afford. It is the smallest practical structure that solves a specific problem.

That might mean starting seedlings, growing early greens, protecting tomatoes or adding a few extra weeks to the harvest season.

A greenhouse does not need to be fancy, fully automated or expensive to earn its keep. It simply needs to be well located, properly ventilated and used for crops that benefit from the protection.

Need practical plans? See the three inexpensive greenhouse designs in Bootstrap Greenhouse →

Why Small Greenhouses Make Sense

Here's why building a greenhouse is a great investment for a small farm.

Small greenhouses are productive.
Even my little lean-to greenhouse (about 160 square feet) produces thousands of dollars worth of transplants each season. The production per square foot would probably be in the range of $15-20 or more, if I calculated the value of the transplants the greenhouse produces.

Small greenhouses are cheap to build.
A light frame (of wood, steel or PVC) covered with poly is the cheapest covered space you can create. Depending on your resourcefulness, they can cost you a couple bucks per square foot, or even less.

Our little lean-to greenhouse covers only about 160 square feet, but it has produced thousands of dollars’ worth of transplants in a season. When I built it, my cash cost was about $1.50 per square foot because I bartered for the steel hoops and sourced the remaining materials carefully. You may not duplicate that price today, but the lesson still applies.

A greenhouse does not need to be large, fancy or fully automated to pay its way.

Small greenhouses are easy to manage.
My greenhouses don't require complicated and expensive heating, ventilation or irrigation systems. I water the greenhouses with a hose and sprinkler. Since I operate my greenhouses seasonally (the big one from March to November, the little one from April to October), I don't need a lot of extra heat.

lean-to greenhouseMy lean-to, the first of three small greenhouses I built

If frost threatens my lean-to greenhouse, I just stick in a small portable electric heater. The lean-to greenhouse is ventilated with a cheap box fan ($25) that I turn on in the morning, and turn off at night.

See also my new page  Build a Lean-To Greenhouse to start your plants and keep them thriving. Instructions to build a lean-to just like the one in the picture, the first one I built at New Terra Farm.

Which Greenhouse Is Right for You?

The best greenhouse is not necessarily the biggest or most expensive. It is the one that fits your space, budget and main growing goal.

Greenhouse Type Best For Main Advantage Watch For
Lean-to greenhouse Seed starting and transplant production Uses an existing wall and requires relatively little space Needs a suitable sunny wall and good drainage
Small hoop house Market crops and season extension Provides plenty of protected growing space for the money Must be securely anchored and properly ventilated
Movable greenhouse Protecting several crops at different times of year Lets one structure serve more than one growing area Requires rails, skids or another dependable moving system
Cattle-panel greenhouse Backyard growers and very small farms Inexpensive, compact and fairly quick to build Offers limited headroom and growing space
Purchased hoop-house kit Growers who want fewer construction decisions Includes specialized hardware, fittings and instructions Costs more upfront than sourcing every part yourself

Small Greenhouses Come in all Shapes and Sizes

Turn your imagination loose; a greenhouse can be constructed in lots of ways. One of my gardening neighbours used a fast-framing kit intended to make a small shed to build her little greenhouse. The plastic and 2x2's cost her less than $50.

My farm helpers from a couple years ago (they now operate their own market garden) scrounged a used garage shelter kit. They covered it with clear poly, and now have a very productive 10 x 20 greenhouse. They used pool noodles wrapped around the piping to protect the greenhouse plastic, so it's pretty colorful, too.

If you are keen to build your own hoop house, see my review of my top choice for a DIY hoop house kit here.

Use their kit and your locally-sourced lumber and fence rail to build a hoop house on the cheap.

small hoophouse2019- I built this little 8'x12' beauty using 16-foot cattle panel sections

What Should You Grow in a Small Greenhouse?

The answer depends on what you need the greenhouse to accomplish.

For seed starting: onions, beets, tomatoes, peppers, brassicas, and lettuce.

For early and late harvests: spinach, salad mix, radishes, turnips, green onions, kale and Asian greens.

For warm-season production: tomatoes, cucumbers, peppers and eggplants.

For extra farm income: vegetable transplants, herb plants, hanging baskets and high-value protected crops.

Key: greenhouse space is valuable. Reserve it for plants that benefit enough from the protection to justify occupying that space.

Best Reason: Small Greenhouses are Just Plain fun!

I've been doing this for a while, but I still find greenhouses to be magical. On a bright and sunny day last February, with a couple feet of snow on the ground, I started working in my mobile greenhouse.

The indoor temperature was about 18C (65F). I was working in just a sweater and jeans, and it was thoroughly enjoyable. It was like being transported about 3 climatic zones south without having to eat airplane food (and I didn't lose my luggage.)

small greenhouse in FebruaryStill about 2 feet of snow on the ground, but my greenhouse on rails is ready to go

More like Small Greenhouses . . .

Next Steps

Extend Your Growing Season—and Make Better Use of It

A greenhouse gives you more protected growing space. A year-round harvest plan shows you what to plant, when to plant it, and how to keep the harvest coming.

Build the Growing Space

Bootstrap Greenhouse

Build a practical greenhouse without spending thousands of dollars—or needing professional carpentry skills.

  • Plans for three proven greenhouse designs
  • Step-by-step building instructions
  • Advice on sites, materials, and costs
  • Guidance for making better use of the space

Three greenhouse designs for just $9

Plan the Harvest

The 52-Week Harvest

Create a practical planting and harvest schedule that makes better use of every season—without relying on a heated greenhouse.

  • Plan crops across four seasonal zones
  • Reverse-plan planting from harvest dates
  • Use tunnels and covers more effectively
  • Includes eight practical planning worksheets

Complete guide and worksheets for just $9

Build the protected space, plan the seasons, or get both guides together and a whole lot more in the Homesteader Book Bundle .

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