How I Built a Greenhouse from Recycled Windows

Extend your growing season with a greenhouse and start new seedlings earlier in the spring

The first frost in NE Kansas averages around Oct-20. The last frost around Apr-20. That is 6 months of no growing season.

I had setup grow lights in my basement to start plants earlier, but it was starting to take over my basement. It is also the same room as my preps, which I did not want to expose to too much light.

My Goals:

Extend my growing season and have fresh greens later into the fall.
Start seedlings earlier in the spring without depending solely on grow lights.
As I moved into growing tree seedlings with GrowNutTrees.com, I wanted a place to store seedlings over the winter to somewhat reduce heavy freeze damage.
Stretch goal: Grow more tropical plants like Moringa in the summer.

Let’s Build – Recycle and Reuse

My neighbor was throwing out some old storm windows and a door. I bought some additional windows from the Habitat for Humanity ReStore. I recycled as much wood from other projects as possible, with the remainder of the wood and plexi roof panels purchased from the big box hardware store.

Greenhouse — Inside the greenhouse – Black Seeded Simpson lettuce and buckets of hazelnuts

I created a raised bed from 1×8″ pine boards and 4×4″ corner pieces. Filled with a $10 truckload of soil and some compost. Weed fabric and gravel on the floor.

Greenhouse raised bed — Black Seeded Simpson lettuce and kale

You can see Black Seeded Simpson lettuce (which is a cut-and-come-again variety) growing in the raised bed, and buckets of Hazelnut seedlings.

Positive Results – Extend the Growing Season

Greenhouse snow — The greenhouse held up well in the snow and cold

I built the greenhouse in October 2020. A small heater helped on cold nights. I have had greens growing into January and February. I had greens growing until February 2021 when the huge cold snap and snow and ice storms hit – the one that froze the windfarms in Texas and caused power outages.

This Fall I had elderberry and hazelnuts in pots, getting an extra 2 months of root growth. It also gives me an early start on plants.

The greenhouse allowed us to extend the growing season by two months or more, and to start almost two months earlier in spring.

In the summer, it is over 100 degrees in the greenhouse. That is too hot for greens to grow. I planted Dwarf Moringa, which is a leafy tropical plant. Try as I might, I could not get it to grow in the garden. The moringa grew all the way to the ceiling of the greenhouse.

Lessons Learned:

It helps to have a digital thermometer that shows the current temperature and the highest and lowest temperature in the last 24 hours. That way you can see how cold it is getting in the greenhouse at night.

I originally sized the wooden frames for the windows so that the window would fit inside, like in a house. This didn’t work, especially for the large windows (like storm windows) used on the south side. So I ended up narrowing the frames and screwing the windows right onto the wall frame, which worked much better. Unfortunately this fix added more wood to close up the original sized frame that I used. (as you can see in the inside pics above).

The door was longer than my frame, so I cut off the bottom of the door.

Remember – measure twice, cut once. Several more trips to the big box store to get 2x4s because I didn’t follow this rule, or my math was off. Learn from my mistakes.

The original cost was about $600 (but that was before the big rise in building materials in 2020). That price did not include the free bay windows on the south and east side that I got from a neighbor. The cost now would be at least $1000. Building a comparable chicken house in 2022 cost about $1000.

This wasn’t very difficult to build – pretty much like a shed. Try it yourself.

Thriving Food Forest Design: Let us create an edible foodscape, perennial paradise for you so you can grow more food and be more self sufficient. Schedule a free consult session with me at:

Thriving Food Forest Design – Let us create an edible foodscape, a perennial paradise for you so you can grow more food and be more self sufficient.

Raised beds that I am building to test Perennial Kitchen Garden layouts:

Vego Garden Modular Metal Raised Bed (which I will make 5′ x 3.5′, 17″ tall). I use this for a perennial kitchen garden – growing herbs to use daily in the kitchen. Just come along and pick what you need for tonight’s dinner.

Vego Garden Modular Metal Raised Bed – 5′ x 3.5′ x 17″

Meadow Creature Broadfork is my favorite tool for starting new garden beds. I turn over the sod, add a layer of compost, then Milpa, and cover with woodchips.