DIY Indoor Greenhouse

Our DIY indoor greenhouse is made completely from scrap wood.  It serves several purposes in our life during the end of winter and throughout spring.  It can hold more than 200 seedlings that will later go into our gardens. Its lights gives us a tropical boost when winter can’t seem to let go of Eastern Montana and it protects our seedlings from marauding house cats.  At the end of the season it breaks down to store flat.

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Way back when we lived in an apartment and before I ever hammered together the boards for my first raised garden, I got some herb seeds and started them in pots in the window.  I was hooked-I have started at least some of the plants we raise every year.  The first year that we had a cat living in the house, she jumped up and dumped all the pots onto the floor and played in the dirt.

Cameron quietly went out to the garage and it wasn’t long before he was calling for help to carry in his solution.  Because it is made of scrap wood, the only cost is in the screws, the lights and the plastic that covers the front and the back.

Start at the Bottom

Throughout the setting up process, current house cat, Princess Poppy supervised

Over the years, there have been many modifications to our greenhouse.  We put screening on both ends to allow air flow.  One end has shelf supports and 2 small shelves so a small window fan can provide air flow.

We now have laminate flooring throughout our house.  Leftover pieces of padding or door mats keep the wood from scraping the floor.  There are openings in the front for access to the shelves but not in the back so the greenhouse can sit against a wall or not.

Our greenhouse usually sits in the dining room because there is enough space there but sometimes it has been in the living room, the garage or an extra bedroom.  It doesn’t seem to matter whether there is additional lighting in the room as long as the lights in the greenhouse are on for 12-14 hours per day.  In front of a window was a bad idea.  The concentrated sunlight was too much for the seedlings.

Fastening the Base Together

We put the base together first. It is easiest if someone else steadies the end piece

The end pieces don’t come apart at the end of each season.  I have a better picture later but they are built like a frame with the screen permanently stapled on.  There are notches cut out of the sides in 2 places for the 1″x2″ board to form the frame.

We use Jiffy trays to start our seedlings.  The end pieces are 22″ wide so that the trays can slide onto the shelves lengthwise.  We can fit 4 trays on each shelf that way and still remove each tray.

There is a 1″x4″ strip on the inside of the end pieces at each place for a shelf.  It forms a lip that along with the 1″x4″ along the side hold the shelf in place.

In order to make this something we can put together each year, we have extensively labeled each piece.  They say things like “bottom rear” and “middle front” or “top middle”.  Essentially, the directions are all on the parts themselves.  The screws go in a ziploc bag every year so that everything is kept together.

The Shelves on Our DIY Indoor Greenhouse

Poppy is really taking her supervisor job seriously.

Now with the edge piece in place the bottom shelves can go on.  Some of the shelves have small gaps in them.  None of the boards to make the shelves are the same width so the gaps are to make them fill the shelf width space.  They are made out of scrap wood, don’t forget, so we found what we needed that was the right length (or longer and Cameron cut it).  Notice how nothing sticks out over the edge of the frame.  That is how the plastic sheeting can close it all in.

A little note about the keeping the soil warm.  We noticed when we set up in the garage one year, that the plants on the bottom shelf didn’t germinate as fast.  It is too cold out there.  Years ago, we installed radiant heat so our floors are warm.  That really makes a difference on the bottom shelf.  The other shelves each have a shop light under them to light the shelf below.  The little bit of warmth that provides seems to be enough along with the comfortable temperature in the house to germinate the seeds quickly.  If I were to set up in the garage again I would use heated mats but we haven’t needed them in the house.

The Middle Shelf of Our DIY Indoor Greenhouse

We set up our greenhouse where there is space and then slide into an out of the way place.

As you can see…Poppy is still taking this foreman gig pretty seriously.  Here we are onto the middle shelf.  The edge supports and the shelves are in place.

This is also a better shot of the end pieces.  There are 3 pieces of screening fastened to the inside of each end piece.  The bottom edge of each piece of screen comes to the top edge of the 1″x4″ board that holds up a shelf.  The small opening is where the cord from the light goes through.

Screwed to the bottom of this middle shelf is a shop light fixture.  It is important to think about where the outlets are in relation to the greenhouse.  We send all our cords out the same end and plug them all into one power strip so we can turn on and off all the lights with one button.  That is also the end that the outside shelves are on for the electric fans.  Everything goes in one power strip that way.

The Lights and Plastic Sheeting

Once the greenhouse is set up, plastic sheeting covers the front and back

What I was trying to show was the shop light under the shelf. The cat tail just showed up

These GE Plant and Aquarium bulbs fit in the shop light fixtures in our greenhouse. Check them out on Amazon

The view from the business end of the greenhouse. The shelves and cords are all on this end.

The 5 mil plastic sheeting is attached using a staple gun.  At the end of every season we pull the staples and fold up the sheeting.  The back of the greenhouse is done in two strips and stapled so they overlap.  The front of the greenhouse is designed so that the plastic forms a drop-down door for each shelf.

The space between shelves makes a window.  The plastic has been measured so that it can be stapled to a shelf support on the bottom and still covers most of a window.  The top of each plastic sheet is permanently stapled to a strip of wood that has a hole drilled in each end.  The holes fit over the head of a screw that goes only partway into the wood near the top of the window so that when the wood strip is lifted off the screws the plastic door drops down and hangs out of the way while the plants inside are being tended.

We use plant and aquarium bulbs in the shop light fixtures in the greenhouse.  They provide fake sunlight for the plants (and the people).  At the end of the season, we take the bulbs out of the fixtures and store them in tubes so they last for many years.  The bulbs, the shop light fixtures, and the plastic sheeting are all available through Amazon.

What Form Will Your Indoor Greenhouse Take?

Our DIY indoor greenhouse happily doing its job

Year after year, our greenhouse is a fantastic addition to our gardening adventures.  It saves us hundreds of dollars in plants every year.  Our variety of vegetables, herbs, and flowers is so much larger than it used to be.  We are able to try so many different plants every year.  We even use it to give a boost to houseplants that are tired of living with no sunlight all winter.

Is this something that would work at your home?  How could you do something to boost your gardening budget or try new plants?  I have seen indoor greenhouses built from old bookcases or metal shelving.

Drop us a comment, we would love to hear about your indoor gardening adventures as well.