To Build a Window Greenhouse


Well-Known Member
People that live in northern climates has a shorter growing season but their summer is not a heat furnace like southern states get.

This thread is to show habitat people how to build / create a window greenhouse.

You must have a south facing window. You must be inside a heated room. You just have to get your thinking cap working to your advantage.

Window Greenhouse Setup.jpg

The photo above has the window greenhouse positioned in front of a white door so we can see things. In a real use situation this TV Tray is placed in front of a south facing window because it has the best sunlight. If you had a double framed window you could make two trays work.

What do we have?
1. TV Tray
2. Bath Towel
3. Rootmaker 18 Express Tray with Growing Media
4. Two Chicken Lights used to keep chicks warm
5. Two wood risers for holding the lights with one cross piece of wood to stabilize the entire system
6. Two strong plastic clamps not shown in this photo - one at the bottom of each wood riser
7. A 24 Hour Timer with 30 minute individual switches - every 30 minutes can be off or can be on (48 decisions on lights) I run 14 on and 10 off and then when growth has slowed down 12 on 12 off.
8. The timer takes two electrical connections - one per light
9. Add in a few screws, eye hooks, paper clips, bread twist ties

I want the sunlight and I want the chicken lights.

Depending on wall plug locations in relationship to the window, might add one extension cord.
The advantage of this setup is it will not break the bank. Additionally, the weather outside don't put us at risk, we are in a heated room.

I can start this in winter. This makes 18 seedlings possible. What do plants cost when we buy them from a nursery, garden center, or have them shipped?

If anyone reading this thread wonders if they can grow a seedling, this is the least expensive way to jump in the game.

I buy my timers at Walmart and Lowes. I want a 48 decision timer and I want two plugs controlled by this timer.

24 Hour Timer With 30 minute switches.jpg

Sorry for a poor photo. I hope you get the idea.
The clamps I use are strong plastic clamps. This are less expensive and do a great job in this situation.

One Clamp 4 Wood Riser.jpg

One clamp per wood riser. These were not visible in the first photo. They were hidden from view by the rootmaker 18 tray.
Humor helps tree guys and those that wish they could be a tree guy. ;)

I have gotten many inquires about how can I grow when I don't have much room. I have only use two windows in the past when I ran out of room elsewhere.

Happy Thanksgiving to you and yours. I will be traveling to Ohio this coming Sunday for their Shotgun Season that opens Monday AM. :rolleyes:

Hope this thread is useful to you. I did get an opportunity to direct a first time grower to this thread just last week.

I only use chicken lights when all my other growing setups are completely full.

Comments are welcome whether positive or negative. Any have any questions?
So you are using the heat from the chicken lights to warm the soil to spur germination I assume? I have heard most folks want heat from under the tray - is that not really needed? I have grown seedlings from acorns in plastic trays before, but that was outside (I just had to put some wire mesh over them to keep the squirrels form stealing my acorns!).
J Bird,

Two of my window greenhouses are over a floor vent for the central unit. This helps with the heat from the bottom.

I don't run heat lamps in my chicken lights - I use LED lights. These are a supplement to the winter sunlight. I have not started any in the window yet. Got some other irons in the fire at the current time. I have 14 trays + 60 burs in three separate tubs.

Hope this response helps clear up the location of the heat.
Oh - OK - my mistake. So then this is going to maybe be a dumb question......but do LED generate usable light for plant growth? I figured you would need an actual "grow lamp" to do that. You know, like the ones my uncle used when growing "tomatoes" in the closet when I was a kid!:eek: Yep - no lie!!! I also guess I would fear the plant would dry out sitting over your heat vent like that. Dry moving air can really zap moisture out of things, but I can see where it would provide that "lower" heat as well, just have to stay on top of the watering.
A person growing chestnuts will check them every day. When you do that you are going to water when dry. One day dry does not hurt a chestnut.