Friday, April 10, 2020

Midwest Gardening April: Greenhouse Heating

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First week of April 2020 Midwest Gardening.

While so many of you are in zones far warmer than Chicagoland (5b) we still battle crazy temperature changes. 

We had a few days of really nice weather last week. This shows the wall temp(in the sun) roughly at noon. No need for a heater then.

At this point, we open all the windows and turn on the ceiling fan. These planters are under a shelf---and it's 91.9 degrees F.

We moved almost all the plants from the kitchen out to the greenhouse early last week.

I also started large planters of lettuce are on the floor on the west side. We have used paver base as a floor, it's fine for walking on and will absorb excess water. We are waiting to see how the drainage, heat, and comfort works with this. We may put some patio blocks over this--
for holding heat in the Fall. 

I am going to try and keep the greenhouse 
going for fresh greens and vegetables until December...we will see. 

We should have purchased a heater in winter, because, now, Hubby didn't have much of a choice. 
We had wanted one with a temperature gauged on/off switch, but none seemed available. 
We ended up with  a 2 ceramic rod 1500W heater, choice of 1-2 rods on, 
and a wide temperature range dial.

How much electricity you use is dependent on the settings. We usually turn it totally off by10am on any kind of sunny day, and quite low on cloudy days. Even during clouds you have radiant heat penetrating through.

Excuse all the cords (12guage for the heater) everywhere. Not going for aesthetics, yet in the greenhouse.

The other purchase was a remote temperature system, which came with three sensors (battery) which transmit to a display screen in the house. We can see all three temps-most of the time, as they cycle at different times. 

In the afternoon the sun can still be quite hot---however, once the trees leaf out it should be easier to control.

These gauges  are very sensitive to we don't get hysterical unless all three temps register insane numbers.
The manual ceiling fan (3 settings) circulates the heat and also makes our plants stronger.

This is the indoor display...96, 72, 98...we know that two sensors are in the sun at this time. The bottom 74 is our home indoor temp(lots of windows in this house) and 48 is the humidity. 

Last night was 27...degrees, and we maintained in the 40's with the 2 rods going at about 75%.

Now, I will go out and turn them way down, though the outdoor temp is still in the 30's as the sun is kicking in. (9:30am)

We found, prices range for heaters, $50-$200, ours was $79. 
Prices for sensor systems are basically under $100 + the price of batteries. Lots are available with many options.

I'll never advertise any brands or systems, just giving you an idea of how much this little project ends up costing. These are multi-season investments. Our last greenhouse lasted us over 10 years, this one should be good until we are gone. We did burn up 2 heaters in the last 10 years---because of moisture issues, but the last greenhouse was a tent of sorts, this one is pretty much waterproof.
AND, that's why cords are strung up all over. 


Thank you for any and all comments.
Finally I am able to reply to comments by using Chrome. So all you Mac users who have upgraded to Catalina---this might help the glitches on Safari  and Blogger!


  1. Lots of work... but I am sure you will have a beautiful garden! I am waiting for seeing it!Happy Easter !

    1. Aw, thank you Maristella, right now, I would go for your sunny porch! We have snow forecasted tomorrow..not much, but low temps. Hugs, Sandi

  2. It must have been exciting to move all your seedlings to the greenhouse and to free up space in the kitchen. I'm going to text a link of this post to our daughter-in-law who built her first greenhouse last fall. I think her monthly electric bill shot up dramatically all winter so maybe she'll find your heating information helpful to her.

    In your previous post--wow, you both have accomplished so much to make your dungeon more usable! And done a ton of work in the process! I have a friend who has been taking clay pottery classes this last year and loves it so much. Your business during that time sounds fascinating. I have a feeling that whatever interest you're involved in that you are passionate about it and give your all to it. And I hope you get good gardening weather there soon!

    1. Thanks so much Dewena, if your d-in-law works there are heaters/and sensors that will turn them on and off. So far, since we are home and can watch it religiously---we can adjust the heaters and the cooling fan. When the sun comes out, it can get hot---fast. Thanks on the dungeon...I hesitated to share, but somewhere down the road, it may be more attractive. I have a strong belief in reality! Grins, and thanks for stopping by. Sandi===ps its going to flurry here tomorrow, LOL.


Thank you for any and all comments. I will be happy to answer any questions or comments in replies or email! HUGS!