Building the Greenhouse’s Guts, Part 2: It’s Hotter Than Balls in There!

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The greenhouse is nearing completion.. FINALLY! (See the first part of building the greenhouse’s guts here) However, we are noticing one major issue. It’s hotter than balls in there! The problem is that our greenhouse comes equipped with “automatic” window openers. Basically, these things are little black pistons filled with a paraffin wax. When the wax gets hot, it expands, pushes out the piston and opens up the window.

automatic window openers for the greenhouse
Here’s one of the four “automatic” window openers we have in the greenhouse. Heat thieves.

Pretty cool, right? It is cool… but it didn’t quite work the way we needed. The problem was the wax begins expanding at about 70-75 degrees, which is about the temperature we want to keep the greenhouse at. So, what had happn’d was…our radiant heat floor would get the greenhouse up to a perfect 75 degrees. When this would happen, the windows would open and let out all our nice, perfectly warm air like a bunch of little heat thieves. And then, the pump would have to kick on again to heat the floor up. And round and round we’d go. On top of that, solar heat from the sun would get the greenhouse SUUUPER hot some days. Like 115 degrees hot.  Those little wax pistons just couldn’t cut the mustard. The temperature swings we would get in Missouri during the fall and spring are just too drastic. It can be freezing at night and 55 degrees during the day sometimes.

This was also hell on our little home thermostat that controls the radiant heat water pump. When the windows would open the hot air would escape and the thermostat would kick on the hot water pump in the floor on and heat up the greenhouse. However, the floor was already hot enough to keep the room at the right temperature if the damn windows would just stay closed. Also in general, home thermostats are great for controlling the air temperature in a well-insulated home, keeping humans comfy. However, for controlling the air temperature in a not-so-insulated greenhouse, keeping plants comfy… not so much. It’s just not made for it. We need a solution. There are motorized window openers out there but we need to be able to control them based on want we want, not how wax feels like expanding.

The home thermostat.
The home thermostat.
Less than ideal readings due to our 3 way tug-of-war system
Less than ideal readings due to our 3 way tug-of-war system

In the end, we decided that our problems was that we really had three systems going at once. 1) The automatic window openers, opening and closing the windows trying to cool things off, 2) The thermostat, which controls the pump that circulates hot water through the floor trying to heat things up, and 3) Us, trying to adjust everything to make it work reliably under different weather conditions. Basically three systems fighting against each other instead of working together.

After much research, we decided what we needed was a central computer that can control all these systems based upon the readings it gets from sensors and how we program it. There are many different types of greenhouse climate control computers out there and they all have one thing in common. They are all REALLY friggin’ expensive. Dave was not down to spend a big pile of cash on the greenhouse’s brain. But something had to be done. We could just control everything by hand, but that takes FOREVER. We got stuff to do! Dave and Nemo looked into building a computer themselves out of adrino boards. But having never built anything with adrino boards before, they didn’t want to teach themselves by building a crucial part of our farm business. Also with the the planting season right around the corner the didn’t have the time to do it, much less learn it. What to do, what to do?

Enter, our savior from the north ERIC LABBATE!!!

First, we want to say that Eric is the MAN! He’s a pioneer in this field. Eric founded a company called Climate Control Systems. He was the first person to bring computer controlled greenhouse technology to North America (Lemington, Canada) from the Netherlands 30 years ago. Most of the systems Eric designs are for MASSIVE greenhouses. We’re talking 10 acres under glass. So our little 300 sq ft greenhouse is small potatoes compared to the greenhouses he usually works with.

Greenhousees in Leamington, ON. (via

Basically, Eric is kind of big deal! Prior to Eric’s developments, a greenhouse tomato plant was producing about 16lbs of fruit per plant. Today, a greenhouse tomato plant can produce up to 60lb of fruit per plant. Now, Eric himself has said this is not all due to climate control…but a lot is, and he’s very modest and humble guy.

Zach had been spending a lot of time researching different companies that build and design climate control computers. He talked to many of the companies out there. Out of them all, Eric’s climate control systems seemed to be the best and have the best reputation. Also, Eric was the most helpful in assisting us in identifying our exact problem, and coming up with a feasible solution.  Eric offered to sell us an older units he had in stock from Growmaster for HELLA cheap. Like 1/3 of the retail price! He also built us a relay cabinet and threw in a bunch of sensors and a transformer on the SUPER cheap too. This computer will not only solve our heating and cooling issues, but can be expanded to control other zones, humidity, irrigation, lights and all kinds of other stuff in the future if we want! To be honest, there would’ve been no way we could have afforded a Growmaster computer and all the fixings with out Eric’s generosity.

growmaster computer and relay cabinets in greenhouse
On the far right is the Growmaster computer and the other two boxes are the sweet relay cabinets that Eric hooked us up with. ERIC IS KICK ASS!

We had to thank him personally! Since Zach and Gus wanted to take a road trip anyway, and Dave hates paying for shipping….Zach is going to America’s Hat! (Canada)


The journey from DeSoto, MO to America's hat... Canada.
The journey from DeSoto, MO to America’s hat… Canada.

3 Responses

  1. February 26, 2013

    […] UPDATE: Check out “Building The Greenhouse’s Guts, Part 2: It’s Hotter Than Balls in There!” […]

  2. March 7, 2013

    […] means that we are getting daily temperature swings between 55 and 110 degrees in the greenhouse (hotter than balls!).  This is meant to be a spa for plants where they can kick back and relax.  You know…take […]

  3. March 11, 2013

    […] just around the corner (we’re hoping), our interior space sufficiently set-up and our climate control system installed, we were finally ready to put this greenhouse to work! But wait! We were missing one important […]

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