I have been working on a greenhouse design. The greenhouse in the photos below is not the actual greenhouse. It is the prototype I set up to help me figure out the automation systems and climate stuff. The real greenhouse will be built from what works on this model, and will probably be online in the Fall 2014. This project actually started this fall and now that it’s pre-Spring, I am moving into the second phase: connectivity and control.
Phase 1 was setting up a greenhouse prototype, and then attempting to keep most of last summer’s crops alive through the winter. Since I did very little greenhouse research before setting up the initial structure, I was just winging it out of the gate. I purchased a Harbor Freight off-the-shelf DIY just to get the project rolling.
It took awhile to set up by myself, but it’s do-able. Drink some beer or something. Put on some music.
Although it comes in 5000 pieces, once it’s all fastened together and mounted to the base you build – I used treated 2x10s that I leveled right on the ground vs. pouring a concrete slab which the instructions recommend (lol) – it becomes surprisingly rigid and sturdy. I backfilled it with the white marble chips and concrete pavers to give it a nice, semi-design look.
The winter was going to be a tough one; I knew that going in. Nights in Denver, Colorado were going to get down to -10° F or more and sometimes last for short bursts of up to a week of sub-zero cold. I didn’t spend 5 min. with a calculator trying to determine what my heat requirements would be, humidity, etc. I just built the thing and designed from the hip going forward.
Yeah the thermometer is reading 120° but that is just because the sun is directly beating on it. It’s more like, 85° inside.
The sun obviously played a major role in heating the greenhouse daily. Almost too much.
The big dumb thermometer is just a cheap, Lowe’s thing that I hung in there so that I could see it from the house. Rough but it tells me if the surface temperature of that South-facing wall is either too hot or, more importantly, too cold.
For more accurate internal temperatures, I used what I already had available:
This sensor is old. It’s been hanging outside for 3 or 4 years. And it works in really harsh conditions. So that was the model for any connected sensor stack I want to build that would replace this. This thing is great for one-way broadcasts of temp and humidity. It sends the data to a base unit weather station thing I have sitting in my studio.
What I Learned:
1). Heat rises. You have to heat the greenhouse from a low trajectory. If the heater is mounted too high, and you don’t address the ground-level temperature, you’ll screw up. Don’t let roots or pots freeze. The initial heater I had in there was mounted too high. The super-cooled air at the ground level kept the warm air trapped above the cold air that blanketed the plants that were sitting directly on the ground. The plants hate that. The roots froze. I really felt horrible about that. I added a second heater to keep the ground-level warm. About a week later, I lost several more plants because of a tripped GFCI outlet one night. When it shut down, the sub-zero weather in Denver quickly dropped the interior temperature below freezing in probably less than an hour. My failure to provide a fail-safe backup heating system or even a notification SMS or alarm was stupid. Honestly, I had not set out to make this greenhouse a “Project” project. It was a hastily constructed mock-up and, even though I considered blown fuses or power outages, I neglected to consider the fact that I would be asleep when it happened.
I added a second heater: one on the ground level and one at mid-level.
2) Humidity must be controlled. Some days, the humidity would stay in the 50 – 75% range. Even higher after watering and snow. Weird shit started to grow. Stuff like fungus and molds. Humidity is evil. Another pest that moved in: these spider-mite entities:
These were covering two, good-sized rose bushes. I’d venture to say “billions” but who was going to count?
Started wiping them out with this:
After treating, a lot of leaves just fell off. I hope they’re going to come back this summer. Shit.
The winter damage was palpable.
The concrete balls fared well.
These are tough plants:
Cleaning up and getting prepped for Spring.
Pulled out dead stuff and washed it down:
Started to reorganize it.
Before moving to Phase 2, I wanted a live video monitor to watch inside. I threw a Dropcam in there and got it live on the network. This picture makes me look fat.
What Dropcam “sees” at night:
Once I had run it through a Colorado winter, I now knew what kinds of environmental variables I needed to design for. I moved back into the lab to start laying out the overall concept. I want to scale up the entire greenhouse idea for next winter. I need a control system that allows me to monitor and respond to environmental changes. The primary goal: keep stuff alive and healthy through variable Colorado winters. Back up systems and all that. And I want to collect data. Lots of data. Why? I don’t know… shut up. Here’s my dev setup:
Below, a closer look at the initial components. The accordion things are packaging prototypes that are used for protecting the hardware from humidity and splashing water. You’ll see those again down the road. There are all the usual culprits: Arduino, Raspberry Pi, XBee, some TI Sensor Tags… blah blah blah. Mostly just thinking about what makes sense to build on.
Right now, it’s in the architectural design phase. I need to decide on some technical details and platform-based options. This is really an experiment first and foremost. I’m not entering the “Greenhouse Control” business. I just want to make my greenhouse super cool.
Anyway, I began by setting up basic connections and sampling the data. Below, I am running a test on the Bluetooth data that is being sent by the TI Sensor Tags. Usable? We’ll see…
I’ve been doing a ton of online research around other projects that have addressed this similar problem and there is a lot out there. I probably can make a post and list links to all the stuff I have found along the way. Some are very sophisticated systems.
So that’s the Mayfair Greenhouse introduction. I’ll check in later.