Photo below - I also used a piece of white marking board to create a door for the long shelf propagation system. Since it was very lightweight and had good light reflecting qualities on the side that was white, I just had to try it. Some small, bent nails are used to keep the bottom and sides in contact with the surface of the shelf, because it's very flimsy - which causes it to bow outward. To open the door, I just rotate each bent nail 180 degrees, then lift the door up. Once up, 2 more nails are used to keep it from falling back down. Very low tech stuff for this construction. I wish everything was this simple!
Photo below - I wanted to show you a closeup pic of one of the homemade temperature sensors. This is type J thermocouple wire, which will sense temperature at the point at which the 2 wires (which are comprised of 2 different metals) are connected. This is the millivolt signal that is sent back to the thermocouple input module of the PLC, and is representative of the temperature value that it is exposed to.
Since these were kinda difficult to see in the video the other day, I wanted to give you a better view of the cellpacks in place. Also, notice that the fluorescent bulb on the far side isn't burning. Due to pretty cold temperatures in the shed right now it takes several minutes to turn on, and is starting to get on my nerves a bit. I don't like it when my stuff doesn't work right, and this light is coming out! It'll be replaced with a couple of t8 fixtures that have electronic ballasts in them, because they have no problems starting under pretty cold conditions. Chalk one up for trial and error, because I wasted alot of time on this light. :-( If indoors, it would have have worked just fine......
I also changed the temperature setpoints for each zone in my plc program, because I found out that a range of 70-75 degrees was actually a little bit too high. 60-65 is more like it, and helps promote a stockier plant stem. In less than 3 weeks, we'll be starting seeds with the wet paper towel method - which is the quickest way for germination to happen, in my opinion.
The temperature trending is working also, and gives me historical measurements every 30 minutes, over a 24 hour period. This will provide valuable information for seeing what goes on inside the systems while I am away. I'll probably go out to the shed each morning before work, just to see if any problems were experienced throughout the night. This is gonna be pretty fun!
Take care, and happy gardening!
EG
11 comments:
Your propagation setup is ready to rock! That is so cool! Especially to be able to review the temperature swings throughout a 24-hour period. In a few weeks you will be growing!
Interesting you mention the problems with fluorescent bulbs in colder temperatures. I am having problems with my new and old fixtures coming on in the basement and couldn't figure out what the heck was happening. I didn't know that cold temperatures affect the ballast until I read it on your blog. It's only 55 degrees down there right now, so that explains it.
Very slick set up EG! The whiteboard definitely makes a good door with the added benefit of light reflecting qualities too. I was out in the shop this evening getting my supplies lined up for the big seed starting efforts scheduled for this coming weekend. Found out I am running low on starter cell packs! (oh the horrors!) I reuse them but periodically a few get damaged and must be tossed ... guess I have had more attrition than I realized!
Have fun with your new system - it really turned out nice.
rachel - as soon as I get the light swapped out, it's on! The historical trending will certainly give valuable info, and very little attention will be necessary for the grow cycle. Most ballasts have a hard time ingiting the bulbs at a temperature less than 60 degrees, and give optimal light at 77.
kitsapFG - thanks! I need more cellpacks, too.
That's a lot of useful data. It reminds me that I wanted to use foil to line my starting set up -- and that I'm going to have to get a new light fixture as two of mine have quit on me (I got some new ones, so I only need one more). It's a good time in the garden!
Hi EJ,
I'm a new follower of your blog (and your garden engineering ideas). Is there any chance you can go into more detail (photos too) of your propogation system? I built one for home use this Winter. It is in my garage. I have several trays going and many seedlings. I am using heat mats, but, I am not happy with the setup. I want to get my oldest Son involved (he is the engineer in the family) to see if we can improve it in regards to regulating heat. Right now, I measure heat, but, I don't know how to regulate the heat mats. I also need to add some reflection so that the plants will receive more of the light.
Also, another question regarding your propagation practice; do you leave the heat mats on all the time? Or do you turn the heat off when the lights are turned off?
You mentioned that you had the idea of introducing automatic watering ... but, decided against it. Just out of curiousity; what were some of your thoughts?
Best regards,
Chris
stefaneener - yeah, the data is gonna be priceless to have.
Chris - First of all, welcome to my blog!
To answer your first question, I don't use heat mats. Instead, I let the warmth of the lights create heat inside the enclosures for me. (Which are fully enclosed) If you can generate heat in yours, just use a thermostat to turn the heat mats off, then a separate thermostat to turn on some ventilation fans when needed.
On automatic watering, I would let a solenoid open up about once per week, and add water to the 1020 flats (without holes) so that the seedlings would be bottom watered.
At this rate, one of these days you won't even have to get out of bed. Just roll over, punch your "grow button", and everything will be automatic. Of course, you'll have a "turn compost" button right next to it ;-)
EG, needless to say, all of us are very impressed. This is a bit more techical than my brain can handle. Haha. So how many transplants do you think it will be able to accommodate?
Granny, well....I could get more sophisticated with it, but that would take all the fun out of it. However....I do have an idea I might implement on my coldframes. Hehe......
Thomas - It's really nothing more than bringing industrial control components into a residential setting. That's all. The one shelf in the picture will hold 210 seedlings, and the other 2 systems will hold 192, collectively.
I think Granny is wrong. You will have it all programmed so you don't even have to press a button. It will all just work on its own.
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