Topic Type:
Question
this would be awesome to open source. I'm wondering how a top-loading freezer would work for the cabinet, though. It would be awkward to shuffle around flats. Seems like something that loads from the front, either salvaged or constructed, would be preferable. This is definitely on my to-do list. A commercial unit can go for $4k, new. Should be able to beat that!
Hey there,
We took a 24 cubic foot chest freezer and stood it on it's end. Removed the springs in the hinges which act as a "lift assist" (they were keeping it from closing), added a hasp to keep it shut, and inserted a welded steel shelf to take 22 flats (11 shelves). I'll be updating the photos today--take a look at how we did it and please feel free to contact us for more information.
I'd also appreciate feedback on this design. I have already realized a number of weaknesses. One of which is that the steel shelf is very difficult to protect from rust in such a wet, warm environment. Also, I should have isolated my galvanized pipe flanges and bolts from the aluminum pan. Will most likely have to replace parts of the system as the galvanic reaction eats away at them. Could also have used stainless for everything. But, whereas the shelf cost around $120 in steel, stainless would have been much more expensive.
Hey Dan - Excellent idea here.
In general, I'm wondering how this design worked for you in reliably germinating seedlings? A few specific questions:
Was the humidity and temperature relatively consistent on the top shelf vs. bottom? Was there any drastic difference in germination times? How has the heating/water system held up over time? (you mention the galvanic reaction above - is it worth going with stainless?) Any other substitutions in materials you would have made in hindsight?
Great post!
Hey Kyle,
I built this for a farm in Shrewsbury, VT so I asked them to answer your questions since they're the one using it now. Answers in-line below:
Was the humidity and temperature relatively consistent on the top shelf vs. bottom? Was there any drastic difference in germination times?
Germination was consistent throughout the chamber...I haven't measured any difference in temperature and humidity from top to bottom, but on a practical level it works great.
How has the heating/water system held up over time? (you mention the galvanic reaction above - is it worth going with stainless?)
It's only been in use for a year, but there haven't been any issues with the materials.
Any other substitutions in materials you would have made in hindsight?
I'm happy with the materials. Some things we learned are that its necessary to cover the seeds more than if they were going to naturally germinate...the high humidity environment can cause the plants to send their roots into the air, rather than the soil. We're going to experiment by partially covering the top of the water reservoir to keep the humidity below 100%. It's also imperative to remove the trays just before germination...in the completely dark environment we've had trays with no sign of germination one evening, and the next morning the cotyledons are over an inch off of the soil on a thin leggy stem.