Mini-Greenhouse Upgrade

skrit

Yamadori
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So I semi-promised my next thread would regard the upgrade of my tropical's winter home, so here goes nothing.

A bit of background:
Last year when I was just starting out I encouraged my wife to attend an introductory workshop intended for pairs (mostly couples attended, but two parent/child pairs also attended) in which we received and worked on three trees, two small trees and one larger. My wife was not attracted to junipers and chose two ficus as three of our trees. At the time I don't think either of us really understood what kind of winter care that would entail. I also purchased a small dwarf jade not long afterwards. Unfortunately, our only real southern exposure windows are in our finished basement, and I thought that with 36" windows they would get enough light, so that's where they went. After a couple weeks of ever shorter days and realizing that pine trees at the nearby edge of the property blocked much of the light, I went out and got a 2 bulb 2' T5 fluorescent fixture with appropriate 6500K bulbs to hang over them and supplement the limited sunshine. This seemed to work OK at first, but as cold weather set in, I needed to heat the space to keep them warm, so on went the gas fireplace in there (along with a thermostat) to keep the place around 64F. (a bit colder near the window, but I kept a thermometer there to be sure it stayed above 60F.) Then the collection grew over this summer with the addition of some Schefflera Arboricola. With the new additions, one windowsill wasn't going to cut it, and I didn't want to pay to heat the whole basement just for a window full of plants.

Cut to this year:
I bought a mini-greenhouse with the intention of adding the light I bought last year and another CFL along with eastern exposure through a sliding glass door in our kitchen / dining room. Long story short, light was poor due to the slightly northern angle and insufficient supplemental electrical lighting for the space (CFL was barely sufficient), no air circulation which encouraged some white fuzz type mold growth (only on one plant thankfully) and humidity was highly variable and generally low in the area, probably due to the nearby forced hot air vent. (which as it turns out blew right into the greenhouse!)

Initial pictures of this year's setup attached.
 

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skrit

Yamadori
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Upgrades included the following:
  • A 6 bulb bank of similar 2' T5's, which put out far more light over a much more even area.
  • Relocating the smaller T5 fixture below the upper shelf to provide better light to the lower shelf.
  • Removing the CFL
  • Adding air circulating fans that operate at a very light breeze. (Set in a circular airflow pattern)
  • Reflective white poly around perimeter to reflect scattered light back in (also does a good job of keeping the greenhouse from lighting up the back yard!) and increase thermal insulation. (double thick due to ordering more than was needed) Zippered door has a sheet taped up on the outside of the clear plastic cover with a hole to check the temp/humidity readings.
  • 40 some odd little black zip-ties to keep all the wiring neat.


Possible future upgrades include the addition of a heat mat (like the ones used for seed propagation) to add some small additional heat during the night when the lights are off. Possibly topped with a sheet pan full of water to increase humidity if required.

Pictures attached (please ignore the cat butt in picture 5)

I haven't had this arrangement up and running for long (only about 36 hours), and so far it's pushed my temperatures up to the low to mid 80s and humidity around 70%. Night was lower around 68. Not sure on the final numbers yet but that's a pretty good approximation I think.

To clarify, as I haven't stated it already, the point of this post isn't to show off. I want to know if these are approximately correct numbers for keeping these ficus / sheffs. I have the dwarf jade in there too and know that it likes dryer climates, will it be okay in there? Have I missed anything or done anything obviously wrong? This is my first attempt and as mentioned previously, I'm relatively new to all this. I've certainly never built a greenhouse before and am happy to have any feedback.

I am a bit concerned that condensation appears to be forming on the 'roof' above the light fixture and running down the insides onto the wood floor. I'm going to have to do something about that or I'm going to have a lot of water around. I have a bit of that white plastic left over that I'm going to put down under it in the mean time to protect the floor. Does anyone have a recommendation for preventing the condensation in the first place? I assume it's due to lack of air flow in the area and the relatively poor insulation of the clear plastic / cooler ambient room temps. Perhaps I can fit another fan up there somehow.
 

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skrit

Yamadori
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For anyone that's curious (and perhaps it's explained elsewhere in the forums, the fan setup is essentially 4 computer fans wired to a 12V power adapter. I had some spare network cable laying around to use for conductors that helped keep it neat. Attached photos for condensed description. The only thing to really keep in mind is to add up the fan loads to be sure your adapter can provide the required amperage and be sure to wire in parallel.
 

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Joedes3

Shohin
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Great setup.
I have a question about the fans. I have some trees in my basement, temp always 60+/-, and under shop lights. Should I use fans and why?

Thanks
Joedes3
 

M. Frary

Bonsai Godzilla
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Great setup.
I have a question about the fans. I have some trees in my basement, temp always 60+/-, and under shop lights. Should I use fans and why?

Thanks
Joedes3

Air circulation man. Air circulation.
 

skrit

Yamadori
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Great setup.
I have a question about the fans. I have some trees in my basement, temp always 60+/-, and under shop lights. Should I use fans and why?

Thanks
Joedes3

Fans provide air circulation. Air circulation is good for a few reasons. It prevents lights from overheating plants, causing hot spots or pockets of still air. It circulates fresh air to the plants and stale air away. (This is a bit less applicable in my small enclosure, I open it daily to let in fresh air but air circulation still helps the leaves breath better, or so I understand) Air circulation also helps to prevent mold and fungus growth and insect infestation. Finally, it also encourages your pots to dry out a bit faster. This is good because although you have to water more frequently, it means that the air spaces around the roots get refreshed more frequently (every time you water you force out the old air, and as the plant drains/dries out again new air is introduced).
 

Fedral144

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I used clamping reflectors with single daylight color temperature CFLs when I only had a couple plants. The plants grew better than just sitting in a window. I'm not sure if it would be enough in an office without a window nearby.
 
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