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Can greenhouse be too big?

Discussion in 'Growing Areas' started by DanielG, Aug 12, 2017.

  1. DanielG

    DanielG New Member

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    I am planning for a new GH within a year or so. I grow mainly miniature botanicals on mounts, as a serious hobby, no gardener/care-taker. Is it possible to have a GH that is too big? Standard answer is "no", but I think there is a difference between a collection of Grammatophyllums and a collection of Platystele. Pots in single level shelves is different from hanging racks with multiple levels. Given that a GH makes its climate in part by it being filled with plants, an empty GH is not helpful to the plants either.

    Given my preferred plant size/type, what do you think is the most a single person can handle in terms of number of plants and/or square footage? Currently I have around 2-300 plants, pretty crammed, and that is certainly doable. 500-1000 plants sounds about like the top end. I am thinking of 300-500 sqft, with a potting/mounting station inside. I wonder whether even 500 is too big and 300 might already be generous.

    Any words of wisdom?
     
  2. Ray

    Ray Orchid Iconoclast Supporting Member

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    I think there are many factors to consider in that decision:
    • How much time are you able to dedicate to plant care?
    • How automated will the control systems be?
    • Can you afford the utilities?
    • A larger structure will be more stable in its conditions.
    • Your control systems dictate the environment far more than do the plants.
    • A larger structure may allow you to have "climate zones".
    • Growing plants spaced apart is better than bunching them up.
    • Equipment (heaters, fans, RO systems, tanks, pumps, etc.) take up space, and need to be easily accessible for maintenance and repair.
    I had between 750 and 1000 plants in a 300 square foot greenhouse. It contained a fogger on a humidistat, fans that ran 24/7, thermostatically-controlled ventilation, and thermostatically controlled heating. There was an RO system, a 150 gallon storage tank, and pressure pump connected to the fogger, and to irrigation (hand and automated) after an injection pump added fertilizer. Over the years, I was able to "fine tune" my potting/mounting such that I could water everything at once, amd that allowed me to automate that, using remote control or timers to manage an overhead "rain" system. Had I wanted to, I could have left the entire thing on "automatic" for weeks.

    I spent about $4000/year on propane for heat, in southeast Pennsylvania.

    I'd have given my eye teeth for more space, though....
     
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  3. DanielG

    DanielG New Member

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    Thanks for the pointers.
    - time: possibly the best question. Currently I do about daily 30-40 minutes.
    - Environmental controls will be fully automated. I may want to automate watering a bit more. In terraria it is pretty much fully automated as well, using MistKing system. I can leave that unattended for weeks as well. Can you tell a bit more about your "rain" system?
    - Utilities, no worries.
    - Well understood re large = stable, but there is the trade-off with large and empty.
    - Re climate zones, been wrangling with that. Most of my plants are "intermediate temp."; for cool and warm species I have a couple of terraria. Light zones are easy, but temp zones with ample ventilation may be more slight.
    - Equipment. Some can be set-up outside of GH, such as swamp coolers, RO system. Heater can be overhead.

    What sort of plants are you growing? Average size? Mine are about fist/double fist-size on average.
     
  4. Ray

    Ray Orchid Iconoclast Supporting Member

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    The rain system was nothing but a network of 3/4" pvc pipe into which I inserted spray nozzles, and it was turned on or off via a solenoid valve controlled either manually by a remote system I built, using wireless technology akin to garage door openers, or automatically with a lawn irrigation timer if I was going to be away.

    I don't know where you live, but as someone who has been selling RO systems for 20 years, I don't recommend that they be outdoors, as temperature can have a huge impact on their efficiency, not to mention UV degradation.

    I'm not sure what your concern is about "large and empty." The closer you come to a geodesic dome in shape, i.e., a square foundation versus an elongated one, the more energy efficient it will be. Besides, greenhouses, in my experience, don't stay that way!

    I don't know if you can do so, but if you can sink the floor of the GH into the ground, it'll add thermal stability, and energy efficiency. If I could, I'd go 4' deep. I saw one once that was 8' deep, with only the roof being glazed, and it was an awesome environment.

    As to temperature zones in a greenhouse, I think you'd be surprised how effective a few plastic sheets can be at stratifying stuff. Assuming a central aisle, floor-to-ceiling sheets creating a "wall" of about about half- to 2/3 of the total width can create a significant temperature difference between the end with the heater and that without.

    The vast majority of my plants were paphs in 4.5" or 6" pots, but I had stuff in thumb pots, on twigs, etc.
     
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  5. seidenfaden

    seidenfaden Active Member

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    The only drawback I can see is that, depending on where you are situated, it would cost more to heat up your greenhouse.
     
  6. Chuck-NH

    Chuck-NH Well-Known Member

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    Even with the considerations of cost, time, etc., nearly every serious "Greenhouse Orchidist" I've met has said they wish they had built a bigger greenhouse! Empty space as Ray indicated is not an issue for long and we have running jokes in our local society on where we ask publicly "how long did it take to fill your greenhouse"? I am on my third greenhouse. The first two were in that 200 - 300 sq. ft. range and the current and maybe last is 1800 sq. ft. I have a wall in the middle and half is heated for intermediate/cool orchids and the other half (for seasonal crops) is heated to just stay above freezing. And I've started to encroach on the the other side with Orchids that like cold dry winters .

    In my bigger greenhouse...when it was empty, I did have issues with little Pleurothallids so even built a little enclosure with a fogger to give them the humidity they needed. Now with a full greenhouse and improved controls over the years, I can grow and bloom many cool growing minis that require high humidity right in the open. I am thinning out my larger plants to be able to grow more minis. I do find the climate stability of within the larger space is a plus and also finding the unique microclimates to accommodate different types of orchids as well. My biggest concern with my current greenhouse is not whether I can maintain it now, but what about 10 years from now?
     
  7. DanielG

    DanielG New Member

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    Thanks for feedback and info. Location will be Santa Barbara, California, so pretty mild weather. Hardly ever below freezing, usually not above 85, very rarely above 90.
    Interesting point re UV degradation. There should be enough space underneath benches to put RO system and water storage there.
    Started to make some scale drawings of a 22x23' (so ~500 sqft) GH. Does not seem too big, indeed. Chuck: ~1000 sqft for orchids, I think that will be excessive for me. Not sure I could find enough material that interests me. I mainly do malaxids.
    I had been thinking about some sort of walk-in closet with special conditions (hot growing with additional heater, or cool growing with proper AC unit); currently I have a couple of terraria that serve that function. I may keep that in mind as an optional modification later.
    Re sinking in, interesting idea. I am looking at a Florian Geneva, and that has eaves at 7', ridge at 10.5', so have been thinking of 3' knee wall, or alternatively sinking it in by 3'. No idea about permitting conditions, which may well dictate the approach. Have to chat with contractor eventually.
    Alternatively, I may check whether I could get a taller than standard GH with glazing to ground. Not sure about pros and cons of either approach. R value of double pane low E glass is 3.4, while 6" concrete is around 1.6, which makes glazing preferable.