Greenhouse lighting

whispersiren · Jul 18, 2004

Hi,
I've been contemplating building a greenhouse primarily to hold my Nepenthes collection, which is outgrowing its terrariums faster than expected...

I really have no clue as to whether my concerns about this project are crazy, paranoid or moranic, so any advice specifically with regards to neps and greenhouses would be appreciated.

I suppose, my first concern is with the sun overheating it during the day or burning the leaves... and so was thinking about placing it in the shade and adding artificial light to suppliment the light... (is that overkill?) I was also thinking that a small solar panel would be the ultimate way to charge the battery (and humidifier? and fan?) for the lights and am wondering if anyone knows where to find something like that? or another option would be to place it in the sun and use frosted glass for the ceiling to make the sun less harsh and burning?

Because humidity and cool night temps are an issue with neps I was wondering how quickly a 10'x12' glass enclosure would cool at night on its own without opening it up? It's usually in the 50's here at night. Or if I did open it up, could I build smaller clear plastic sheeting "walls" inside to trap humidity?

Shucks (scratch head, rub chin) any websites or books on the subject or pics of your setups would be much appreciated! (grin)

Thanks so much (in advance) for helping!

Lia

Sarracenia0 · Jul 18, 2004

I would not put it in the shade. My greenhouse is in mostly shade (I only get like 1-2 hours of sun in the summer; none in the winter), and I have problems in the winter with lighting. I had to spend a lot of cash to get a HID light which lowers the humidity and heats up to gh (which doesn't help because here in the Georgia summer as it gets up into the high 90's to 100's) then had to buy a humidifier. So........ I suggest you put it in the sun and put a shade cloth over it if it gets too much sun. But you do need to get a gh that has some vents; neps enjoy air circulation, a fan would be of help also.
It would cost too much to supply sufficient light to a whole gh.

As for night temps it should cool down fine, if you open up some vents. It shouldn't lower the humidity too much.(Unless you live in the desert) If it does drop too much you can buy a small humidifier.

As for websites here is one of the best I think.
http://www.cpjungle.com/nepenthesuniversity.htm
down at the bottom there is some greenhouse info.

Mike

P.S.
Are you thinking of buying a gh or building one? If you need any help picking one out let me know.

Tony Paroubek · Jul 18, 2004

Better off putting it in the sun and using shade cloth to cut the light to the level you want. To combat the loss of humidity when the vents are open and the exhaust fans running.. put in a misting/fogger system. You can also pull incoming air through evaporative pads to increase humidity and cool the air as it enters the greenhouse.

whispersiren · Jul 19, 2004

Hmmm I suppose the bottom line is to create a set up that has the most versatility: locating it in the shade would be limiting... as would fixed frosted glass as opposed to shade cloths. cool. (grin)

How are most smaller greenhouses rigged for electricity?? I will undoubtedly need some motorized equipment like an exhaust fan, humidifier, mister timer...

I'm still in the "research stage" building vs. buying. I am set on the size being somewhere in the 10x12 or 10x16 would be ideal, but 8x12 or 16 would be ok if i found a reasonable kit. I like polycarbonate as opposed to glass, though may resort to building the frame and using double ply film until I can afford the polycarbonate.

The real question is whether building it myself would save much money in the long run. I'd rather spend more to get exactly what i want as opposed to spending more over time continuously upgrading & expanding & enlarging. I think the plants too might prefer not being moved around too much.

Mike- if you'd like to pass on any gh designs or brands that you particularly like or recommend. i would certainly appreciate the help (big grin).

groovy,
Lia

Tony Paroubek · Jul 19, 2004

Not exactly sure where your located so your setup needs will vary based on your local climate and the climate your trying to create within your greenhouse.

Nice to have it in a sunny spot as you can then shade different portions with different amounts of shade cloth. Putting it in a shady spot to keep it cooler will cost more to run lighting than it will to run exhaust/misting (probably)
You might save a few bucks building the frame yourself but generally speaking the frame is not the expensive part if you buy one. Polycarbonate is great but expensive. Double layer inflated poly is not very pretty but works well and is much less expensive.

Planning is deffinately the key to avoiding changes later.
Some things to think about...
What temperature day/night are you shooting for? Will it change between Winter and Summer. Once you have a range to shoot for..Then how are going to achieve it? ie cooling in the Summer? Heating in the Winter?
What kind of cooling or combination of cooling methods?
What kind of heating system?

How to supply electric and water. Probably can call an electrician and a plumber in your area to get some ideas and estimates.

And finally.. what to do in a poweroutage if it happens during the Summer or Winter.
Tony

whispersiren · Jul 21, 2004

There's a lot to think about...

I live in the "mountains" near Los Gatos/San Jose, CA at about 1500 ft. To the best of my knowledge: the winter day temps. are in the 40-70s F with dips into the 20-30s F on an occasion. During the summer day temps are between 70-85 F with an occasional jump up into the 100s. Night temps are 30-55 F in winter 50-65 F in summer.
Ideal temperature range for greenhouse: 60-80 (day), 45-55 (night). As for humidy... I'd say about 40% maybe (?)... we have early morning fog about half the year that burns off in the afternoon. A humidfer/mister/fogger system could be used to help with that.

As for heating: a space heater could be utilized on nippy nights/cold days.

Cooling is the tricky part. Exhaust fans would certainly work at night to help cool, but would only circulate the gh air, on ultrahot days. Air conditioners are a big NO. Any ideas?

As for electricity: I would like to go solar (it is sunny california - grin), if possible, which would work even during power outages... but may be out of my initial reach expense-wise.

Recommend any books, websites or catalogs for equipment pricing or gh designs?

Tony-prior to your "commercial days" did you have a gh? Where did you gain most of your knowledge before you started your business?

Lia

Tony Paroubek · Jul 21, 2004

O gosh.. I had a greenhouse as a teenager growing up at my parents place and have lots of hands on experience with several different types of greenhouses and setups over the years. I also have had some schooling in agriculture as well as a number of friends, hobbyists and other commercial growers with greenhouses. With all the different types of greenhouses and materials used to construct them, there are many many ways to control the environment. The key is knowing what type of environment your trying to replicate and the change from the outside environment. I think your well on your way to putting together a system that will perform and give you the parameters your looking for.

One thing I forgot to ask is what kind of plants are you growing? If it is mostly Sarracenia, Drosera, VFT etc that don't require high humidity, then things will be easier. But if your growing lots of heliamphora, Nepenthes and other high humidity plants then things need to be a bit different.

Sounds like the space heater for Winter would do fine. Cooling at night is not an issue unless your purposely trying to reach 45-55. As during the Summer you just set the heater down low so the greenhouse just runs at whatever the night temperature hits and during the Winter you set it at whatever level you want.

As far as exhaust fans.. they would not be running at night. They would run primarily during the day to force hot air out one end of the greenhouse while cooler outside air came in the other end. You also should have circulation fans in the greenhouse to just keep a gentle breeze going in there 24hrs a day. This will reduce pathogen problems as well as help equalize temperature in various parts of the greenhouse.

Unfortunately I don't have any experience with solar so can't help you there.. but if you can find a way to help on the electric with running various fans and pumps then great!

IGC - International Greenhouse Company has a very nice website for greenhouses and supplies but they also have some decent information on greenhouse function and various ways of controlling the environment. I agree cooling and humidity are going to be your biggest issues (moreso on the humidity if you want to grow the tropical type plants .. Nep. etc) Check out their FAQ area. They have a section specifically for cooling which highlights a number of the more typical ways to cool a greenhouse and how each functions. As well as the equipment to make it work and a rough idea on how much cooling you can expect over the outdoor temperature. (Note that in all cases for greenhouse venting the temperature inside the greenhouse will be warmer than outside UNLESS you install evaporative cooling of some sort. Which is why I recommend this type of cooling because while it also works well to cool the greenhouse it increases the humidity in the same process)IGC FAQ

Tony

The Griffin · Jul 22, 2004

If you are growing highland plants, your natural temps do not seem too far off to begin with. We had a 107 heat index the last couple of days in NE, lol.

Joe

whispersiren · Jul 26, 2004

Tony- IGC, exactly what I was looking for - thanks a mill! (grin)

Joe- The Northern California coast is ideal for highland plants (as you can see from Caplock's incredible nepenthes!): fog, cool temps etc. My house is a little inland (not quite as ideal) and so gets an occasional killer spell in the 90+ range with the night temps staying around 65+ (for 1-2 weeks)... during that time (if it's in the triples digits in southern california especially) we still have the excitment of "rolling blackouts." woo!