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Pricing Greenhouses

seedjar

Let's positive thinking!
So, I may be in the market for a greenhouse very soon. (Hooray!) But there are so many choices... I'm not sure where to begin looking. I know that I want it to be expandable, because I'll probably get one that's just big enough for my current collection if I get it any time in the near future. (It would be nice to be able to section off part as a hothouse, or add on a smaller unit as a hothouse, as well.) I'd also like to be able to attach it to a shed or outbuilding, so that I can have some built-in storage without using up space where plants could be growing. I probably won't need to worry about a heater until next year, as I doubt I'll have the foundation ready and frame up before it starts warming up for Spring, but I was thinking it would be nice to have a wood or pellet stove in the shed part and use some sort of heat exchanger to warm the greenhouse area. A thermostat-controlled propane heater would probably serve as the normal heat source, with the stove for back-up. But vents, humidifiers and maybe an A/C will definitely need to be in by May/June.
Here's a little list of the things I'd like to include (mostly inspired by the greenhouses I've seen here on TF) -
- 12 x 8 feet or so
- Sunken foundation
- Wiring for lights/greenhouse appliances
- Shelving (freestanding or built-in? I'm torn.)
- Vents/fans with automatic and manual controls (since the thermostat comes later)
- Heat/air conditioning with the same
- Backup generator (this would be out in the boonies, so needs to be able to weather a power outage)
- Outside composter with a heat exchanger (did you know a healthy compost pile can get up to 170F at its core?)
Did I miss anything? Just trying to sketch out some dollar figures here. This will be an ongoing project, so like I was saying, not everything needs to happen at once. I'm just trying to get a sense of the various costs and what brands are the best (in terms of durability, light availability, and affordability.) Any ideas/help/links would be excellent.
Thanks,
~Joe
 
Well you got your work cut out for you!

First if you have the room, make it bigger than you think you need.. alot bigger! It is easier to setup bigger than it is to go back and expand. The majority of the cost isn't in the greenhouse structure but in all the equipment to make it run. It won't add a whole lot more cost to get equipment designed for a larger greenhouse so go direct for the larger structure now! hehe

This is a good place to start http://www.igcusa.com/ They have a seperate division for supplies http://www.greenhousemegastore.com/

First thing you need to figure out is what temperature range will you be running or multiple ranges if you split up the inside. Then you need to compare with your outside temperatures during the hottest time and coldest time of the year and decide if it's feasible to replicate the temperatures inside that you want to achieve. Generally speaking it is easier to raise the inside temperature above ambient than it is to lower it below ambient. Alot will also depend on how much you are willing to spend on utility costs to maintain said temperature zones! There are various methods to raise and lower temperatures. Their effectiveness and utility costs vary depending on just how much cooling or heating you need.
 
That's kind of what I thought, re: going for more space than I need. But, I could get a small used greenhouse for super cheap from craigslist, which is tempting. Perhaps once I grow out of it, I can get a second, larger one, put them back-to-back, and use the smaller one for a hothouse. My N. bicalcurata should be sprawling out by then. Fortunately, I already have a decent indoor setup for my tropicals, so this can be an incremental project. Right now I'd just like to have the greenhouse to overwinter my temperate plants and get them started early. As I have time to improve it, I'll add fans, a swamp cooler, a heater, etc. But yes, from what I gather so far, the overall price can get pretty steep. What size would you recommend for someone with about 180 species, with about a dozen ten-gallon pots of Sarrs and 20 large Neps in 10" square pots? My outdoor collection presently takes up at least 40 square feet, maybe a little less if I could find a tray big enough to pack them all in next to one another.
~Joe
 
You can always add to an existing greenhouse by extending it or adding a whole new structure to one end.

I guess the first question.. if you are planning to overwinter your current outdoor collection in an unheated coldframe this Winter, and then you make it a tropical house next Summer, what are you planning to do with your outdoor collection the following Winter?

As for size.. hmm I dunno. Depends how you answer my first question and not sure how much space you have to build on, what your budget looks like, what you will end up paying for utility costs to run the final setup. These would be in my opinion the main factors. It is not really all that bad to put up a pretty good size structure and then get it running. The main concern at that point is heat/cooling costs for operation.. Of the two, heating can get very expensive very fast if you need alot of it for prolonged periods.

There are calculators to help figure out how much heating you will need to reach certain temperatures and estimate ahead of time what your heating bills might look like. The variable include surface area of the greenhouse, glazing (material) of the greenhouse roof and walls, temperature differential between inside and outside.
http://www.igcusa.com/greenhouse-btu-calculator.html


This is another good sight to shop and compare prices on everything from structures to equipment
http://www.growerssupply.com/farm/supplies/home


Just a side note. I am glad to see you considering a back up generator. That is a good first step to preventing disasters. I would also encourage you to do the following when designing your heating and cooling systems. A generator is good for when the power is out but it will not help if a motor burns out or a breaker pops.


1. Oversize your heating and cooling a little.

2. Make them essentially two systems for each, independent from each other. So for example exhaust fans and heaters use two of each, seperately wired. Combined they can satisfy your criteria in #1 but that way if a motor goes out or a breaker pops your greenhouse isn't dead in the water with no heating or cooling. Will cost more in the short run to buy two smaller units of each rather than one bigger sized unit and extra thermostats, breakers, wiring etc. But worth it in the long run.

3. Phone alarm system. They have nifty little systems that monitor the temperatures and if they get too hot or cold will call a preset number and let you know something isn't right. Particularly handy if you don't go with the plan in #2 or your greenhouse is somewhat remote and your backup generator is not automatic.

Contrary to popular belief. The greatest danger is not a heater breaking in Winter.. but it is a vent system breaking in Summer. Greenhouses in full sun can cook and fry your plants in the span of 10 minutes if the exhaust system fails. Freezing in the Winter from a failed heater takes a whole lot longer.. as the greenhouse cools down the rate it cools slows the closer it gets to freezing.
 
that would be pretty much why i havent built one......i can buy a greenhouse for what i have spent on a couple rifles, the support equipment and the cost to run it is what has stopped me......basically my plan is to build a sun room off the back of the house in the future hooked in to our central air, with large windows that i can grow the hardier species in......figure the touchy stuff will never leave my basement.....i only have decent weather for running a green house 4 months out of the year, the rest ill either be heating it or cooling it.....would cost me a fortune to maintain the perfect temps for either the true highlanders or the true lowlanders
 
As for alarms, I'm familiar with call systems (for things other than thermostats) and was thinking about putting one together. I actually have a couple of old junker computers and would like to use that as a programmable control unit.
I'm in zone 8a/b so all of my temperate plants live outside year-round already. I have a few Sarracenia that would enjoy milder winters and higher highs in the summer (S. minor "Okee" comes to mind.) I have indoor space for Neps, with good temperatures and ample light, so my motivation to move them to the greenhouse is merely so I can let them sprawl. I'm not entirely sure how much space I'll have to work with - I'll be taking measurements this weekend - but large vegetable beds are going in now so I believe I'll be able to snag a plot for a bog. I also talked about installing a water feature and the owners sounded pretty excited about that. My tentative plan is to overwinter all of my outdoor plants in a basic coldframe setup to protect them from animals and any unexpected weather. Depending on the order in which things get done, I'll gradually move plants that would prefer outdoor weather to the bog or benches (with ample poultry wire to keep out curious chickens and terriers.)
Once the greenhouse is no longer home base, I would like to install a couple minibog-type setups in whiskey barrels or the like inside to house my warm-loving Sarrs, and the remaining space would be used for highland Neps and experimenting with other tropical/subtropical plants - last year I had a lot of success with my sundews outdoors, so they're definitely on the agenda, and depending on how my Ceph and Heli come through the Winter I might consider them, too.
Fans, vent controllers and swamp coolers seem to be the cheapest elements to buy, so I'll focus on that stuff first, along with some sort of autonomous control setup. For heat, I was thinking I would get an electric, preferably one with an independent fan control, and later on a gas backup (hopefully with some sort of automatic controls... they make those, right?) The power will depend on the size of the greenhouse, of course. I definitely hear you on the back-up systems, but I'll probably have to buy them one at a time. If I end up going with this smaller used setup, I'll have some spare cash to start things right, but otherwise it's going to be a work-in-progress for a while.
Here's the average temperatures in the area:
lha23309.png

Humidity averages high - 90% mornings with 65-80% afternoons. The land is built on a hillside with southern exposure and little natural shade; one of my first projects will be to plant a few fast-growing trees and hedges as windbreaks at the edges of the property. Which is not to say that I'm worries about wind - I understand that it's breezy in the area but not prone to big windstorms. The local almanac says that they get yearly winds up to 60 mph and 80 mph every ten.
I'll look over the numbers and try that calculator you linked. I like the idea of having a hothouse inside the greenhouse to make heat control simpler, which will skew the numbers a little, so I guess I'll just round up.
Thanks again,
~Joe

PS - For a 12'x8'x6' glass enclosure, going from 30F to 80F would take 22337 BTUs. I definitely don't need this much heat any time soon. To 65F is 15636. 10'x6'x6' works out to 15455/10818, respectively. But 30F is a rare occurance in the area, so it should normally be much less. 12'x8'x6' from 45F to 80F is 15636, and 8936 for 45F to 65F. 10'x6'x6' is 11486/6563, in this case. Does this seem feasible? How can I estimate the insulating effect and its consequences on the cooling costs in the summer? With average highs in the 70s I'm not anticipating ever going too widely outside of acceptable high temperatures inside - I'll aim to be equipped for such but plan not to use it often regarding my utility expenses.
 
OK, rereading your post I understand more what you're saying about buying two smaller units each. But if I'm acquiring the expensive parts like heaters before I really need them, would it be better to get two redundant units of the same size? I imagine that a larger heater runs more efficiently than two smaller units that add up to the same output, and the way things are usually priced it would probably be cheaper altogether to get two heaters that can each do adequate heating on their own. I guess my approach will ultimately depend on how soon I'm able to get the money together.
~Joe

PS - Ack, even more questions. Can the heaters be too large? If I have too much heating capacity and I only want to increase the temperatures a little, such as keeping it warm enough for highland Neps, will the change in temperature be sudden enough to upset my plants?
 
depends on how they run......for example, my parents have a furnace about 30% to large for their house and its constantly burning through parts......why? cause that style of furnace is meant to run for longer periods of time......as is it kicks on....blows air for a short while(few minutes) than kicks off.....ideally it should kick on, run for 15 minutes or longer than kick off but since it pushes so much air in such a small house its constantly kicking on and off which burns out certain parts of the furnace......so they are constantly fixing it......

so basically the answer is ask the manufacturer how it tolerates kicking off and on more often if your using one bigger than you need.....some can prolly handle it fine, some maybe not so much......
 
At least your temperatures are pretty moderate ;> That helps!

Yes it is possible to have heating and venting that is too excessive. The plants don't really like to have rapid changes in temperature.. or be blasted by alot of direct heat or cold. Gas heaters also have to get to operating temperature first so if it it way oversized it will have more waste in preheating the heater then shutting down quickly afterwards.

There are various ways of doing it and lots of decisions based on how far away the structure is, how good your alarm system is, or your ability to get there whenever there is a problem, or budget etc etc etc...

IGC has a great Faq area where you can find lots of other calculators and advice on various greenhouse systems http://www.igcusa.com/faq.html

so, lets start with your venting/cooling. Your local humidity is fairly high already so swampcoolers will be only marginally effective and with air temperatures not too bad you are probably better off just going with simple exhaust fans with a fogging system for humidity control. To calculate how much air you need to move you need to calculate the volume inside the greenhouse in cubic feet. You then need to size your exhaust fan to remove that volume every few minutes. I use two exhaust fans of the same size and set one to come on about 5degrees sooner than the other. My fans are sized so that only one usually runs except on the hottest days. So one fan can totally exchange the air every few minutes while both combined will do it twice as fast. Too fast though and you get yourself a nice windtunnel that will suck your plants dry in no time!

So during the Summer here as the greenhouse warms up. (note that my underbench fogging is set for temperature control not humidity)
intake vents open
Fogging goes on
first exhaust fan goes on
second exhaust fan goes on

Heating is pretty straight forward. You could go with two smaller units that will basically run in conjunction or you could go with one main heater and a smaller one for backup emergency. I don't think I would go with two full sized.. heaters can get pricey and they take up alot of space too.

If you size your heaters so that you can reach your desired high temperature on the coldest night that you might ever reach then you have built into your system plenty of extra margin and for most nights there will be more than enough reserve heating capacity. The heaters will also not run for excessively long periods or be so oversized as to waste alot of fuel as mentioned above. With a smaller structure I would me more inclined to go with a larger main unit and a small backup vs two that will run in conjunction to give you the capacity you need.

Some other thoughts that kinda go along with heating systems, and greenhouses in general..
Greenhouse air circulation to help distribute/mix greenhouse air so you don't have all the hot air sitting at one end.
You may want seperate day and night temperature settings for your heating/cooling systems. Particularly if you plan to have more than one temperature zone.
Use equipment designed for greenhouses. Items from the hardware store for household use won't last.
Wet greenhouses and electrical equipment = potentially dangerous, make sure everything is ground faulted! I use all ground fault breakers. Simply grounded isn't enough.

Hopefully I haven't scared you too horribly. It really isn't that bad if you plan it all out. But you can see how much planning it can take to put together a properly balanced greenhouse so that changing the size later can drastically alter your growing conditions/equipment needs.

Final thoughts. Inflated poly (greenhouse grade) is cheapest but the insulation is not as good. Rigid double or triple wall Polycarbonate looks great has better insulation but is noticeably more expensive. Forget glass. You would need a solid concrete foundation to support the weight, and the insulation factor is worse than the inflated poly.

Final final thoughts. Once it's up and running it will take some time to figure out what will grow best and where inside the greenhouse. Placement of heater, vents, air circulation fans etc will all affect various areas of the greenhouse. You will find some areas are naturally warmer and others cool, or some have brighter light than others and so on.

Any questions just holler!
 
  • #10
Not scared at all. This is all great information; thanks! How often does rigid polycarb need to be replaced? I was very disappointed with the durability of the flexible stuff. I was thinking glass would be nice because it lasts - heat loss was a concern, though. I'll definitely keep that and the weight in mind. This weekend I'll have a better idea of what I might be working with - I'm sure I'll have more questions by then.
~Joe

PS - I saw a greenhouse heater that could run at different wattages with different resulting BTU outputs. I assume that at lower wattages, it would heat more slowly and to a lower operating temperature. Do you think that would be a decent control for temperature concerns? It also had a separate fan control, built-in thermostat and three-way switch (off, on, thermostat.) Seemed like a good deal for my purposes, and I haven't found many electrics yet that compared in terms of $s/BTU.
 
  • #11
The rigid polycarbonate about 15 years, the 4year greenhouse poly you can stretch to 5 or 6 without problem usually. Amount of shade cloth and how many months out of the year will affect the durability of the plastic. The more full sun directly on the greenhouse covering the shorter the lifespan. The times I listed though are with full sun all day every day. They are quite durable to the UV.

Inflated poly also has it's own set of challenges though with keeping it inflated hehe
 
  • #12
I see... that's much better than I thought. What about your own setup? Did you buy a greenhouse kit or construct your own? I've seen a lot of people say it's much cheaper to build one from scratch, but I'm kind of thinking that a steel frame would be better than wood, and I'm no metalworker.
~Joe
 
  • #13
My first greenhouse is just one of those cheap steel hoop houses with the inflated 2 layer poly covering. I bought that one from a friend many years ago. The new greenhouses are steel gutter connected type. Much bigger with alot more headroom and tall straight sides.

I have seen some very nice homemade structures so if you are handy with carpentry you could probably put something together. They are not too complicated. Anchoring and structural support against the wind would be your main concern based on your weather. That and support for any hanging equipment. Pressure treated lumber will certainly last plenty long. I have seen some kits and setups made out of pvc pipe... Not a good material in my opinion.
 
  • #14
Oh and no I have not built my greenhouses totally.. they are kits. Like a giant erector set! But I have put together plenty of benches and endwalls and such from lumber
 
  • #15
How do you think one of those steel kits would stand up to the wind I described? This property is up on a hill so I'm a tiny bit concerned. There is an old 1890's-era garage that's still standing on the same area, though, so it seems manageable.
I am good with carpentry, but I've never done framing before - just building furniture. Depending on what kind of help from friends I'm able to get, building my own may be an option, but there are only so many favors I can call in so I've got my eye on kits for now.
~Joe
 
  • #16
I don't think it would be a problem as long as the structure is properly anchored.
 
  • #17
Great! Thanks again for your help. I'm excited about checking things out tomorrow in-person. The pictures I've seen don't really show plot at all, so I've just been going by a vague description. I'll follow up with some details later this weekend.
~Joe

PS - I'm surprised there aren't more people chiming in on this thread. I remember when we had quite a few regular posters with very nice greenhouses.
 
  • #18
Joe, I too have actually been looking into designing and building a greenhouse for my neps! From the very little research I have done, the rigid poly-carb seems to be the best bet for our area. You are right about how our typical lows are around 35 degrees throughout the winter, but don't forget the cold snaps we get here and there that are in the teens or lower. For my set-up, I was thinking I would go with a main heating unit and a small back-up. Since location is a factor at my place, I am building a unit that will face the south-southwest. I am looking at a 10 x 15 greenhouse, but the actual part not under my deck is closer to 10 x 6. If you could build it against another structure, especially the house, you are looking at saving some $$ in heating with the insulation of building next to another structure. Also, electircal and maybe water would be closer. I don't know if this is an option at your place. Lastly, have you looked into materials from Charlies Greenhouses? You can buy the poly-carb from them in Mt. Vernon if you have the ability to truck it down to Oly yourself. Good luck on your project. I don't think mine will be in for another year or so. (I am on the slow boat schedule with too many other house projects to do right now).
 
  • #19
Tony..... would u say that using this: a 6' x 4' greenhouse INDOORS (http://www.greenhousemegastore.com/prodinfo.asp?number=HG-ES) is a good choice than me trying to go for a terrarium style with a 4' x 2' tank? The tank is very expensive. I like this greenhouse...but my concern is...if I use it....what kind of lighting do I need? Will a 2 x 4' 2 lamp T8 suffice if I cover every panel with mylar?

Also...the issue is.... is this greenhouse disassemblable and reassemble easily?? I will be moving in a yr so I don't want to invest in something which is a one time assembly.

thanks,

V
 
  • #20
Hey everyone, i might be a little late into the conversation, but me and my parents just built a greenhosue this summer, heres some details

it is a 12x10xnot sure on height like 9-10;ft greenhouse, its constructed of wood, and there are some shelving units enough to fit a plant on all the way down the 2 12ft sides, i forget what kind of fencing we used but its, heavy maybe cattle fencing? which made the dome for the top of the greenhouse, and it is covered with a 4-6mm plastic, i can get pics.

for this it costed about $400-500 to start it from scratch, we even cleared trees and weeds to build it, which i will be planting more trees... it has a gravel floor which was free, or if you want to say for the cost of gas, got if from the dump. it is built into the ground so it will not be moving, its at least 4ft into the ground, and the other thing about this greenhouse is for next year, i plan to expand it, i can't expand the width but i can go back about 12-24ft back, with some manual work to clear the area, this would be an estimate of $100 or cheaper to build back in about 5ft sections. it is a tough looking greenhouse and we will probably replace the plastic next year, as right now you could put the saying "duck tape fixes everything" to what the greenhouse looks like, its mainly the doors because they are just plastic and the wind caught them

next year i will be trying to put in some solid doors, which we were thinking, old shower doors? has anyone else used or thought about this before? this isn't a high tech greenhouse but its a nice large hobby greenhouse.

It housed all the plants i have, this comming seed starting period i plan to start tons of vegatables and possibly some flowers, and of course when temps get high enough my neps and tropical plants enjoy there own area of the greenhouse. flowers are the if'y, i would like to start keeping bees and would think they would greatly benefit from having more sources of pollen rather than just the veg.
 
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