Grow room vs Greenhouse?

[samuelforest]

I just wanted to have your opinions on what you found the best to grow tropical plants in cold climates. Maybye jay could help me on this and others. What are the qualities of a grow room and a greenhouse?

[CoPlantNut]

If cost isn't a consideration, a greenhouse is the way to go...  You may have to supplement the light in the winter if you're far from the equator, but you can make use of all the free sunlight you can get.  Artificial lights do work for growing plants, and they even work well for growing short plants (about 5 feet tall or less) but they aren't as good as the sun.

I say this as someone who has a rather extensive grow room; if I had the land to put a greenhouse on, I would have a greenhouse instead.  It would cost more, there are more potential issues with heating system failures, and it is more work to maintain...  But being able to grow taller plants and plant things in the ground would make it worthwhile.

   Kevin

[nullzero]

I would think it would come down to energy costs. If the costs are cheap then the grow room would be the way to go. However if the energy costs are high, a green house would be optimal. Also min. winter temps would be a big factor, a grow room would be easier to keep warm.

[CoPlantNut]

I would think it would come down to energy costs. If the costs are cheap then the grow room would be the way to go. However if the energy costs are high, a green house would be optimal. Also min. winter temps would be a big factor, a grow room would be easier to keep warm.

A grow room is certainly easier to keep warm; in fact the issue you run into as you start making larger grow-room setups is keeping it cool enough- those lights put off heat!  Even the LED fixtures I've seen advertised as "heatless" put out a fair amount of heat.   

   Kevin

[Invar69]

I have a group of mango trees growing in a sunlit room (my office) and a couple in my friend's greenhouse. Both do well but the plants in the greenhouse grow a lot faster. I get a growth flush, on average, once every five months (for the room mangoes) and 6 weeks for the greenhouse. The temperature of my room is a pretty constant 65°F night/75°F Day. The greenhouse gets very hot (95°F day - although, I think that's too hot) but the mangoes seem to like it.

[TropicalFruitHunters]

Humidity and size I believe would be other key factors.  You can't start pumping humidity into your home required for tropical plants.  Size will get you sooner in a grow room than a greenhouse.  It's all in what you want to do.

[samuelforest]

I would think it would come down to energy costs. If the costs are cheap then the grow room would be the way to go. However if the energy costs are high, a green house would be optimal. Also min. winter temps would be a big factor, a grow room would be easier to keep warm.

Null, the energy in Quebec really cheap about 7cents per kilowatt. It the cheapest in all Canada.

I have a group of mango trees growing in a sunlit room (my office) and a couple in my friend's greenhouse. Both do well but the plants in the greenhouse grow a lot faster. I get a growth flush, on average, once every five months (for the room mangoes) and 6 weeks for the greenhouse. The temperature of my room is a pretty constant 65°F night/75°F Day. The greenhouse gets very hot (95°F day - although, I think that's too hot) but the mangoes seem to like it.

I saw your mangoes on your blog I think. You have a great collection, but I wonder why they don't go outside?

Jay, is it expensive to heat a greenhouse and do you use artificial lghts? My garage is 12feet high, so I can push a little bit and I won't let my trees get to that size hopefully.

[samuelforest]

Kevin, why artificial light can only support the growing of a 5 feet tall plant?

[KarenRei]

I've done both grow rooms and greenhouses, and I strongly recommend grow rooms.

 * Your central heating can almost certainly heat it cheaper, probably a *lot* cheaper, than whatever system you put in your greenhouse.
 * Temperature management in outdoor greenhouses is a real pain, both cooling in summer, heating in winter, and day/night temperature balancing.
 * No worries about carbon monoxide or - worse for plants in a greenhouse - ethylene.
 * The air exchange with your house also *dramatically* helps with humidity control.
 * You can either build your greenhouse on the cheap, with plastic film, etc - wherein you'll find it to be a big maintenance and leak pain - or you can build it on the expensive, wherein, why not just attach it to your house?
 * It may not sound like fun walking out to your greenhouse in the middle of winter when it's cold and snowy out, but just wait until you see how not fun it is when you have to keep doing it over and over!

If you have any hope of doing a grow room, I strongly advise that you do it.

Now, if you're using an existing room of an existing house, some cautions:

 * The big one: Keep that water off the floor!  Your initial thoughts on how to do this are probably wrong.  For example, thinking of just putting down a tarp?  I guarantee you that at least some point water will get under your tarp, and now your tarp has gone from rot protector to rot *promoter*.  Had to refinish my wood floor because of that.  No, the key is air space.  You want as minimal contact with the ground as possible, no more than poles/wheels from shelves or wires from racks, so that air can circulate under everything.  Then, you want all pots to have saucers or trays, which are themselves over the ground.  That way you minimize what water makes it to the ground, and when water invariably does make it to the ground, it can still dry.
 * Indoors or outdoors, spider mites are going to be a pain.  Fact of life, sorry    Get your spider mite plan in place and check your leaves every week for webbing and "speckling", and when it comes, start isolating and treating.  Note, "when" it coes, not "if".  Aphids are not a guarantee but are likely at some point or another.  You may also get fungus gnats, but they're a sign of overwatering overly-organic soil and can be prevented with proper soil management.
 * Be ready for a big power bill unless you make good use windows (which I strongly recommend!).  Always favor capital costs over operating costs - that is, spend money to get more efficient fixtures rather than using whatever cheap stuff you have, get as big of windows in the room as you can get to capture more free light, etc.
 * Leave the door open!  You want air to circulate.  Leave the air trapped and you'll probably cause mildew problems (as well as losing some of the benefits of having a grow room exchange air with the rest of your house - cleaner air for you, more CO2 and less ethylene for the plants).
 * What sort of hardware you need in your room varies depending on your particular implementation details.  For example, if it's a small room, isolated by a doorway, packed full of plants and light, thermal and humidity control will be paramount.  On the other hand, an open floor plan with a lesser scale of growth and you don't even really need a fan.
 * Have the switches to your lights as close to where you enter the room as possible and keep all electronics (excepting cords, which aren't a big deal) away from water-splash zones.

[CoPlantNut]

Kevin, why artificial light can only support the growing of a 5 feet tall plant?

Samuel,

Artificial lights just aren't as strong as the sun.  Light decreases in intensity as the square of the distance you get away from the light source, so if you have the perfect amount of light 1 foot away from your light bulb, 2 feet away you'll have 1/4 as much light, and 3 feet away you'll have 1/9 as much light.  You can add more lights, but then the tops of the plants get baked with too much light and the bottom leaves still don't get enough. 

The sun is very, very bright, and a convenient 93 million miles away; the leaves at the top of a tree in sunlight get just about as much light as the leaves at the bottom of the tree because the extra 30 or 50 feet further from the sun makes little difference compared to the 490 billion feet from the top of the tree to the sun.  That just isn't possible with artificial light.  You can add lights pointing in from the sides, but that starts creating other problems as well; eventually each tree will need its own light-surrounded grow room.

If you're only trying to grow a few small plants, a grow room is probably the most economical and almost certainly the easiest way to go.  As your collection grows in number and size, a greenhouse will become the more attractive option.  As you scale up a grow room it starts to encounter many of the same issues a greenhouse does with the need for ventilation, waterproofing, humidity control, cooling needs (versus heating for a greenhouse)...

As Karen said, spider mites will be a problem.  High humidity suppresses spider mites.  But you can't raise the humidity in your house without growing mold.  If you start growing a lot of plants, they will start raising the humidity on their own as well...  My last temporary grow room was 12 feet by 8 feet and only had a couple hundred plants (mostly small) but raised the humidity of my entire basement enough to start causing problems.  So I went with a "virtual greenhouse" approach of building an air-tight plastic lined room so I could keep the humidity high without growing mold in my house.  But a sealed grow room will quickly overheat, and isn't good for the plants anyhow, so I needed to ventilate it outside.  Now I need a controller just like a greenhouse to control the ventilation.

[CoPlantNut]

-- I should point out that artificial lights don't limit the plant size to only 5 feet tall; it is just that only the top 5 feet of the tree will be getting enough light for leaves to live.

   Kevin

[samuelforest]

Thanks karen I do not worry a lot about mold since my grow room is on concrete. It is basically my garage. Do you have tips to raise the humidity? When I bring the plants in should I wash them before with a plant soap? I will wire my 1000w mh on 240v which takes about 5amps. I calculated and that makes it 15$ or so a month runned 12/24.

Kevin, have you had good sucess with grow lights with big plants?

[amaqeq]

samuelforest
to raise or control the humidity in small place like a garage you can connect humidity controller to regular humidifier (the one that is used sometime in children rooms)
if not mistaken an 40$ worth digital humidity controller has high and low options.
simplest way is to position open containers filed with water near the heat source
and to increase humidity even more, those containers can be accompanied with aquarium heating element so that more water will evaporate

if you want specific temperature without central heating or cooling system digital thermostat is even cheaper 20$ it can control high and low most thermostats has also
hysteresis control possibilities

since you made up your mind to go with grow room it is fine
however if you have place in your backyard Polytunnel is very affordable, and if you only use part of it you can hang sheet of the same cover material inside as a curtain and heat only portion of it

in many places who sell the cover you can ask for specific thickness and size
they mostly calculate the price per weight
the metal frame can be ordered also, just simple galvanized metal pipe
metal craftsman may often have an machine to flex the pipe in any reasonable arch measurement, regular pipes are normally 6 meters in length
the arches are  anchored to concrete poured to hole in the ground, same as fence poles are
the concrete may hold a bigger pipe at ground level height as a connection to the
frame arch so that the later can be easily disassembled
simplest way is to throw the cover over the frame and hold it in place with sand stapled
over the margins, than one end you can close like a sausage and at the entrance you can improvise an wooden frame to act as a Door

[samuelforest]

I'll look for humidifer or just try the to put water near the heat source. I already have a digital thermostat. If I build a will I be able to raise enough the tempearture to put my plants out in April and October? Usually we get highs 10-15 celsius and lows of 3-5 celsius and sometime,but rarely we could get a frost.

since you made up your mind to go with grow room it is fine
however if you have place in your backyard Polytunnel is very affordable, and if you only use part of it you can hang sheet of the same cover material inside as a curtain and heat only portion of it

I did not made my mind yet, but I have already built a grow room since it is cheaper than a greenhouse. I just wanted to know if there's a big diffrence between a grow room and a greenhouse.

[KarenRei]

I'll look for humidifer or just try the to put water near the heat source. I already have a digital thermostat. If I build a will I be able to raise enough the tempearture to put my plants out in April and October? Usually we get highs 10-15 celsius and lows of 3-5 celsius and sometime,but rarely we could get a frost.

since you made up your mind to go with grow room it is fine
however if you have place in your backyard Polytunnel is very affordable, and if you only use part of it you can hang sheet of the same cover material inside as a curtain and heat only portion of it

I did not made my mind yet, but I have already built a grow room since it is cheaper than a greenhouse. I just wanted to know if there's a big diffrence between a grow room and a greenhouse.

As a side note, if you grow enough plants, they'll be their own humidifier, to the point that they can mildew up drywall (not an issue in your case) without help. 

I briefly mentioned the maintenance issues of plastic-film outdoor greenhouses before, but didn't elaborate.  So let me here.

First off, you have to maintain your heater.  If it's gas-based, you either have to have a line run or, more realistically, you have to change tanks.  Probably at least weekly in the middle of winter for even a little greenhouse - a tunnel of any relevant size without added insulation, every couple days.  Changing tanks means getting them filled or replaced, too, so you've given yourself a new, frequent errand involving heavy objects and threading.    If your heat is gas, you have to worry about CO.  If your heat is electric, you have to worry about short circuits.

To try and save heating energy and get more sunlight, you may want to install reflective backing and insulation.  You may also want bubble wrap or other clear insulation for the clear glazing.  But everything you add to your greenhouse is another thing that can get damaged, mildew, or get ripped off by wind.

You have to maintain your ventilation system.  Well, first you have to install it.  You can do on-the-cheap ventillation systems, like solar powered vent fans, but they're more likely to go awry and more likely to leak hot air when you don't want them to.  If your ventilation system screws up, your plants can fry in no time.  Even with a vent system it'll probably get too hot in the summer, so you need to leave the door open.  But in spring and fall you need to keep opening and shutting it as the weather shifts, and if you mess up, you lose your plants.

You'll probably want to even out day-night temperature variations with water tanks, and maybe fans moving air past them.  One, it's not as effective as you'd hope.  The thermal mass usually isn't enough.  Secondly even sealed black plastic buckets full of water need maintenance.  Not kidding!  They'll eventually algae up if you don't treat the water and ultimately turn into fetid cesspools.  If you add too much bleach or whatnot to prevent algae growth at once to reduce maintenance, you destroy your buckets over time (even plastic).  I've done both mistakes!

You have to deal with wind and hail damage.  These in extreme cases can outright total your greenhouse and everything inside.  If they don't, they can still damage it.  The process of sealing up the cracks becomes harder and harder each time.  In the winter, you also get snow damage.  Also, snow or ice can block the sunlight.

If you get a steel or wooden greenhouse frame, which covers most options, you have to worry about rust and/or rot.  They will happen.  If you use a sprinkler system, they'll happen 5x faster.

The door is often a weak point on plastic-skinned greenhouses.  What do you do when the closure mechanism breaks?  Try to jury-rig a soltuion?  See the "harder every time" problem.

Note that every modification you make to your greenhouse, every hole you put into it to run a vent or a hose or a cable, everything you attach to it is a pain waiting to happen.  *And* I should add, it's very hard to bond anything to greenhouse plastic (esp. polyethylene).  Annoyingly difficult.  I'll go ahead and tell you that 3M High Strength 90 is your best bet, but even that is far from perfect.

All of those openings (and yes, you must have openings!) mean insects get in very easily.  You always have to worry about things like mites and aphids, but in such an outdoor greenhouse, you can even get big bugs like tomato worms.

If you think humidity control is difficult inside, try outside.

Greenhouse plastic, by the way, needs to be changed regularly.  Untreated polyethylene won't even last one season before becoming brittle and opaque.  Treated polyethylene is good for one season.  Treated polypropylene is good for two, maybe three at best.

I could keep going, but you get the picture.  I've done an outdoor greenhouse in a cold, windy climate before, and it's a huge pain.  If you *can* do a grow room, I strongly recommend that over a greenhouse!

[samuelforest]

You definetily scared me If it is so much pain I won't buld any. It not for me. I like grow rooms because it is a control environment. I guess if I build one with glass and everything it won't be a problem, but I don't have the budjet for that....

[CoPlantNut]

Samuel,

I have had success with growing plants under lights, but the biggest plants I have under the lights are 5 feet tall.  In the past I grew some that were 8 feet tall, but the bottom 4 feet was just leafless trunk because the light couldn't penetrate down there. I discovered long ago that for growing plants indoors it makes sense to keep the plants as short as you can for many reasons:

-Light penetration if using artificial lights.
-Getting the plants in and out of doorways.  At some point you'll get spider mites or scale, and unless you can spray your plants in-place in your house or grow room, they'll need to go outside to be sprayed...  They had better fit through the door.  Tipping them sideways to get through doors gets to be more of a pain as the plants get larger and heavier.
-General maintenance.  Without the trees being exposed to rain and wind, you'll need to dust the leaves, pull out dead leaves, check all the leaves for insects, etc. and this is much more of a pain when you have to get out a ladder to reach the top of the tree.

I currently have a 12 foot tall fig tree (F. benjamina, non-fruiting) in my living room; it is nice looking but a major pain to take care of.  Every time it needs to go outside to be sprayed for insects or just given a shower to wash it off, I have to trim major limbs off it to get it through the door (or just after I get it through the door and the limbs have snapped off).

I'll agree with Karen that a poly-tunnel in a cold, windy climate isn't worthwhile, at least not for tropical plants.  And everything she said about greenhouses is true as well...  I think it is a matter of scale (number and size of plants being grown, not the insects) as to what makes the most sense.

I'm pushing the limits of what a plant grow room can do.  I have enough plants that they create humidity on their own, enough to be a problem even in my basement with a concrete floor and no drywall.  I want to (and do) grow things that require high humidity.  I've watered pots sitting in saucers for 3 decades and I'm sick of emptying the saucers if they get too full of water, and cleaning up spills.  So my plant room has many of the same complexities that a greenhouse has, and if I want to scale up even more I'll have even more of the typical greenhouse issues.  My current plant room also cost about as much as a similarly-sized greenhouse to construct.

I'd completely agree that for a reasonable number of plants, a grow room is cheaper and easier. But as you keep getting more plants eventually a greenhouse becomes comparable to a grow room in complexity and cost.  I will say that I am currently very happy with my grow room, but I want more light in it.  In order to add more light I'll need more ventilation, humidification, and possibly a heat exchanger which utilizes my ponds outside.  It never ends!

I'm really just waiting to win the lottery, so I can build my dream house with massive greenhouse (semi-attached to avoid having to walk outside in the cold to get to the greenhouse, but not completely attached to avoid humidity problems) and not have to work any more so that I have the time to take care of it all.  Unfortunately I took too many math classes in school and don't buy lottery tickets, so I guess I'm in for a long wait. 

   Kevin

[samuelforest]

-Light penetration if using artificial lights.
-Getting the plants in and out of doorways.  At some point you'll get spider mites or scale, and unless you can spray your plants in-place in your house or grow room, they'll need to go outside to be sprayed...  They had better fit through the door.  Tipping them sideways to get through doors gets to be more of a pain as the plants get larger and heavier.
-General maintenance.  Without the trees being exposed to rain and wind, you'll need to dust the leaves, pull out dead leaves, check all the leaves for insects, etc. and this is much more of a pain when you have to get out a ladder to reach the top of the tree

Tip, tip, tip the mango tree! It is already 5feet tall and it was 7 feet tall before! Kevin, do you wash your plants with a soap to kill insects? What do you recommend me to buy? I'll give a shower to my plants before bringing them in.

I currently have a 12 foot tall fig tree (F. benjamina, non-fruiting) in my living room; it is nice looking but a major pain to take care of.  Every time it needs to go outside to be sprayed for insects or just given a shower to wash it off, I have to trim major limbs off it to get it through the door (or just after I get it through the door and the limbs have snapped off).

It is huge! Mine is only 1 foot tall and I always keep it in. I'm scared to burn its leaves. It was a cutting from a friend's tree which is only 5 feet tall, but about 6-7 years old. How old it is?

My current plant room also cost about as much as a similarly-sized greenhouse to construct.

Your grow room is the best! That's why it cost so much It is so perfect that could not find any bad sides

I'd completely agree that for a reasonable number of plants, a grow room is cheaper and easier. But as you keep getting more plants eventually a greenhouse becomes comparable to a grow room in complexity and cost.  I will say that I am currently very happy with my grow room, but I want more light in it.  In order to add more light I'll need more ventilation, humidification, and possibly a heat exchanger which utilizes my ponds outside.  It never ends!

Hopefully I'll stop buying plants before!

I wish you to win the lottery

[CoPlantNut]

-Light penetration if using artificial lights.
-Getting the plants in and out of doorways.  At some point you'll get spider mites or scale, and unless you can spray your plants in-place in your house or grow room, they'll need to go outside to be sprayed...  They had better fit through the door.  Tipping them sideways to get through doors gets to be more of a pain as the plants get larger and heavier.
-General maintenance.  Without the trees being exposed to rain and wind, you'll need to dust the leaves, pull out dead leaves, check all the leaves for insects, etc. and this is much more of a pain when you have to get out a ladder to reach the top of the tree

Tip, tip, tip the mango tree! It is already 5feet tall and it was 7 feet tall before! Kevin, do you wash your plants with a soap to kill insects? What do you recommend me to buy? I'll give a shower to my plants before bringing them in.

Yes, every fall I spray my plants twice before I bring them back inside.  I use neem oil or Sunspray horticultural oil, mixed with a little soap.  Soap alone doesn't kill scale very well; oil seems to be the best non-toxic spray I've found that kills spider mites, scale and aphids.  I spray them 10 days before I bring them back inside, then again on the day they come in, to make sure I've killed as many things as possible and gotten full coverage.  Even then, there are still outbreaks of insects over the winter; having to haul plants outside or into my shower in the middle of winter to be sprayed was one of my big complaints with my previous plant room designs, so I made my current one water-tight and separately ventilated so I could spray plants in the plant room without having to haul them out.  (It works great!  I've had to spray 5 times in the room in the last year.)

I currently have a 12 foot tall fig tree (F. benjamina, non-fruiting) in my living room; it is nice looking but a major pain to take care of.  Every time it needs to go outside to be sprayed for insects or just given a shower to wash it off, I have to trim major limbs off it to get it through the door (or just after I get it through the door and the limbs have snapped off).

It is huge! Mine is only 1 foot tall and I always keep it in. I'm scared to burn its leaves. It was a cutting from a friend's tree which is only 5 feet tall, but about 6-7 years old. How old it is?

Yes, as you can see this tree is a challenge to get outside when I need to:


It is about 20 years old.  For the past 12 years it has only received light from 2 skylights in my living room.  It needs to be taken outside, trimmed severely, root pruned and repotted, and given a shower to clean the leaves off...  But that takes many hours and can't be done in full sun (since the tree isn't used to it) or when it is too windy out.

Hopefully I'll stop buying plants before!

Good luck with that!  I think that along with most of the people on this forum you will always want more plants.

   Kevin

[amaqeq]

growing in closed spaces has its good side as well
many pests mentioned here are easier to control inside
and bigger ones wont get in so easily
sometime if you want to keep organic you might want to use preventative neem oil
spray or cheaper summer\ultrafine oil to protect your plants from fungal infections
organic copper based fungicides are also available and may be used as curative and preventative measures for few(not all) common fungal diseases on many tropic plants
by no mean i suggest an infection will occur
 
grow room don't need you to be very handy
If you want to get the best advice on maintaining or building grow room
the aces in that subject  are marihuana growers who brought grow rooms operations
to merely perfection there are few forums, very friendly people as you can imagine
the only difference between you and them is that you do not have any illegal intentions
everything else is very similar: ventilation, lighting, heating, moisture, co2 levels
usual pests management

about energy consumption (mainly lighting in grow room)
the police wining card against illegal growers is the growers high energy bill
so seriously bring few neighbors in to show your mango tree as an preventative measure
most usable and cost effective lights are metal halides, sodium discharge (per durability and energy consumption)
these are two main types with different chemistry and different wave length

newest high end led lights like cree xml, Luminus sst-50, sst-90
can be bought in different wave length but all together I wont recommend them

florescent light is cheaper to buy but not so efficient

investment in metal halide lamp and starter/ignitor can be seen also as an investment in heating source
 
with few things told about poly tunnels made of galvanized steel as support
I can agree, but few facts are wrong and occur when faulty materials are used
or when good materials are used in a faulty way
 
If the space will grow small on you in a year or two
and you will decide to move out than by all means ask and I'll explain it more thoroughly
hypothetical arguments and over advising are good to help one make his mind
but you seem to successfully pass that point

one more thing: digital hygrostat is meant both ways same as thermostat
to maintain certain conditions by controlling high and low
for every high or low some kind of device is needed to be connected and carry out
the signal
mostly humidifying(humidifier)  and De-humidifying(dehumidifier)
if you do not want to buy dehumidifier lower temp and air circulation will lower humidity

heating(light and heating) and air conditioning
again air circulation will help at least in winter to lower temperature if the light
is heating to much

to avoid fungus gnats in soil-less mixture just cover the top layer with perlite or vermiculite (or any other mineral based solution)


it is a challenge with coping and potential for a lot of joy
have much fun with it

[samuelforest]

Your not the first person to tell to show my stuff to the neighbors I'll sure show them when my plants will be inside. Looks like it is really complicated to grow tropical plants...I did grow some last year under grow lights,but I decided to build a big grow room. First thing I do tomorow is buying some neem oil!