greenhouse question

Only b/c of DG and it's members giving great suggestions am I(DH) building my greenhouse this way.

As for heating... well, we used the thin corrigated stuff ($11 per panel) instead of the polycarbonate panels ($63 per panel) do the math. I plan on this not holding heat very well so we are going to put heavy duty plastic on the inside for the cold months. We are first sealing all the "seams" with silicone to help keep air tight. But I know I will still need the plastic. We are going to use oil radiators for heat. BUT, I am in the process of looking for black 55 gallon drums to fill with water for radiant heat. They'll go under the benches. This should keep the heat from coming on quite as soon. I hope to maybe next year put these panels on the inside instead of using the plastic to have a permanate insulating wall. The gap between the panels would be aobut 5 to 6 inches. DH wants to use the plastic this year sooo...
one more thing, because of the panels I did use, I know I will have to use shade cloth a lot sooner than had I used the "right" stuff.

pdoyle,

Don't knock yourself out putting black 55 gallon drums under benches.

I did some experiments last year with black containers under benches. The heat gained is minimal to zero...meaning the containers were nearly always right about GH air temperature.

The containers really have to be in the sun for any solar gain. And I go against the grain on this, but I don't really think they do much good by themselves, even in the sun. I will only go into the rationale for this if anyone really wants to hear it.

SB

Thanks stressbaby, I was hoping someone would pipe in on this.

working on the benches now.

other side, this side will have a portion of it recessed for a seed starting bed

another

One more, DH angled the ends so I could access the windows easily

Considering what we used for the walls and roof (the clear panels), how do I determine when I will need to use a shade cloth? We are still working on it. Doing electrical stuff right now. People ask me when I'm going to put plants in there. Well, it's getting really close and now I'm a little nervous. I don't want to put stuff in there and they burn up. Like to day, it is supposed to be in the mid 80's and sunny. Even tho it's Oct 3, all the windows are open (electricity is not on yet so the fans not working yet) and doors are open. Would I need a shade cloth at this time of year? I'm thinking I'm going to need something pretty much all year. OR b/c of the time year will determine if a shade cloth needed. Is that right? HELP ( Remeber now, these panels are not the polycarbonate/made for the greenhouse ones)

Since you will be growing indoor plants, I would say a shade cloth almost all year round would be needed. Even with 50% shade, those plants will still get more sun than any plant indoors.

You might consider something to diffuse the light a little bit. Light diffusion is important for health plant growth.

http://www.greenhousecatalog.com/greenhouse-light.php

I think that I disagree with SB here. I have houseplants ( and remember-what we call houseplants here -grow in full sun in the tropics -alot of them, and can take full sun in a grhouse -treated glass/plastic or not) that get all day sun inside and they are fine. I also have plants that require heavy shade outside (young tropical palms) that do great in the grhouse in full sun.
I don't think a shade cloth is necessary in the winter-that your plants will stretch and get leggy with a shade cloth. Also it will take longer for them to dry out with a shade cloth (of any kind) in the winter, and you really want your plants on the dry side through the winter. The winter sun is just not that strong

Maybe if you acclimate them they'd be fine in the winter without shade cloth. I have had some problems with my plants getting burned when I remove the cloth because they weren't acclimated. Tigerlily is probably closer to your zone than I am, I will respectfully defer to her.

I think I agree with tigerlily, also. Anything that's *really* intolerant of the sun, I usually just tuck away, behind something a bit larger (plant, bench, etc). This filters the light enough to create a happy medium for the plant. And, like she said, some plants that are considered "houseplants", such as my Ficus, do eggstremely well in the winter, with no shade cloth.

Sorry, SB. =)

In your defense, my greenhouse isn't out in the "middle of nowhere", like yours is. =) Which reminds me... have the cows chewed thru the hose lately?

lol that will be a first! 50/50 on who is right here pdoyle....except that i don't think that SB keeps alot of plants inside the house-do you? I have been known to , I unfortunately do not have either the restraint or common sense that SB has when it comes to saying no to tropicals! The below picture is what one of my hallways was like last spring after I ran out of room in a grhouse.

WOW! That’s the most inspiring picture I have seen on this forum since I joined!

Having just gotten serious about growing plants this year I have been overwhelmed by all the information required to build, equip, and maintain a GH. Not to mention the knowledge of actually successfully growing plants. I built a 12X14 GH in March of this year. Since then I have read several books, spent hours and hours on the net and this forum trying to gain the knowledge required to successfully grow something……anything!

One has to admit, this is a lot to absorb for a guy that spent all of his life twisting wrenches for a living. I have been in awe of the folks out here and all the knowledge and experience they have and are so willing to share.

Since I started this project I have learned many things like, Calculating BTU’s needed to heat the GH and installing the right size heater, Installing an evaporative cooling system to cool and humidify the GH, plumbing 3 separate watering zones and timers for different plants water needs, Installing Reverse Osmosis system for watering, etc, etc.

I also learned that plants don’t grow well in just plain dirt. So I learned you need a mixture of things like Sphagnum Peat Moss, Coconut Husk Chips, Cactus Mix, Pearlite, and TURKEY GRIT?? After reading Tapla’s essay on Perched Water Table in containers I was ready to run down to Wal-Mart and buy a bunch of mop heads.
I’ve also learned how to spot Mealy Bugs, White Flies, Scales, Spider Mites, Root Rot, Sooty Mold, Rust, Aphids, Leaf Miners, and a host of other critters.

I have learned a lot about fertilizers, what the numbers indicate. What kind to use for different plants etc. I am still trying to grasp things like what to use Epsom Salts for and where to buy Dolomite Lime, and what I should do with it when I find it. I am still reading about Macro Nutrients and Micro Nutrients. Don’t know exactly when they should be applied, but got some anyway and have been adding them to my watering routines.

All of this so I could grow some plants! I have been trying, and have had some success and some failures. But when I saw that TigerLily had plants that actually had some leaves that were discolored and had some brown tips, WOW! That was encouraging, I have plants that look like that too!!

I guess I won’t give up yet!

Thanks to Digital_Dave, Stressbaby, Tigerlily, Eggs_Zachtly and all the other experts out here that have given so freely of their time to educate those of us that want to learn how to grow things, whether it be for pleasure or profit.

I really am enjoying the GH, and as so many people have expressed, my only regret is that it is not bigger.

Nautical

Thanks Nautical! It is a great love to have-it keeps giving and giving. I always admired mechanics myself. I think it would be so cool to understand the workings of an engine, and esp to be able to fix it. Solving a problem with a plant is very similiar, in some ways to diagnosing a problem with an engine.

All those brown tips and leaves that you see are actually normal for those types of plants. Bananas and gingers do that in the winter when they are in semi-dormancy. They don't look like that now, but they will again in a few months if I take them out of the grhouse like I had to last winter. I got desperate and put a large tarp on the floor for a bunch of them, and just dragged the hose in through the door to water them. This year I got a few shelves to put my small palms on instead of the tarp. I got real tired of that setup at the end.

nautical said:

Good one E-Z! Thanks everyone. I appreciate everyone's input. Hearing different things gives me the ok try it - what ever that may be. I think I will start with the plants that have been outside in full sun all summer first. Once they're in and seem to be doing ok, I'll "tuck" in the ones that need more shade like E-Z said.
dawn

Nautical, are you dissin' my TURKEY GRIT? ;-)

Been a little slow lately. Had to take care of other things. Here is where we are at.

work shelves are done

Other side, the pipes are what we are using for hanging plants on up top. This is where I will either use as a seed starting bed or potting spot.

Looking in toward the house (west)

Because we put windows in I had a problem with opening the doors and leaving them open. When I opened them all the way, they blocked the window (air flow). I had to figure out a way to be able to leave the doors open and not block the windows. DH figured it out for me.

DH put elec sockets spaced out on either side, one above for lights. The fan is now on a thermostat so i can leave it on. I have a few plumerias in there b/c I know they like it hot and can handle it. Cooler weather is around the corner so I'll be adding more. Those water barrells on either side will come in handy. We have had hardly no rain and what we have had I've been able to collect in the barrells. DH is going to do something so I can use the water in them and not lug water all they way back there. Well point is on my wish list.
Not sure what to do about the floor. It is uneven b/c it was never really correctly leveled. Kinda drove the tractor over it to pack it down and never went back to it. It's not too bad but is uneven. I thought about putting pine straw down and let it go. Someone told me that wasn't a good idea. Forgot why. Any suggestions? (cheap suggestions)

I know it is hard work, but you could just use a hard rake and a shovel and move the high spots to the low spots. Once level maybe a thin layer of pea gravel just to even things up a bit.

Of course I am not the one doing the raking and shoveling........so easy for me to suggest eh?

I am sure other folks here will have far better suggestions.

Nautical.

I remember a post saying that mulch on a floor (possible pine straw too?) could be a breeding ground for fungi, mold, and other nasty stuff.

We put down gravel, and splurged on some 12" square concrete pavers for the walk areas. Of course, my gh is much smaller! You could always add pavers later. We found gravel wasn't very expensive if we took our pickup to a local landscaping rock yard and let them load it. Buying gravel by the bag at the box stores would have cost a lot more.

Of course, once it's in the truck, somebody's gotta shovel it out again into the wheelbarrow (groan.)

I also read that really small pea gravel can be annoying if it gets stuck in your shoe treads, so I tried to go for something just a bit larger.

Your GH is looking great!

I would definitely use gravel-if you don't, it is going to be mudcity in there! I hate walking/working in mud...

If you are going to use that fan that you have, I think your air flow is going to be better if you close the doors while it is on. and even just have the windows half open. Test it and see what gives you the best air flow. I know that when my door is open, it cuts down on the airflow.

Tigerlily123, if I closed the doors and windows(almost) as you suggested, wouldn't it get too hot in there? When I first got the fan in I did close everything and crack one window on the backside to see how well it pulled the air and it did really well. I just thought that if it is closed up like that, it would get too hot even with the air flow. Even on a hot summer day? Well, now that I think about it, most GH don't have windows do they?

As for the floor, what you see is what we have here for dirt. CLAY!!! I should have finished it when it was first dumped (I know) but I wanted to get started on the GH and told myself I'd come back to it. Now it is rock hard. All I can do it "chip" at it. I tried to skim the top off and it comes off like a fine powder. DH suggested wetting it and then try moving some.

You may have to experiment some with air flow and how open you leave the windows but I think that people who have vents at the top and shutters both open at the same time get less draw than just the shutters. The problem that you will have with windows instead of shutters is that with shutters-when the fan comes on, it will automatically open the shutters, and they will close when the fan is off. You will have to come out every am and open the windows and then remember to close them at a certain each late afternoon so that you don't have cold air coming in the grhouse once the fan shuts off. I, personally would switch out the windows for shutters-otherwise someday you will forget (or can't) to open/close the windows and you will either waste heat or not bring the temps down enough during the day.

Why are you trying to move the clay? Just dump a bunch of gravel on the floor and rake it out to make it even. Take the easy route, I say! The clay is dry now, but once you start to water in there, it will turn soft and go to mud.

I think gravel will be the answer too. DH framed out a spot on the other end for a vent with shutters. He even said he thinks it will need this. That way I won't have to worry about the windows. If/when I get the vent in, I would leave the windows either open or closed all the time.

I found that an evaporatine cooler was required to use the greenhouse
mine is on a thermostat and it is 75 degrees outside now
and the cooler is running now as the greenhouse will quickly get to 90 degrees
I have been told most plants prefer temps below 75

http://www.rader.org/garden/cooler.htm

jimrader, that is on my wish list too.

Well, I have been closing up the Gh at night b/c the temps are dropping to the low 40's. I went to open the doors this am (5:45) on my way to work and the temp inside read 42. The temp on my car read 43. So it is not holding heat at all I guess. Shouldn't it hold something? It gets warm in there during the day. I guess I'll be lining the inside with plastic sooner than I thought. Somebody PLEASE tell me this will help ALOT.

my greenhouse is 4mm twinwall polycarbonate with a second wall on two sides. which would make it quad wall with a sheet of 6 mil plastic and a couple inches of dead air space between the two layers of twinwall. the gh is attached to my house on 2 sides. It has a thick concrete floor

It has an over night low which is 5 degrees warmer than than the overnight low outside without a heater! so I would not expect much heat retention.

the outside lows are running as low as 41. the electric heater keeps it above 55

On my small twinwall polycarbonate GH, there is also no heat retention at all. Unfortunately, they need to be heated at anytime of the year where there is the remotest chance of frost, or temps dropping too low for your tropicals. Lining the walls with plastic should help a lot when trying to heat the GH, though it still won't retain heat without some kind of heater. I am wrestling with the idea of putting major money into a larger (8X18) lean-to GH, that I would heat year round or a stick-built sunroom with an insulated real roof. I'm leaning towards the sunroom, because I'm afraid that here in VT, the heating costs would just be too high for a year round GH.

Thanks for the feedback. I plan on using 2 or 3 oil radiator heaters. They have thermostats. I just didn't plan having to use them so soon. I guess I thought it would hold heat longer. Right now, I am making sure it is sealed good. Only had 2 nights where it got down in the 40's so far. This week it's been in the 50's at night so I've had time to work on getting it more air tight. My goal is to keep the temps above 45 in the winter. Think that is realistic? If the elec bill turns out to be too much, then I'll be moving my plants back in the house.

Well, I put one heater in there last night. I went out to ck the temp this morning, it was 40* inside. Now the thermometer is up & near the wall (panels) and at the other end of the GH so I know it had to be warmer away from the walls. It didn't feel that cold either. I didn't linger as I had to go to work. I need to stop by the store and get about 2 dozen more cheap thermometers so I can put them all over the place to get temps in different areas. (Well, maybe not 2 dozen). I did buy a remote digital one that has a base kept at the house so I could read the temps inside & out of the GH from my kitchen. That didn't last a week. I think it's too far from the GH (said it would read up tp 330') The GH is about 200' from the house. Then at night it wouldn't read ( I guess it got too dark?) Then last but not least the LCD went out in the remote part in the GH. I think the sun got to it. Any reccommendations on one?
I need to take some more pics. Got shelves up on one side. Got some plants in there too. Gonna have to take the plants out now to put up the plastic.
One thing I'm going to do is place my plants in order of cold hardiness around the GH if I can't get them all in the middle.

Does the following apply to most greenhouse plants ?

Recomended GH low temperatures.

temperatures should be kept between 57 and 95 degrees
temperatures below 57 will stop growth
They can be exposed to lower temperatures down to the mid 30s without experiencing permanent damage

source
"Bananas you can grow" by Stokes Tropicals Publishing Co

In many cases of tropical or subtropical plants, yes. Look at the example of citrus. "Absolute Zero" for citrus is 54F. Below that temp, the roots take up no water or nutrients. They don't die, they just don't work. Now, if you take that plant and put it in the south end of a GH, and the sun hits the leaves in the morning and they try to fire up the photosynthetic engine, they will have no fuel on which to run. This is the source of the dreaded "winter leaf drop" that you see with citrus. The same phenomenon happens if yo bring a cold pot inside and place it in a sunny southern window in the house.

Because the plant water uptake decreases to negligible amounts at lowest temps, one must take great care with watering, and one must see to it that the potting medium is well-aerated and freely draining to prevent a persistent water table in containers which can lead to root rot.

Also, many plants in the GH slow their growth mid-summer to practically nothing.

At this point my goal is to overwinter the tropicals I have. In the years past I have kept them in the sunroom attached to the back of the house (east). I have read temps of 38* in there and they did fine. palms & ferns stayed green & bananas went dormant. I've run out of room so I'm going to try and do the same thing out there. Keep them from dying. I know I can't afford to heat the GH like the tropicals would perfer. I am going to put plastic up on the walls and roof. This is a learing process for sure. I still can't put all my plants out there for fear of losing them. I dont trust it... yet. :)

I run my grhouses at 60 degrees at night, and I still saw a lot of tropicals just sit there and do nothing. I think, regardless of temps-the sunlight amt-the shorter days in winter-has a huge part to play in it. I think that if I weren't actively growing other plants that need the 60 degrees, I would lower the temps a lot (well, I don't know how brave I would be-probably lower them every 2 wks by increments and see what happened).
Once the daylight increases (mid spring), then I see much more growth-and over the summer-outside-all the tropicals exploded in growth-

SB meant to say mid-winter in his last sentence instead of mid-summer. You all would have probably figured that out! lol