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Rexburg, Idaho ([email protected] )

I'm not talking about the makeshift PVC/rebar and plastic most of us use but rather the real McCoy. The ones with steel frames, built in heaters, exhaust fans and all the bells and whistles. Does anyone grow pumpkins in these? The biggest variable most of us have is weather, wind, hail, rain, cold nights, late spring, early winter, etc. etc. It seems to me that using a "real" greenhouse would eliminate many of these problems. You would lose a little sun intensity and may increase problems with PM but it may be worth it. I have not heard of anyone doing this but would be interested in talking to someone who had or someone who has grown other plants in a similar environment.

9/13/2005 11:42:25 PM

[email protected]

Brian
Check out my Diary, I've got 5 honest to goodness greenhouse, only thing I don't have is heaters, but they are going in this winter.
Also I believe Tremors put up a greenhouse
I'll help ya all I can with any questions.
The biggest problem is sun intensity, it seems to magnify the suns rays, so I use shade cloth.

Eddy

9/14/2005 12:44:22 AM

Ljubljana, Slovenia

In my experience, a "real" greenhouse would costs enormous amount of money: maybe the one they use for simulating a station on Mars would do it..

9/14/2005 4:31:50 AM

[email protected]

Our greenhouse is "convertable" in that once the main reaches around 12' I roll the cover open & let the vine "escape". Thus I have no need for shade cloth since the vine is out before the sun gets too intense. Growing entriely inside (larger house) would be better I think. The key is good quality environmental controls.

9/14/2005 5:19:15 AM

Cornwall UK.(50N 5W)300ft.

Hi Brian,

Not sure if you're meaning glass greenhouse or just real polytunnel as opposed to homemade.I used a real polytunnel for the first time this year,I did get faster growth although it got to hot in late June/early July.

Our British record was grown in a glass greenhouse and rumour has it that they ...well its just a rumour so I won't say any more.They are a fair way North of me.
Checkout out the Mere Brow Pumpkin website on the links page here.

I know you got frost to deal with but it would be very hot in between.

Mark

9/14/2005 11:44:08 AM

Rexburg, Idaho ([email protected] )

Just looked at Eddy's greenhouse and this is getting close but in my climate heaters will be required. A typical poly greenhouse without heaters will not provide a lot of insulation at night. Double layer of poly with blower to inflate the inside space in between provides more insulation but at a cost of lower light transmission. Would be interested in knowing the inside verses outside nigh temps? My night time temps are low and need to be raised, July lows average 46 degrees. I would need about 20 degrees of "heat" at night. Steve I saw one picture of a fan in your greenhouse. How well does it cool the greenhouse?

9/14/2005 12:56:04 PM

Puyallup, WA

Brian,
Our July and August lows are frequently in the mid to low 40's. High's average 78°. 6 mil hoophouse plastic comes off about mid June.

9/14/2005 1:04:03 PM

Rexburg, Idaho ([email protected] )

In July I six nights in the 30's with the lowest 35.6 degrees (this is a normal year here).I can't help but think that the low night time temps are really hurting my potential. The highs average 87 degrees. This is probably also leading to many of the splits that happen in my patch. If I can raise the low temp and thus even the tempurature swings (average 41 degrees a day), hopefully not only will my growth increase but the splits decrease???

9/14/2005 2:49:09 PM

Menomonie, WI ([email protected])

If your high temps are 87 Degrees...you are going to have a cooling problem during the day. In which you will have to cover the greenhouse with shade cloth. Or invest in a misting system to cool with. Huge fans located in several areas. They have very good systems out there but the price is going to be high. Then what do you do if you loose power for a couple of hours or 2 days. Everything in the greenhouse fries. Some how you would also need something to retain the heat for warmth during the night.

9/14/2005 3:44:09 PM

Pocatello ([email protected])

Brian,

What we need is something you can open up in the day and
cover again at night. But then, I've found that the plastic
doesn't really retain heat once the sun goes down, so we'd
need heaters for the night. Sigh.

Easier said than done...lol

Cliff

BTW: Over on the fertilizing and watering area, I'm going
to start a thread on calcareous (buffered with natural lime)
soil. Maybe we can get people with this type of soil to
form a "support group", for lack of a better term.

9/14/2005 4:52:09 PM

Rexburg, Idaho ([email protected] )

They do make greenhouses with sides that roll up. This should allow for nice ventilation but exactly how good they are at retaining heat I have no idea. Heaters I think would be mandatory. But it will be hard to swallow the gas bill for heating a greenhouse in July!

9/14/2005 5:50:21 PM

Pocatello ([email protected])

I suppose it's possible, but not feasible, for me.

9/14/2005 5:53:24 PM

Eugene, OR

It sounds like I live in a similar climate as some of you colder weather growers. It may not be a true "greenhouse" but I have a setup like Cliff describes. The greenhouse completely enlcoses one of my 400+ sq. ft. plants. The roof rolls up so I don't have to worry about overheating during the day. As it starts to cool off during the evening, I close it up to trap some of the heat. Once it gets dark, the heaters go on to maintain the warmer temps.

I believe Eddy (ice-man) gets some pretty nasty cold weather up there and he has the closest thing to a true greenhouse that I've seen on this site. Jos also has some very nice examples.

We've had two frosts already and from what you described Brian, our weather is nearly identical. On the nights we received frost, the greenhouse temp. was at least 20 degrees warmer than ambient and it helps keep the temperature warmer for much longer than using no greenhouse. A "true" greenhouse with automated temperature and humidity controls would cost thousands and as much as I would love to have one, I make due with a lesser system and get similar benefits with a litte more work. Here's a pic: http://www.bigpumpkins.com/Diary/DiaryViewOne.asp?eid=42037

9/14/2005 6:01:12 PM

Eau Claire, WI

The real challenge with greenhouse growing is not heating at night but cooling during sunny days. As long as you have money for heaters and for heating bills (for a structure with minimal insulation), it is not that hard to keep nighttime temps reasonable. The problem is during the day when you want direct, unfiltered sunlight. It takes a sophisticated greenhouse system with extensive ventilation (ie. big fans or a retractable roof) to avoid stress from high temps. It is very difficult to keep the temps in my greenhouse below 120 degrees on a bright sunny day. If the power goes off, it will be 140 degrees + within minutes.

The second problem is that you become dependent on artificial watering. There is nothing better than rainwater for plants.

9/14/2005 6:23:29 PM

Ontario, Canada.

The Folks at Disney in Florida were doing this awhile back. They at the time got a few above 500 growing only in a underground hot tub sized pit of soil. I spoke two years ago with the greenhouse manager. He told me that growing AGP's indoors was an experiment for them. He was aware of BP.com and at the time he visited this site often but did not contribute.

9/14/2005 7:07:53 PM

Lloydminster/AB

Humidity control is the biggest problem. Overheating is the next biggest problem. Automate the doors and make them large. Pumpkins tolerate more heat in a greenhouse than they will outside,not sure why but I think the leaf temp is lower due to the slight shading effect. Leaves become very large and settle down causing some problems. It becomes a huge ordeal to weed. I have grown one plant in a greenhouse for the last 4 years and am just perfecting the system now. There is a learning curve, don't get discouraged! My latest greenhouse is homemade but is much the same as Eddy's. Still on a shakedown run!

Don

9/14/2005 8:47:53 PM

[email protected]

Try this again I just posted a response but it never showed up.
Anyway my night tems are about the same (45-50) degrees at night. The greenhouses stay about 10 degrees warmer than the outside without heat. 2 of my greenhouse are double poly with blowers, and 3 of them are a 12 mill woven poly. The double poly stays warmer longer. I am going to install wood burning heaters in 4 of the greenhouses this winter, I am also installing thermostatically controlled dampers to regulate the burn. From my research I should get a 12 hour burn with each filling, plus I get all the wood I need for Free. Plus I want the ashes for the groung prep.
I have a high low thermometer in each greenhouse and they record 6 cycles so i know when the hottest and coldest temps are. The Hottest is usually between 3:30 and 4:30 in the afternoon and the coldest is usually about a half hour before sunrise.

9/14/2005 8:57:35 PM

[email protected]

As Don said Big doors, Last year I had 6'6" X 6' doors and 2 fans couldn't keep up. This spring I changed the doors to 7 ft high X 8 ft wide and 1 fan was sufficient.
Humidity is tough but I found by watering in the mornings only (between 6 and 7 AM) the humidity at night is much less.
I made a mistake by placing my greenhouses 18 inches apart and when it rained, the runoff saturated the ground, I am going to install Drain tile around the greenhouses to solve that problem next year.
I like the contolled watering. I collect rain water and have 3000 gallons of storage

9/14/2005 9:05:31 PM

[email protected]

Brian,

That fan turns the air very quickly & thus keeps the inside temps right there with the outside temps on a hot day.

Steve

9/14/2005 9:56:56 PM

Napa Valley, CA

Takao Hoshijima and his wife Yoshiko both grow in a "Real McCoy" greenhouse in Japan.
Last year Takao grew his 918.4 (a new record for Japan) on the 1107 Cramer in his greenhouse.
I have seen photos and videos of his set up. His greenhouse is HUGE. Takao and his wife have been doing this for several years. It seems that they have learned to control the humidity and heat. Seems like we might be able to learn a thing or two from our Japanese neighbors on AG greenhouse growing.
George Webster - Napa, CA

9/14/2005 11:28:19 PM

Rexburg, Idaho ([email protected] )

Great Discusion!! Not sure I'm ready to make the plunge just yet as the price tag is substantial. But I honestly believe it is the only way to get a true monster out of my climate. An expensive greenhouse would still be cheaper then moving someplace else.(not really an option)
Eddy, What kind of fans are you using? I've seen large commercial greenhouses ventilated with two exhaust fans and two large shuttered intake. These would be easier to automate then doors. Cheaper then retractable roofs.
George, Would be interested in seeing that video any suggestions as to where I might find it?
Jim, I am totally dependent on sprinklers anyway. Seldom rains in Idaho. What kind of ventilation do you have in your greenhouse. I know in my cloches I can easily hit 130 degrees if I leave the doors up in the spring. A definate problem for relying on fans alone. One power outage and your season is over.
The automatic roll up sides may be an option but I need to talk to people who have these and see if they really work. They make models with 4-8 foot sides. That much open space along both sides should give adequate ventilation??

9/15/2005 12:14:18 AM

[email protected]

There is more to ventilation than just temperature control. Removal of gases such as Ammonia is very important. We've all seen the "aged oldest leaf" situation right? Look to see how old the leaves that were inside a cloche or coldframe look by August. A lack of ventilation & air circulation in May is the most likely culprit.

9/15/2005 5:09:50 AM

Cameron,ontario Team Lunatic

We grow our watermelons in a plastic greenhouse and take the cover off during the day. This allows the plant to get the benefit of full sun during the day and the plant keeps warm at night. Once the cooler weather hit in Sept we try to keep the cover on. In Canada it's hard enough to grow watermelons and the makeshift greenhouse works well for us.

Phil

9/15/2005 6:47:22 AM

[email protected]

Brian
I'll take a bunch of pictures on fans, blowers, etc tomorrow and post them, easier than typing lol.
Temperature inside can easily run up to 130 degrees in the greenhouse also, BUT, I thought this was bad, which it can be, but if you take a thermometer and place it outside in the sun on a hot day, it can reach 125 degrees. It really sounds worse than it is.
Don, I had noticed the same thing on the size of the leaves, I believe the plant is compensating for the lack of, or the less amount of sunlight, So I don't believe the shading or diminished sunlight is a factor.
Side Roll Ups. Can be and are great in the right application, The biggest problem with them is over pressurization in the greenhouse. If you have a west facing rollup and the wind is 20 mph from the west you will double the pressure in the greenhouse and this can cause structure problems, I set up greenhouses for clients out here and within 2 years we were back fixing the rollups and making the walls solid, That's why big doors on each end are great. On cool days you open half and on hot days you open both.
Also my fans are on a thermostat for the days I'm not around, I have them set to start at 95 degrees. On super hot days I make sure the doors get opened even if it's by a neighbors kid.

9/15/2005 10:12:05 AM

Napa Valley, CA

Brian,
Yes, I can make a copy of Takao's Japanese Atlantic Giant greenhouse video for you or any grower who wants one. The cost is $5 to cover the VHS tape and mailing, etc.
This is not a "how to" video but it does give us a good glimpse on how Takao and Yoshiko grow their pumpkins. It also shows their Weigh-Off and some other interesting stuff.
Anyone who is interested can contact me at [email protected]
George Webster - Napa, CA

9/15/2005 2:56:35 PM

Cologne / Germany

My father constructed a greenhouse in spring that turned out to be a winter garden somehow...aluminium profiles, thick coated windows, automatic ventilation and shading from outside. All for 130 sqft, 14 ft high. Works perfect for the price he had to pay...
Don´t let me think about doing this for a complete AG patch. But if you would like it perfect, that´s the way you need to do it. Everything else will just be of little help and might lead to serious problems during summer heat and humidity. Maybe remay instead of plastic stuff would be a good idea for a cheaper construction.

9/15/2005 7:09:47 PM

Netherlands

How much light does remay let through? Is it a better insulator than plastic? I would think so.

9/16/2005 2:14:47 AM