Dan Chiras

Marco Benito wrote:I built a walipini once in Santa Fe, NM.  Turned out to be a massive undertaking to dig a 30'x50' hole 6ft deep.  Unfortunately I lost all the pics with the inevitable computer crash.  Bummer.  Be that as it may, I'm still in the passive solar game with regard to putting up one these greenhouses.  My next attempt will be one of these, or one that GERES designed for the trans-Himalaya region.  I would love to see what Dan Has to offer that is different or better than or in addition to the designs I have seen.  Looking forward to the discussion.

Marco,

I would love to hear about your experience building and operating a Walapini.

I would be delighted to talk with you by phone and in turn answer your questions about Chinese Greenhouses.

This week is absolutely crazy but things settle down next week. Perhaps if you are interested we could chat about a week from today?  You can text me at 636-303-9884 if you are interested.

Thanks

Dan

Janet Reed wrote:Welcome Dan...have worked in many production greenhouses and have been in some earth sheltered.  Could you explain banking of heat?  And give an example of blankets you would use in a below .32 degree temp?  

Thanks
J

Hi Janet,

I just realized that I forgot to answer your question about insulation blankets.

I’ve been using a product called Aluminet which is  a UV-protected polyethylene material that’s aluminized. It’s a sunshade or sunscreen in the summer but also does a great job and blocking the escape of infrared radiation during winter months.

You mentioned that in your area Temperature drops to -32°F. That’s a pretty challenging climate to grow in, as I’m very sure you know.

I suspect you have to use a much more robust form of insulation to keep a greenhouse  warm in the dead of night in the dead of winter. I’ve never used it for this application but I think that the reflective insulation might be your best bet. Be challenging to roll up during the day. Maybe some other readers have suggestions they might share with us?

Janet Reed wrote:Welcome Dan...have worked in many production greenhouses and have been in some earth sheltered.  Could you explain banking of heat?  And give an example of blankets you would use in a below .32 degree temp?  

Thanks
J

Hi Janet,

Heat banking is a way of storing excess solar energy usually for the short term. For example excess heat that builds up in a greenhouse on a cold but sunny winter day, rather than being vented to the outdoors which is customary in many commercial greenhouses, can be stored underground in a climate battery. That’s nothing more than some thermal mass like a rock bed that holds the heat and then releases it at night.

That’s an active form of heat banking requiring ductwork and fans.

Thermal mass like concrete walls or adobe walls inside a greenhouse provide a way to passively bank or store heat. They absorb excess heat during the day and then release it at night helping keep your greenhouse warmer.

I Explain how these work in my new book.

There are also ways to store heat over the long term. This is a new area but a lot of people are having success storing surplus summer heat in underground storage areas for use during the colder months of the year.

Andrew Cegielski wrote:Hello Dan! Have you ever built a geodesic greenhouse or thought about it? I'd love to hear your thoughts. Cheers!

Hi Andrew,

I’ve never built a geodesic dome Greenhouse but I’ve been in a couple. They’re pretty cool. They’re a bit over glazed though for winter growing.

Wendy Boardman wrote:Welcome Dan Chiras, Author of The Chinese Greenhouse! Can't wait to learn what exactly a Chinese Greenhouse is. I haven't heard of this before.

Hi Wendy,

Chinese greenhouses are specifically designed to grow warm weather veggies like cukes and peppers and tomatoes thru the off season using only solar energy.

They rely on several key design features: east-west orientation, earth sheltering, insulation, air-tight construction, thermal mass, and solid walls on the north, east snd west sides.

They are designed to allow the low-angled winter sun to enter, this providing solar energy needed to heat the greenhouse naturally snd provide light for plants to grow.

I’ve explained more in some of my previous posts.
So it might be worth perusing some of them,

I will say one more thing: I built one and have been growing in it successfully in east central MO for several years.

My new book is full of good info for those who want to know more. What’s cool is that many of the ideas can be applied to conventional greenhouses as well to heat them affordably in the winter.

Dennis Barrow wrote:I have a 16 foot long by 8 foot tall cement retaining wall south facing just off the end of my home.

Researching passive greenhouses I keep finding Chinese greenhouse pictures.  Not sure how different they are.

My plans are to paint the retaining wall black and build end walls with haybales.  Clear plastic roofing for the south sloping wall.

My homestead is next to the continental divide just outside of Helena MT. (3 miles to the Divide)  Lots of sunshine here, but plenty of snow, wind and cold also.

I think this book would be very helpful in my planning and building my greenhouse.

Hey Dennis,

It sounds like you could pretty easily convert that retaining wall to a Chinese greenhouse. I think you’re well on your way to achieving that goal.

One thing you might wanna do is install it internal insulation in the greenhouse. We use aluminate shade cloth su in our greenhouse. It’s designed to keep greenhouses cooler in the summer but also helps hold heat in during the winter. You’ll very likely need that in Montana to keep your greenhouse from getting too cold at night.

I’d highly recommend you consider poly reinforce polyethylene for your greenhouse. It comes with a 10 year warranty against UV damage and works extremely well. I’ve used it for many years in the foothills of the Rockies in Colorado. It’s very durable too.

You might also want to look into some other strategies for storing excess heat generated on cold but sunny winter days in the floor of your greenhouse. This is a technique all daily and turn the heat back in.

I discuss several strategies to hear with solar in my new book which permes.com is featuring right now. You might find this information very useful to make that greenhouse work better.

Jimmy Burt wrote:I live in Oklahoma, so we do not get extreme "Northern" winters here, but we do get a lot of nights in the teens and even down to single digits a few times each winter.  I just recently purchased a Hoop bender to turn my old chain link fence top railing into Greenhouse ribs.  I am weighing my options between the less expensive poly wrap and possibly something better like ETFE film.  I am hoping this hoop house will serve me for several years while I work to build a more long-term Greenhouse that will likely have Insulated North, East and West walls, if not even earth-bermed walls.

I have looked at lots of different possible ways to heat my hoop house, but before I try something I have never done before and end up learning "the hard way" I would much rather ask advice from folks who have already be down this road or one similar to it.  I do not plan to run a Propane line into the greenhouse to heat with.  I may consider some form of small heater on a 5-10 gallon propane tank for emergency overnight help, but would prefer suggestions that are more sustainable than Propane.

I have looked at various configurations for earthtube, and I do have access to a Backhoe to make the digging a lot easier, and we have good sandy loam here, without much rock, so digging is not an extreme problem, as it may be in some places.  I have also looked at a couple different Rocket Mass Heater applications that seem plausible.  But whether or not I have looked at or mentioned an idea doesn't matter, because I KNOW that I am (at best) a Newbie extraordinaire.  

So please, offer met suggestions for heating my greenhouse.  I do have plenty access to firewood, although I would prefer not to be setting an alarm to go out to the greenhouse overnight if possible.  Please educate me on what my options are.

Thanks in advance for your advice!

Hi Jimmy,

Personally I’d strongly consider two earth cooling tubes run six feet under ground. I’d recommend run lengths of at least 100 feet and six inch PVC.

As you know, they will heat outdoor air to ground temperature of about 50 degrees F. This will help warm your greenhouse.

I’d also recommend earth sheltering and insulating the greenhouse. Although that may be a project you’ll complete in years to come. At the very least be sure to insulate the structure at night—that is, install Aluminet shade cloth that you can pull into place at night to hold the heat in.

It does a great job of reflecting infrared radiation that’s trying to escape from your greenhouse at night back into the greenhouse.

My book on Chinese greenhouses describes a number of other steps you can take to keep the greenhouse warmer at night.

If you just want to grow lettuce and other leafy vegetables throughout the winter, I’d strongly recommend you employ the Four-season harvest technique. All you need to do is install mini hoop houses over your grow beds within the greenhouse.

Lisa Rokosky wrote:I have Dan Chiras' "High-Performance, Off-Grid Chinese Greenhouses" (2016, spiral-bound) book. How does this differ from this new book?

Hi Lisa,

The book you purchased was self published. I published it so I could get the information out as quickly as possible. Since then I’ve built a Chinese greenhouse and have operated it through three winters. I’m just starting season 4.

This has given me a lot more experience and knowledge about the greenhouse.

With all this new information, I entirely rewrote my self-published book and updated figures, facts, and virtually all the information. I rearranged a lot of materials, cleared up some fuzzy sections, added mew photos and drawings. I basically did a complete rewrite on the book to make it more informative and to include all the new information I’ve gained.

Since you’ve purchased a previous edition I’d be happy to sell you one of the newest editions at a substantial discount. If you are interested, text me at 636-303-9884

danny doud wrote:Welcome, I am soon to build a greenhouse like this attached to my shop. I want to learn the best way to heat in mild zone 7 winters to support the current aquaponics system I will be building around. I am thinking of the buried pipe and black water filled barrels.

Thanks for putting out info to help us, Danny

Hi Danny,

I’d strongly consider incorporating thermal mass in the north-facing wall and floor and a short-term heat banking system (climate battery) under the floor to store excess heat generated on sunny winter days. Be sure to insulate the greenhouse at night. There’s a lot more to it but the idea is to build an air tight, highly insulated, highly massed structure.

I explain the various measures you can take to build an above ground Chinese greenhouse.

Hope this helps!

Dan

John Devitt wrote:Welcome.
Is it better to go east-west or north-south with a greenhouse?

Hi John,

If you want to grow year round in a greenhouse I highly recommend an easy-west orientation.