Design Your Greenhouse! Lean-away IS BETTER Than Lean-to! This Will Surprise You!




About: I am a stone mason. My hobby is making new solar cooking and gardening stuff. I have used solar heat to cook soil for a couple of years. In mother earth news in January, i read that their compost expert does...

 I got the basic info on the web, found the most suitable area on my site and started building. My glass was free and huge! and between that constraint and the site shape I ended up making something quite different!  In using it, I have found out that a considerable amount of direct sunlight in summer comes from NORTH of  the east west line!
So a typical south facing lean to greenhouse will fail to collect this light! 
Perhaps you can learn from my successes and mistakes and the tools I found online while trying to explain what went right.
This explains what I did, why I did it and why it works so well.
Information has come through during this project  that makes a compelling case for lean away greenhouses.

Step 1: Why Is It Lean Away?

The only thing I bought for this greenhouse was the silicone to put the glass in frames and the screws to hold the wood together.  Everything else, I had on site and was determined to use.   The glass was 4 ft by 6 ft, 5 sheets and my wood meant that I could  do 2 large frames and one small one.  The glass was so heavy that I was afraid if I leaned the big pieces, it could fall over as i worked with it.   It had the unusual shape so that it lined up with the fence at the side.  Once I put it on blocks to keep it off the soil, it was pretty high at the front.    Lean away was the only solution.!

Step 2: I Had a Few Unusual Construction Methods.

Biggest new thing I tried was buckets in the ground for some of  the posts.  This is mainly  to prevent termines and water from destroying them.  When i am happy with placement, I can add concrete or roadbase  in the buckets to keep everything steady.

Step 3: Evening Sun!

Because it leans away, the sun hits the plants over the fence rather well from the north east and northwest.  Recently I did a model that suggested that less than 12 hours of sunlight per day  comes from the south in summer. The CR4 engineering user "Usbport" initially thought that it was 12 hours exactly but he checked with  " starry night" and found around 10 and a half hours in late June comes from the south in his city! (Nottingham). Over 7 hours comes from the northern half there! 
This happens in the morning and in the evening.  It is this light that is far more effectively used by a lean away greenhouse.
I Include screenshots from sollumis from about 15 June, 15th September and 15th November to show how this is especially useful in summer!

Step 4: Lean-to Versus Lean-away. Angle of the Sun, Transmission and Reflectance

This is one of the big ones!  Here the lean away wins really well.   Glass transmits about 96% of the light if it hits it straight on but if it hits it obliquely, more and more of the light gets reflected instead of going through!
I have taken a graph from wikipedia and heavily changed it to try to show  this effect. Note that it is NOT  a linear effect!   This means that the lean away greenhouse is way more effective than a lean to at taking in the evening light.

Step 5: Internal Reflection!

One of the really big surprises is that the north east wall of the greenhouse gets light in the evening when the sun is coming from the north west!  Some of the light bounces off the angled east wall and some the front wall and hits the north east back wall from about 5 30 pm until about 8 pm.
This is an important and unexpected bonus.

Step 6: Gutters Behind

I improvised gutters and they are behind the greenhouse. Some panels of plywood is easily removed to clean them out, etc.  The water is stored in a barrel in the corner of the fences.

Step 7: Easy Door

The door presented a special problem to me because there were so many ways to do it!  I really like the idea of a sliding door but I just didn't have the hardware to do it.  All you need for an ordinary door is 2 hinges and the door itself.  But I had a sliding shower door instead of a real door. I ended up turning it upside down, taking off the sliding rollers and attaching it to a piece of 1 by 4 (that was not long enough) with just 2 screws.   through the only metal that didn't contain glass on that side.  I had to add another piece of wood (an off cut with a little v shape to it to contain the bottom of the door. Then I cut perspex (plexiglass) to fit the contour of the top and screwed that on too. (makes the door that tiny bit sturdier and I got one more screw in at the far side.  The final act will be to add silicone rubber where the shower door meets the 1 by 4 and that will keep it solid as heck!  Solid as a rock in fact! (Maybe)

Step 8: The Latch (most Primative Ever!) But It Works.

Just 2 screws and a piece of bent wire hold the door shut.  Again I had the special problem with the stupid shower door. If I drill into the glass, will it break? Anyway, this is an interim method to keep it shut until I think of something better.  It actually works pretty well.  One more screw or an eyehook would probably make this long lasting. It can be opened or locked from inside too/

Step 9: Extreme Growth!

Things sure move quickly in a greenhouse!  Today is 22nd of june,   On may 9th, I sowed  the stringless runner beans. The first of them were planted out on june 12th and the last ones  about 5 days ago. One was already over 4 ft tall when I transplanted it! They were where the squash seedlings are now. 22nd june.  The lazy housewife beans were transplanted out yesterday.

Step 10: 7th September Update. Productive!

Just a few screenshots from a little camera movie to show how well it is growing plants.  This is largely irrelevant because I do not have a  "control" greenhouse  that is lean to to compare it to.   Bur never the less.  Here it is anyway. I don't feed my tomatoes or fertilize them. They get water once or twice a day if they are lucky.  Sorry the pics are so blurry

Step 11: Watering

I had intended some amazing windowfarm type continuous watering system but so far it is watering can and buckets.  I have used large clay pots (these have one hole in the bottom) and I just add some soil to  the bottom of them.  The water has stayed for up to 4 hours. My soil has a high clay content.  I think metering out the water like that will help the plants get over the highs and lows of normal watering.

Step 12: Seasons and Greenhouse Design.

I expect to use this in winter too  but some people live in really harsh climates and would have to abandon their greenhouse over the winter.  Note if your winter is dull and cloudy  (like mine) or sunny .  This matters because direct sunlight is not so important  then.
Maybe wind shelter is more of a factor in some places, maybe double glazing will help some in winter but not others.
I think greenhouse design is much more of a niche thing that I had expected when I started!

Step 13: Learned and Noted and for Discussion!

First off, I never intended doing anything unusual. Most of this was 'accidental design".  Windows high and unwieldly and available wood a certain size so upright was easy and lean back was the only option.  Pie shaped lot so to have usable space beside it, I had to have the side of the greenhouse at an angle.  But it worked!   And seems to be working rather well.
On google images, there are thousands of  lean to greenhouse which lose out in the summer.   There are also greenhouses beside fences where you need to crouch to get into the darn thing!
Hopefully people can learn from this mistake of mine.
Hopefully we can be more openminded about greenhouse design.  make something that works well for YOU not someone in a different climate or at a different latitude.
We can use sollumis to better place our greenhouses and use  a lean away design if you find it works in your place.
Thanks  Brian

Step 14: Credits, Thanks for Help Offered and Given, Further Questions, and Doing More!

First of all a big thank you to "Usbport" on the CR4 engineering forum for pointing out the wikipedia graph that my graph is based on. This was the first step to getting the whole thing taken seriously.  I have been looking into how much direct sunlight comes from north of the east west line and there  is stuff to clarify.    First of all the degrees of sunlight and the amount of daylight/nighttime hours does not tally.  Also, if you look at the sollumis screenshots, they have "rays" of sunlight.  I presumed they are 20 minutes of sun travel but they might just as easily be 5 degrees of sun travel and they are bunched closer in the morning and evening than at midday.  I am pretty sure that the sun does appear to be going faster at midday and slower in the evening.  I could easily check this if I had not destroyed my model   This really matters because we need a decent idea of how much light we are gaining.
Finally a shout out for art of illusion.   It is a free  cross platform modeling software that is easy to learn.   I firmly believe that this is the best hope to personalize the greenhouse design.  The only extra thing that is needed  is a Sun engine Scene file.   Scene files are downloadable and anyone can make one. (I am crap at it but even I have made a scene file). if you want to talk to the guy who made art of illusion.  Here is how it would work. You import or copy  your elevation, plan and endview  into art of illusion, add the scene file. input the date and run it. It will show the light and shadows from any angle for your entire site for that day!  Any decent physics or computer guy could do the scene file, it would look great on your resume and it would be used all over the world for greenhouse, and garden design.



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    20 Discussions

    I made a video based on what I learned.  It has some of the same information but is arranged much differently and you might get a different perspective if you watch it.  (In the video I goofed and put in the wrong latitude for Victoria, but other than that I am pleased with it).
    The thing that really surprised me is just how far north and south the sunrise and sunset times and places move through the seasons. (When you plot them all together on a site plan) It is DRAMATIC!  Video is at

    As an odd side note - buying cheap showers and their doors can be a great source of large glass sheets that are well toughened, on a project I'm building they've come in very handy, had some sitting in storage for no apparent reason...

    5 replies

    Reply 6 years ago on Introduction

    I bet the shower door glass that you cant see through, the like, textured glass would be excellent because of the way it would refract the lighting coming in. great idea!


    Reply 6 years ago on Introduction

    Hmm might well do, I know that old school watery looking glass is great for refracting, since all the light gets through - used to have it through out the house and had to replace a window with normal for a bit and there was a big drop in light getting "around" the room...


    Reply 6 years ago on Introduction

    I actually didn't want to use the shower door because it is a bit large but it works fine. You are probably right about the texture too.

    I used some sort of slider shower door on this one too!
    Just added the pictures last night. They got me stalled and tempted me into making sliding doors because they have rollers. Couldn't do it with my material but had hinges so swing door it is! Hard to attach them (not much spare metal on the things to drill into) and latch them but I think it is figured out.
    Added pics of watering in clay pots too.


    6 years ago on Introduction

    In your search for more more more sun you may want to consider that in the height of summer when sun is coming from the north in the mornings and evenings, that its the time when greenhouse temperatures get very high and shading is necessary to prevent damage with a traditional lean to, so you are just giving yourself more work with no benefit. Also in the winter when the angle of the sun is lower you are reducing the light because of the angle of the glass and positioning of glazing bars.

    1 reply

    Reply 6 years ago on Introduction

    Nope, the higher front gets more sun in winter. There is absolutely nothing wrong with getting north eastern light in the morning when the greenhouse is cool anyway. Light is what plants live on. Also, the angles work better to bounce the light away around midday in summer than a lean to.

    I did a preliminary experiment that suggests that LESS THAN 12 hours per day of the sunlight in summer comes from SOUTH of the east west line. Could anyone verify that? If it is correct, it means that the lean away greenhouse is more useful than I thought.
    Thanks Brian

    3 replies

    Reply 6 years ago on Introduction

    Lets move to the equator.
    Then the sun is north of the East-West line, the equator, all the time for 6 months out of the year.
    Ok, that's an extreme example but it illustrates the seasonal declination motion.
    The further away from the equator you go the less extreme.
    So, the answer is yes it's possible depending on location and time of the year.



    Reply 6 years ago on Introduction

    Hi, Redrok, (Duane) have you any suggestions for controlling the "clock speed" for my "dripper tracker". I need something that goes something like 20 inches at a constant speed, It could be some sort of worm gear. It doesn't need to be strong. Just powerful enough to hold up a 1.4 inch diameter plastic tube.
    The best one (potentially most accurate) is called the liquid piston tracker but it is just a concept so far. Interesting that you commented today, because I was listening to talkshoe this morning. (The energy dude interviewed you)
    Another thing where your input would be valuable is solar powered DC bubble pumps. I am using a 120 volt bubble pump to irrigate my "pallet garden" and honestly it is working really well. It would be so much neater if it was 12 volt solar. But I cannot find a 12 volt bubble pump on the market.


    Reply 6 years ago on Introduction

    Hi, Redrok, I was kind of talking to people in northern temperate regions at the time! I used to go on the CR4 engineering forum where about one in 10 people are open minded and helpful and the rest were a mob shouting people down. Anyway, I asked that question there and the mob appeared first and lynched me! Then someone checked and anyway, it has been verified for northern temperate regions. It is always less than 12 hours in the southern part of the sky for me at 48 degrees north. In high summer, it is about 10.5 hours for me in the southern part of the sky. So for a while, I had people rudely telling me to get a compass. I would have guessed it was exactly 12 or more than 12 hours in the southern part in high summer. It was a big surprise to be less than 11 (At my latitude). Guess that makes your solar trackers more important, doesn't it?

    found a good demo of the sun's path in the sky. It is video at

    Just a note that Usbport on the Cr4 engineering forum came up good yet again!
    He has used the "starry night" program to confirm that the sun spends less than 12 hours per day in the south sector of the sky. Who would have thought! Here is most of his post from Cr4
    "On this date, at 53 degrees North (for Nottingham), the Sun rises at 4:48 AM at a point of 50 degrees azimuth. It reaches the due East position, 90 deg azimuth, at 8:23 AM. It transits the meridian at a civil time of 1:08 PM (the time on your wall clock).

    It then reaches the due West point (270 deg azimuth) at 5:52 PM, and then sets at an azimuth point of 310 degrees at 9:25 PM. Total daylight hours is 16 hours, 37 minutes. The Sun spends 10 hours and 37 minutes in the 'South' part of the sky, between 90 and 270 degrees azimuth. It spends 3 hours and 33 minutes in the Northeast part of the sky and 3 hours and 35 minutes in the Northwest part of the sky."
    He also included diagrams from the program.
    Thanks Usbport!!! You made the difference.


    6 years ago on Introduction

              "..why I did it and why it works good."
    Should be:
              "..why I did it and why it works well."

    I'm sorry to be a grammar snob...
    Greenhouses are awesome, and it's great that you were able to build one, especially with free glass!  Great job : )

    2 replies

    Reply 6 years ago on Introduction

    No, its fine. I am from an old country and I was trying to write American to "blend in". I will correct it now.


    Reply 6 years ago on Introduction

    Well, today here in America, if you want to write American then you did just American (English) is a dying art now. Especially on the Internet. I know because My With has her Masters Degree in english and creative writing and works as a full time professional proof reader so i have to hear it all the time. Do you know what emailing her is like? or worse... texting her? lol,lol,lol...

    Anw way, dont worry about a thing. Write how you want to, we'll figure it out or die trying.

    I do like your greenhouse, We want to build a green house as well but the town we live in would never let us make one like this because they have really strict building codes. if I wanted to even build a ground level deck, I'd need all these permits and inspections.. when all is said and done, it would cost me a couple hundred dollars just to be able to build it, never mind the actuall building I could throw up a 16x12 deck in a few hours once the concrete footings have cured.