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Greenhouse Thoughts Part II

April 21, 2012

Bringing a greenhouse into your life is a commitment for sure. One caveat, though, if you don’t want to garden a lot or for a good portion of the year, think twice.  A greenhouse, even a cool one needs attention.  They cool down fast at sundown and heat up even faster when there is a break in the clouds.

Ours has served as a classroom, my daughter learned to read by deciphering seed packets.  She also learned the value of garden work too, there are many chores in a greenhouse that can be handled by small children. Besides chores, valuable life lessons can be taught.  Observing your food from seed to table comes to mind.

While we choose to not “grow” vegetables in the winter that require protection, winter harvesting is a compelling reason to have a greenhouse.  Any of Eliot Coleman’s writings can lead you in that endeavor.

However, our chickens enjoy their small greenhouse during the winter.

And they get their start in a small greenhouse too.

Styles vary, commonly you see semi-gable like our large greenhouse or quonset and semi-quonset like our smaller brooder greenhouses.  Both have pros and cons.  We have found the semi-quonset to be stronger in snow storms than the semi-gable.  However, you can order or make trusses to strengthen the semi-gable structure.  A good place to peruse styles is the FarmTek catalog, you can familiarize yourself with the terminology and get an idea of what is available, but I would recommend buying from a local company if you can.

Basically you determine the width you want, and you can customize the length by buying more bows.  One of the determining factors in this part of the design is the plastic width and length.   Our 30 x 72′ greenhouse uses one roll of 48′ x 100′ roll of Tufflite IV, this covers the entire top and sides and leaves enough for endwalls.

Site consideration is very important for several reasons.  Questions to ask yourself when you’re picking your potential greenhouse site:

♥  Are there any trees that will cast shade on your greenhouse?  Winter time is a good time for this exercise when the sun is the lowest in the sky.

♥  Is there easy access with a vehicle, so you can deliver supplies, and remove your harvest easily?

♥  What do you want to grow, tall crops, short crops?  And when, summer, winter or both?

♥  Do you want to use part of your hoophouse for tool/equipment storage or only for growing?

♥  Visit growers in your immediate area and pick their brains, do they like how their greenhouses function, what would they do differently?  What are their biggest weather concerns…heat, wind, snow, flooding, hail?

♥  Orientation?  Winter crops will do better with an east/west orientation since that will give you a little more heat in the winter, north/south will give you more light to all your crops during the growing season.  Even with an east/west orientation in cold winter areas you will still need additional heat and/or additional covers for plant protection.

Our greenhouses are oriented north and south for maximum light to all the crops during the growing season.  Our gardens are the laid out the same.  This is where you get all sorts of opinions and reasons for east/west orienting versus north/south.  Remember this is a blog post about our farm and our experiences which may be different from what you know or think or have seen in practice.   It’s now recommended by the USDUH that any hoophouse constructed north of the 40° parallel be constructed on an east/west axis.  I will disagree (we are at the 45 parallel) for several reasons.  You can gain a little more light through the sidewall than through the roof if you are oriented east/west, but that is more of a winter consideration and fails to be even noticeable in the summer.  I would say if you’re wanting to grow in winter and need to retain heat, east/west axis is more important, however be prepared for that greenhouse to be too hot during the summer without adequate ventilation.  Length plays a part on that too, any hoophouse longer than 48 feet without much sidewall or end wall ventilation may get too hot for most crops, especially if it is oriented east/west.  Roll-up sides and adequate vents can help with that.  I know growers with houses oriented both ways, and the east/west folks are mostly concerned with winter growing for their hoophouses, but they orient all their summer outside vegetable rows north/south.  A neighbor who has an east/west hoophouse for personal use is now wishing she had built hers the other way.  She grows tomatoes and peppers mostly in her hoophouse and now realizes that she is committed to always having her tomatoes on the back side, since she discovered the second year in her rotation that if she planted her tomatoes on the south side of her greenhouse, they shaded all the other plants by August and severely diminished her harvest on all plants shaded by the tomatoes.

For us, the north/south axis works great, even though we may be sacrificing a little winter heat.  The south end wall provides enough shade I can still start plants in the greenhouse during the summer as the seeding bench on the north wall gets too hot by June.  Likewise, the hot north end in summer becomes the warm north end in winter and is perfect for my over-wintering greens.  Just like any garden,  seek out the different micro-climates.

Other things I consider important in our greenhouse.  They may or may not apply in your situation.

♣  No formed beds – this means it’s pretty easy to add amendments and work the soil.  Even if you don’t have a tractor, you don’t need to commit yourself to a lifetime of amending your soil with a wheelbarrow.  You can hire someone to till for you and haul in your compost at the beginning of the season.  No fixed beds keeps your options open.

♣  Wide sliding doors for easy access.  Hinged doors are heavy and are always in the way and hard to open, soil and debris build up over time making a swinging door hard to use.  When designing your doors, think of how you are going to use it, at least wheelbarrow width plus for a minimum.

♣  High side-walls so I can work the soil with equipment.  The taller roof also helps with ventilation.  Lower styles are nice  too, but they do get wicked hot for plants, and the workers.  We used our greenhouses for winter laying hen housing, and cleaning out the deep bedding was much easier with taller side-walls.

♣  Roll-up sides for cross ventilation.  Not necessary, but it’s really a nice feature.

To conclude, these items were/are important to us when deciding the what, where, and how of siting our greenhouses.  You may have more factors to take into consideration for your own project, but hopefully this is good food for thought.

13 Comments leave one →
  1. April 21, 2012 2:56 pm

    Wow, food for thought, indeed! Thanks for putting so much time and effort into sharing your experience!

  2. April 21, 2012 5:17 pm

    Great posts, thanks for all the info! We’ve built a small 8 X 16 to get us started, but would love to upgrade in the near future.

  3. April 21, 2012 5:49 pm

    I hear ya on the wicked hot short greenhouses. Mine is a quonset style I use mainly for propagation and it gets really hot if its still and the sun is out, even with the roll ups up. Luckily (for the greenhouse) we don’t get many still days in the summer.

    • April 22, 2012 6:19 pm

      Went to a conference last week and heard John from Gathering Together talk about ‘mudding’ their tunnels in the summer once the fruit sets, helps keep the peppers and other crops from sun burn and keeps the extreme heat out. I think i may try it this year.

      • April 24, 2012 5:44 am

        Ben, it works pretty good, I used that technique when I grew my peppers in my semi-qounset, because the low tunnels heat up so much. I’m just hoping for a nice enough summer that we need to do that 😉

  4. April 22, 2012 3:15 am

    Our greenhouse is North/South but that was a topographical decision on our undulating plot and not wanting to site it in plain view of the whole world. Thought you might be interested in how our greenhouse is constructed.

    This was our first polytunnel
    and the skeleton is here
    This made good use of the space and was certainly easy to get in and out of. Unfortunately it didn’t last a winter for two reasons. One we were away when the snows came and away for a month in the heaviest snowfall for a long time, even here in Latvia, it was a metre of snow and ice. Two it may have survived if the foundations had been completely square (not our fault honest) and cross pieces had been added.

    This is our new greenhouse
    Interior view as you see we have a lot more internal structure to cope with the snow. It is not as roomy as the first, but we still stored a trailer in it over winter and it survived another snowy winter – not as bad as the last one and we were around to clear off the snow. The fleece is for shading as it lets UV through which hubby found out the hard way.

    exterior view

    Both frames were constructed by locals with local wood, but then again Latvia is 50% forest. We wouldn’t be without our greenhouse, it has been perfect for our needs.

  5. Tammy permalink
    April 22, 2012 3:26 am

    I just built a small tunnel for my garden this spring. I look forward to the jump start it will give my seeds this spring and the extension for the fall. I’m babystepping my way into a greenhouse! Thanks for the great info.!

  6. April 22, 2012 4:40 am

    Thanks much for these helpful posts. I built a small 9×16 homemade hoophouse 4 years ago, and we have decided we’ll replace it with something larger when the plastic goes on this one, and use this frame for a winter run for our hens. This is good information for us as we think about what style greenhouse to purchase. Like you, I use mine for season extension and overwintering greens, rather than year round growing, and will no doubt stick with that scheme as I work away from home during the winter months.

  7. April 22, 2012 12:55 pm

    Especially love the photos this time – I’ll bet that one of your daughter is a real fave : )

  8. April 23, 2012 8:15 am

    Well looks like dumb luck worked out for us so far….. And as I had feared/hoped ventilation to shed heat is going to be our biggest problem, but I am hoping to do more winter growing in our hoop house….

    • April 24, 2012 5:46 am

      adalyn, no matter too hot or not, you’re going to love the covered space for gardening. Any way we can get some heat in the summer here for gardening is a bonus, plus the winter gardening space. You’re going to be in seventh heaven 🙂

  9. jleejj permalink
    April 29, 2012 1:42 pm

    I appreciate this two part series on greenhouses. It’s given me a lot to think about. A greenhouse is the next big step for us in the garden, mainly so we can reduce how many plant starts we buy and to get a jump on the tomato season.

    What are your thoughts about permanent greenhouses vs. hoop houses? We have a lot of old windows accumulating from the house remodel, so we have been considering a small permanent greenhouse built from recycled windows and a translucent roof.

    • April 29, 2012 2:31 pm

      Jleejj, I think building a usable structure from what you have would be great. Anything that enables a gardener to expand their horizons is a win-win. You can always do a hoophouse later, if you want to. 🙂

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