Tag Archives: prevailing winds

Where is the best place to put a greenhouse?

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Considerations for determining optimum location for growing, air flow, snow shedding and ground moisture

The first bit of advice we share when asked that question is “Do not put a greenhouse in a place that is not good for anything else”.

You need to pick the best spot to accomplish the goals for your greenhouse. Any of the reasons why this spot would be less than desirable, will come back to haunt you.

This is particularly true when it comes to ground water. If a particular piece of land is always moist or has a very high water table, moisture will be an ongoing problem. A greenhouse will trap and exaggerate excess moisture and become a very unhealthy spot for plants.

If the soil is sub-standard or undesirable where you put the greenhouse, you will be putting extra effort into bringing the soil up to standard.

Proper consideration needs to given to shading on the property. Plants grow in direct proportion to the amount of daily light they receive. Really analyze where and when shade happens. Vegetables and flowers need sun.

A greenhouse needs to be level from side to side so shed snow uniformly. With uneven snow load on a building, it will surprise you how little snow can be a problem. 

Excavation to level a site is usually expensive and messes with the make up of the soil. There are ways to build up the low side if that becomes necessary for the location of your choice.  Some end to end slope is not a problem structurally.

It is generally acknowledged that a north/south orientation will pick up the sunlight better but this is not a serious consideration unless you are into production crops.

If your prevailing winds are constantly hitting the side of the structure, there will be a sideways push which is good to avoid. This orientation will also encourage uneven snow loading. Ventilation is typically easier if the prevailing wind hits the end of the building.

Since the chances of having the “perfect” location, is not likely, it is important to evaluate all of the angles.  Some of the undesirable points can be worked around better than others.

By doing a thorough assessment and then prioritizing, you will be able to come up with the closest to perfect that is practical. You will also have an idea beforehand on what needs to be done sooner than later.

Here is to happy planning and planting.

Winter Care and Maintenance

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These buildings are not industrial grade shelters and, as such, some caution must be exercised under some winter storm conditions….

Please see the WINTER CARE page in our installation guide for additional information. We also have a Winter Care FAQ page with articles we have posted on this topic

BEWARE of this sequence which creates a “worst case scenario”:

Freezing rain, followed by dropping temperatures, Lots of snow followed by rainfall. It is easy to triple the weight of the snow load in 30 minutes.

Our structures are designed in a gothic shape with a slippery cover to be lightweight and snow resistant. This encourages the snow to slide off quickly.
This is not an industrial high snow load building. We do our best to always point out applications where the capacity of the structure is being compromised. Extra hoops or thicker steel are an economical way to increase wind and snow load capacity. We take pride in the sturdy shelters we manufacture and supply, but must point out that we cannot warranty against weather conditions

Snow removal, when occasionally required, is a simple task. Uneven snow loading is deceiving, since the total weight is not a problem but the lateral force can cause the hoops to distort.It is rare to have any significant snow build up on the roofs; however,

DO NOT GO INSIDE A BUILDING WHERE THERE HAS BEEN OBVIOUS STRESS!
Be aware of these scenarios where excessive snow build up is possible and damage could follow:
A wet snowfall followed by dropping temperatures
A building 90° to the prevailing wind (drifts could form on the backside of the building)
A building attached to and situated downwind of a taller building (significant drifting)

A building 90° to another building that has a higher roof, could cause a surge in snow weight when the snow on the upper roof slides off.

Preventative measures for excessive snow build up (where possible):

Build structures inline with the prevailing wind
Build structures level from side to side to create uniform shedding
Do not attach your building to a larger existing building

Install a heat source to melt the snow

Economical additions to increase your structure’s snow resistance:

Install cable or tubular cross-ties at each pair of hoops, to create a triangle (when using cables there is no need to put them under tension)
Place wooden or metal support posts under the ridge. These can be suspended from the ridge with no more than ½” ground clearance. This will provide support as soon as there is load and structure movement will not dislodge your supports.

Use closer hoop spacing for the first 12’ section away from another bigger building

Pointers for removing snow:

NEVER remove all the snow from one side and then the other
Remove the snow off the top of your building before using a machine (snow blower, etc) along the sides

Use a padded piece of 1×4 wood on a pole (create a “T” shape) as the best tool for gently bumping the inside of the cover

BEWARE of this sequence which creates a “worst case scenario”:

Freezing rain, followed by dropping temperatures, Lots of snow followed by rainfall. It is easy to triple the weight of the snow load in 30 minutes.

Please call us if you have any questions about any of this. Thank you

Properly Venting a Building

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Properly venting a building is a critical consideration when planning your building.

Getting rid of the initial ground moisture, quickly, when you have erected your new shelter is something many people do not think of. Quality air changes for plants or animals is something that automatically comes to mind. Getting rid of moisture is equally as important for storing your valuables.

Vent4Since warm air holds moisture and warm air rises, it is important to have venting capacity as high as is possible.

Venting through the roof, with individual turbines or a continuous roof vent, is the most effective but also the most costly.

This is only really necessary when you are in a very protected spot and there is a real need to keep the temperature down in a long building.

vent3Most medium length buildings that have the ends facing into the prevailing winds, can be adequately vented with gable end peak vents.

  • Make sure that these openings are as big as possible and as high as possible.
  • It is also important to make sure your “windows” can withstand the winds in your area.

Our centre pivoting gable vent has filled this requirement very effectively.

  • With part of the window going in and part of it going out, the wind can never get hold of it.
  • With the top and bottom rope through a double pully on the ridge, it is easy to maintain precise control over the opening area

As with all the other considerations, please do not hesitate to contact us with your specific set of circumstances and challenges

 

Greenhouses 101: Orientation and Location

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The location and orientation of a structure are two different things that need to be given careful thought to since the consequences are so long lasting. The cost of making changes after the fact are significant and often make it impossible. You should never put a structure somewhere simply because the area is not good for anything else. Location is more about what you need and orientation has to do with what the structure needs to perform well.

Location has to do with accessibility to power, water and handling the product that the structure shelters. If bringing in water, electricity or a driveway is too costly for the budget at present, you will have to start weighing cost versus benefit. This can only be accurately done if you understand the requirements, choices and consequences. Drainage, ventilation and light requirements are also important considerations which change from location to location.

Orientation has to do with a structure being north/south, east/west, or somewhere in between. This will have an impact on ventilation, light, snow shedding and lay of the land. For all of these things you need to have a good handle on what the structure needs to perform well. A structure must be level from side to side to shed snow well but can have some slope from end to end. Ventilation is easier when a structure is inline with the prevailing winds but you do get more sunshine in the building if it is north/south.

Check out the presentation video and the rest of the series Norm spoke on Greenhouses 101 here. Stay tuned for the end of  January 2016 when he presents Greenhouses 202!