If you’re planning on buying a greenhouse, it seems like common sense to start with the frame but there are other factors that commercial operators should consider before choosing a frame style.
1. Clarify Property Ownership
Is it owned, leased or borrowed? If it’s owned, the sky’s the limit. If leased or borrowed, you might need something less permanent in case you need to tear down and rebuild without causing a financial crisis.
2. Understand Your Property Zoning
Next on the list is zoning and the location of the property. Residential properties can be a bit of a challenge due to the permitting laws in these zones. The counties will look at the size of the structure, coverings you choose, concrete and offsets. When considering permitting, pay attention to your wording. A “high tunnel” is considered temporary and is easier to apply for a permit, whereas a “greenhouse” is permanent.
Greenhouse manufacturers also require a permit. If a neighbor isn’t pleased with your new structure and they call the building department, it’s best to know all the information on building specs and adhere to the code. Commercial and industrial zoning can be somewhat easier since it’s usually out of residential areas. Some areas have dual zoning and can cause even more red tape in the long run. Some structures are exempt from permitting. So, before rushing into purchasing your frame, be clear on your property’s zoning.
3. Pick the Greenhouse to Get the Permit
Once you’ve talked to the building department and have gotten some feedback and a verbal OK, it is time to start picking out the greenhouse. The greenhouse will need to meet the building codes for wind, rain and snow ratings for agricultural structures in your zone and property. That will narrow down the choices if you’re in a high wind or snow zone.
After consulting with your greenhouse expert, you should be able to go forward with the engineering process. Most operations in commercial/industrial zones need engineered plans for permit approval. This is an official set of drawings that carry an engineer’s stamp on the bottom of the front page, which puts all the responsibility on the engineer that the building will meet the required code for that project. If the county needs a revision, it goes to the engineer. If there is a failure or discrepancy on the actual structural portion of the plans, the engineer is the go-to person. This does not always grant you a permit.
It’s only after the permits are approved that you should actually put money down on a structure. In the meantime, the county will tell you what’s needed for site preparation, erosion control, water catchment or diversion, etc. Some areas require more infrastructure than others. It’s always best to work with a project manager from the area. They typically know the proper terminology and are prepared for curve balls in the permitting process.
4. Get the Greenhouse!
Now that we’ve conquered the permit, let’s order this greenhouse! A qualified greenhouse company with a background in agriculture can help you find the best style for your region, property and weather. Most hoop houses, high tunnels and gothic frames can be ready to ship in 1-3 weeks, depending on size and accessories. Larger commercial structures can take 6-8 weeks before the first truck can roll out. This is usually what we call gutter-connect structures.
Greenhouses seen on farms and in nursery supply centers are commonly single structures. This means there is one greenhouse with no other connecting structures This freestanding structure might have guttered connects, or it might not. Some greenhouse models automatically come with gutters, while others just let the water fall to the ground. The greenhouses that do have a gutter often times can be gutter connected. This means we actually put another greenhouse directly next to another and join them at the gutter.
Various Construction Factors
A greenhouse is typically made up of four sides (two end walls where you normally see doors, and two side walls) and a roof. The side wall height can also be called the gutter height and eave height. Back to the gutter-connected, this type of greenhouse allows for acreage-size structures. It’s also called a range of greenhouses. For example, you might have a range of 11 42-ft. by 120-ft., gutter-connected structures and in that range, six are flowering, three are veg and the other two are processing. The processing can be clad in sheet metal like a warehouse while still gutter-connected to the flower and veg range of houses.
Grading, piping, gravel, concrete and electrical preparation all help you get ready for the greenhouse. Concrete slabs are not a structural component of the greenhouse but are a nice addition. A slab can be floated in after the columns/stubs are set around the perimeter. Most people will use crushed gravel. Road base material can be watered and smoothed almost to as nice a surface as concrete for less than half the cost. Another thing to keep in mind is floor heating. You’ll save yourself in overhead with root-zone heating. Remember that 30% to 35% of the heat from air-fired heaters actually reaches the plants. Floor or bench heating will make 95% of that heat concentrated to the plant. It makes a huge difference in quality and yield stability.