Hoop House & High Tunnel Greenhouse Calculator

Controlled Environment Agriculture (CEA): High Tunnels & Season Extension

High tunnels (unheated hoop houses) protect high-value vegetable crops from harsh frost, excessive rainfall, and wind, extending the growing season by 4 to 8+ weeks in spring and autumn.

Quonset vs. Gothic Arch Profiles

• Quonset (Semi-Circular): Easier to bend, highly aerodynamic in wind, but flat tops can accumulate dangerous snow loads in northern climates.

• Gothic Arch (Pointed Ridge Peak): Sheds heavy snow and shedding condensation drips down the walls rather than dropping onto plant foliage.

How to Use This Calculator

Enter your Tunnel Width (Feet) (e.g. 20 (14, 20, or 30 ft standard)), Tunnel Length (Feet) (e.g. 48 (48, 72, 96, or 100 ft)), Straight Sidewall Height (Feet) — choose from 0 ft (Low Quonset / Direct ground arch), 4 ft (Standard High Tunnel with roll-up sides), 5 ft (Commercial High Sidewall), Hoop Arch Profile Style — choose from Gothic Arch (Pointed peak -- superior snow/rain shedding), Quonset (Semi-circular rounded arch), and Hoop / Bow Spacing (Feet) — choose from 4 ft Spacing (Standard -- supports moderate snow & wind), 5 ft Spacing (Lightweight / economical), 3 ft Spacing (Heavy snow load zone). Results update instantly as you type — adjust any value to compare scenarios.

The Formula

High tunnel hoop house and greenhouse geometry formulas: Hoops / Bows = (Tunnel Length) / (Hoop Spacing) + 1 Bow Arc Length = (π × r) + (2 × h_sidewall), r = (Width) / (2) Arch Peak Height = h_sidewall + (1.25 × r) Poly Plastic Film Width = Bow Pipe Length + 6.0 ft (side burial/roll-up allowance) Film Length = Tunnel Length + 10.0 ft (end-wall wrapping allowance)

Worked Example

For example, building a 20 ft wide × 48 ft long Gothic arch high tunnel with 4 ft straight sidewalls and 4 ft hoop spacing: Requires and 26 ground anchor posts. Each bow requires 38.5 ft of galvanized pipe, creating a center peak height of 16.5 ft. The greenhouse poly plastic film roll must measure at least 45 ft Wide × 58 ft Long.

Understanding Your Result

Housing affordability benchmarks: keep total housing costs (rent or mortgage + utilities + insurance) below 30% of gross income. The "28/36 rule" for mortgages: housing costs ≤28% and total debt ≤36% of gross monthly income. In high-cost metros (NYC, SF, LA), many residents spend 35–50% of income on housing — financial planners recommend aggressive savings to compensate when above 30%. Every 100/month increase in housing cost reduces your sustainable savings rate by approximately 2% of average US income.