BRINGINGSCIENCE

Cooperative Extension Service • Circular 606TO YOUR

LIFE

COLLEGE OFAGRICULTURE ANDHOME ECONOMICS

Hoop HouseConstruction for New Mexico: 12-ft. x 40-ft. Hoop House

Cooperative Extension Service • Circular 606 1

HOOP HOUSEThe hoop house, cold frame and high tunnelcan be basically the same structure withminor changes to the design. The hoophouse gets its name from its shape, althoughhouses can be constructed with straight linesusing elbows to get the desired shape for abuilding. The shape of a hoop house causeswater and snow to be shed from its exteriorwhile permitting sunrays to provide heat.

Houses of this category are made withaluminum pipes or plastic PVC pipes ashoops that are covered with a single layer ofpolymer plastic covering. A second layermay be added for better insulation.

REASONS TO BUILD A HOOP HOUSEHoop houses are ecosystems all in themselves,and the environment inside can bemanipulated to a crop’s need.

Hoop houses can extend the growingseason, since you may plant early, thecollection of heat units with the plant ishigher resulting in earlier harvesting. Plantingin late summer and early fall allows you toproduce and harvest into the winter months.

Planting in a protected environmentguards the crop from Mother Nature’swhims and control the crop’s quality.

Using the hoop house for seasonextension increases income over a longerperiod of the year and allows the use ofdifferent marketing strategies.

FACTORS TO CONSIDER BEFOREBUILDING A HOOP HOUSEHoop houses are relatively inexpensive toconstruct, costing around $1 per square foot,with low maintenance once constructed. Theyare easy to build and adapt to small land unitsto meet the needs of gardeners and farmers.

Since plants need sunlight to grow, lightpenetration should be a concern in structuredesign. Grow lights can be used but requirean electrical source. In an area where windand snow are part of nature, consider theload limitations the structure must have toendure stress.

The height of the hoop house can beadjusted so that one can walk and work insidecomfortably, therefore, one must think aboutheight before construction starts.

SELECTING A SITEFOR A HOOP HOUSESelect a site that is moderately level withgood drainage and good soil for planting. Asite can be modified by soil fill so thatconstruction is on a pad. Select a site in anopen area where trees and other obstacles willnot affect sun penetration.

Consider the surrounding area so thestructure will be protected against highwinds and heavy snows, thus providinglonger life. Water and electricity may beneeded for the hoop house, so a sourcenearby should be considered.

Hoop House Construction forNew Mexico: 12-ft. x 40-ft. Hoop HouseDel Jimenez, Ron Walser, Reynaldo Torres1

1 Agriculture Specialist, Rural Agricultural Improvement and Public Affairs Project (RAIPAP), Fruit Specialist, RAIPAP, and Agriculture Agent, Taos CountyExtension Service, respectively, New Mexico State University, Las Cruces, New Mexico.

Cooperative Extension Service • Circular 6062

Security and protection against vandalismof the hoop house and crop may also be afactor to consider when selecting a site.

ORIENTATION OF THE HOOP HOUSEPreferably, position the hoop house in anorth south direction. Air currents comefrom a south, southwest direction and willhelp ventilate the hot air buildup within thehoop house on hot days. The north southorientation also favors sun penetration, sincethe sun tracks from east to west going directlyover the hoop house for maximum lightpenetration.

LAYING OUT THE HOOP HOUSEBegin by choosing the size of a hoop housethat meets your needs. Then square off thecorners of the hoop house using thePythagorean Theorem.

A2 + B2 = C2

(Length of Building)2 + (Width of Building)2

= (Hypotenuse of Building)2

Example: A (12-ft.)2 + B (40-ft.)2 = C2

144-ft.2 + 1,600-ft.2 = 1,744-ft.2

√1,744 = 41.76-ft.C = 41.76-ft.

rebar 24-ins. long. Drive these stakes 12-ins.into the ground at a 30-degree angle fromvertical pointing inward. Half the stake willnow be underground and half the stake abovethe soil.

Place a string around the four corners tooutline the hoop house’s foundation.

Along both lengths of the hoop house andinside the string, drive 24-in. rebar stakesevery 4-ft. apart, 12-ins. deep, at a 30-degreeangle, until you reach the desired length.

SETTING THE PLASTIC PIPE HOOPSThe standard length for PVC pipe is 20-ft.With a 12-ft. wide hoop house, the heightin the center is approximately 6 1/2-ft.On a 16-ft. wide hoop house, the height isapproximately 5 1/2-ft. Adding extra lengthsof pipe will increase the height and width ofa hoop house. It is recommended that youadd the extra length to the ends of a 20-ft.pipe because, when the pipe is bent, thestress is not as severe on the glued joint.

There are various size PVC pipes thatcan be used for the hoops: 1-in, 1 1/4-ins.,1 1/2-ins., 2-ins. are the most common.The desired height, length and the localenvironmental conditions will determinewhat size is best.

We recommend the use of 2-in. PVC,because it holds up well to winds blowing50 mph and the occasional snow 8-ins. thickon the plastic. Use new plastic pipe forconstruction because weathered pipe will bebrittle and break when bending. Once thepipes for the hoops have been bent andweathered, the pipe will retain its bent shapeand can be reused for another hoop houseproject.

When the rebar stakes are set, it’s time toplace the PVC pipe. This is accomplished byplacing one end of the PVC pipe over one ofthe stakes, then bending the pipe by pullingon it; place the opposite end of the pipe onthe lateral stake on the opposite side. If therebar stakes are perpendicular to the ground,it is very difficult to place the pipe on the

Squaring the building is critical so thatthe rest of the structure proceeds normally inconstruction.

SETTING STAKESAfter squaring the corners of the hoop house,set four stakes in the ground using 1/2-in.

A(12-ft.)

B (40-ft.)

C (41-ft. 9-in.)

Cooperative Extension Service • Circular 606 3

spike. That is why stakes should be placed ata 30-degree angle (figs. 1-3).

PLACING THE WOODBASEBOARDSBaseboards are installed to give the hoophouse stability, and are where the plasticcovering is attached. On the outside of thehoops along the base of the hoop house,place the baseboard using 2-in. drywallscrews fastened to the 2-in. PVC pipes.

The baseboards should be 1-in. x 4-ins.x 10-ft. long boards, butted and fastenedtogether by short brace pieces. You may alsouse 2 x 4s. Make sure the screws and bracepieces are faced toward the inside wheninstalling the baseboard.

When both sides are in place, drive two24-in. rebar stakes bent in a “J” design, 10ft. from each end along each side (figs. 4-5).These are hooked over the baseboard. Thiswill help keep the hoop house anchoredduring high velocity windstorms.

INSTALLING TUBULAR BRACESThere are three (3) tubular braces runningthe length of the inside of the hoop housethat will be used for stability and also forirrigation. The tubular braces will be madefrom 3/4-in. PVC pipe. PVC pipe comes in10 or 20-ft. lengths. Mark the 2-in. pipeswhere the tubular braces will be attached.The mark will be 72-ins. from the end of thepipe, and also down the middle of the pipe.Marking the two end hoops and running astring can easily achieve this.

Glue the 3/4-in. PVC pipe together andmark every 48-ins. This marking willcorrespond with the distance between eachof the 2-in. hoops.

Start attaching the tubular braces fromthe front of the hoop house. Make sure thebrace is flush with the outside of the firsthoop, and that the markings should coincidewith each other. If you are not using the

tubular braces for irrigating, you can attachthe tubular brace directly to the 2-in. pipeusing a 2-in. drywall screw. If you will usethe tubular brace for watering, you must usea 3/4-in. one-hole or two-hole conduit strapto attach the pipe (figs. 6-8).

ATTACHING POLYETHYLENEPLASTIC COVERINGThe greenhouse plastic acts as the skin to thestructure, letting light rays in and keeping theweather out. There are different grades of polycovering, but a 6-ml. weight works well forhoop houses. It is recommended to usepolyethylene coverings that have been treatedwith a UV inhibitor, and guaranteed to last atleast three years. Unprotected polyethyleneplastics will break down over a growing season.

Greenhouse plastic coverings come inrolls 100-ft. in length and in widths rangingfrom 12-ft. to 48-ft. The length of the pipethat makes the hoop determines the width ofthe plastic covering, and it is recommendedto add at least a foot on each side of thehouse width.

To successfully apply the plasticcovering, take the following steps: have extralabor available; make sure there’s no wind;work in the afternoon, when the plastic canheat up and stretch. Lay out the greenhouseplastic in a clean work area alongside of thehoop house, so you can measure and cut theplastic to the size required. Using a straightedge, cut the plastic at least 4-ft. longer thanthe building. This way, you overlap each sidewith 2-ft. of plastic. After the plastic is cut,find the edge of the cut piece of poly andcenter it over the hoops by dragging gentlyacross the top. Let the plastic rest on thehoops for 15 minutes to absorb the heat.Keeping the plastic stretched, attach one sideby sandwiching the plastic poly coveringbetween a 1-in. x 2-in. x 8-ft. long furringstrip onto the baseboard, driving 2-in.drywall screws every 2-ft. (By using screws inthe baseboard, it is easy to take out to replace

Cooperative Extension Service • Circular 6064

plastic covering.) When one side is complete,attach the opposite side in the same manner.When complete, shovel dirt onto the extraplastic at the base of the hoop house.

On the ends, stretch the plastic tight andsandwich the plastic poly covering between1-in. aluminum stripping and the 2-in.plastic hoop using 1-in. drywall screws everyfoot apart to attach (figs. 9-12).

ADDING END WALLSEnd walls are used for access into the hoophouse, protection against the elements ofnature and also to permit air circulation andremove heat.

Stretch a string at the bottom of the firsthoop, and find the center, which will be usedas a guide to construct the entrance. Fromthe center point, measure along the string 2-ft. in each direction. Mark these spots anddig a hole 6-ins. round and 1-ft. deep. Placea 2-in. x 4-in. x 8-ft. board into each hole,and angle the top so that the wood fits underthe hoop. Level the 2 x 4 in both directions,making sure there are 48-ins. from the centerof the wood. Fill in holes with dirt, andsecure the top with a 3-in. drywall screwrunning through the pipe into the wood.

When the uprights are set, place the firstpiece of plywood (4-ft. x 8-ft. x 1/2-in.) upagainst the middle. This will be the door.Trim the door to fit the shape of the hoop.After the door is in place, continue placingplywood on either side of the door, screwingthese pieces into the uprights and 2-in.PVC pipe until the wall is complete. Fastenthe door to the uprights and plywood usingtwo hinges as well as a latch for securing thedoor. The finished side should reflect theshape of the hoop house.

This wall can be repeated for the oppositeside of the hoop house if you wish to have anentrance on both sides (figs. 13-15).

ADDING THE BACK WALLThe back wall provides protection against theelements and also permits air circulation toremove heat. On the backside of the hoophouse make a frame out of 2 x 4s that willcover the bottom half of the hoop house.Make sure that you have upright poles thatgo into the soil 12-ins. This gives thestructure stability. Cover the frame with1/2-in. plywood, and screw the plywood intothe frame and 2-in. hoops.

The upper portion of the back wall will alsobe covered with plywood but will hinge down topermit air circulation. The hinges attach to thebottom half of the frame (figs. 16 and 17).

ADDING ROPESRopes are used to help secure the polyethylenecovering in place when gusts of wind blowthrough the hoop house. Polypropylene ropes1/4-in. in diameter can be looped over thehoop house every 10-ft. apart and tied tostakes in the ground for added protection.This will help add life to the covering.

CONCLUSIONA hoop house is a practical tool that isaffordable to construct, practical to use, canextend the growing season and possiblyimprove income for an operation (table 1).

By choosing selective low-profile fruits andvegetables that withstand cold temperatures, itis possible to grow most of the year withoutthe use of heating equipment and electricity.These structures, with special plastic covers,can keep inside temperatures 4º to 6º Fwarmer than outside temperatures, and witha row cover made from specially improvedwebbings over the crop, another 4º to 6º Fincrease can be obtained.

With these structures one can makefarming of food crops affordable, profitableand fun all year around.

Cooperative Extension Service • Circular 606 5

Table 1. Hoop House Construction Material List and Estimated Cost, 12-ft. x 40-ft.

Item Cost Quantity Total Cost

1. Plastic PVC Pipes $7.00 13 $91.002-in. x 20-ft.

2. Plastic PVC Pipe $1.25 8 $10.003/4-in. x 10-ft.

3. Rebar $1.50 22 $33.001/2-in. x 24-ins.

4. Glue 16-oz. $5.00 1 $5.005. Screws (Drywall Screws)

2 in box, 150 Screws $5.00 1 $5.003 in box, 150 Screws $5.00 1 $5.00

6. Wood Strips $3.00 8 $24.001-in. x 4-in. x 10-ft.

7. Plastic Cover (6-ml.) $200.00 1/2 $200.0022-ft. x 100-ft.

8. Plywood $24.00 6 $144.001/2-in. x 4-ft. x 8-ft.

9. Wood Studs $3.00 8 $24.002-in. x 4-in. x 8-ft.

10. Hinges $1.00 6 $6.0011. Latch $3.00 3 $9.0012. Aluminum Trim $1.00 12 $12.00

1/4-in. x 1-in. x 10-ft.Total Cost $568.00

Figure 1. Laying out the 2-in. x 20-ft. PVCpipes that will be used for the frame.

Figure 2. Bending the 2-in. x 20-ft. PVC pipeand setting them on 1/2-in. rebar stakes.

Figure 3. The hoop house structure takesshape.

Figure 4. Attaching the baseboards to thebottom of the PVC pipes.

Cooperative Extension Service • Circular 6066

Figure 5. Laying out the tubular 3/4-in. braces. Figure 6. Marking the height where the braces willbe attached.

Figure 7. Gluing 3/4-in. pipe together to be usedas braces.

Figure 8. Attaching the 3/4-in. PVC pipe braces tothe structure.

Figure 9. Rolling out the plastic to the appropriatelength.

Figure 10. Covering the hoop house with 6-ml.plastic film.

Cooperative Extension Service • Circular 606 7

Figure 11. Stretching the plastic overthe hoop house structure.

Figure 12. Attaching the plastic coverto the baseboards.

Figure 13. Marking the door to be cut. Figure 14. Attaching the front door tothe hoop house.

Cooperative Extension Service • Circular 6068

Figure 15. Finishing the front end wall of thehoop house.

Figure 16. Making a window on the back end wall.

Figure 17. Window completed; hoophouse completed.

To find more resources for your home, family or business, visit theCollege of Agriculture and Home Economics on the World WideWeb at www.cahe.nmsu.edu.

New Mexico State University is an equal opportunity/affirmative actionemployer and educator. NMSU and the U.S. Department of Agriculturecooperating.

May 2005 Las Cruces, NMElectronic Distribution May 2005