Building Our Greenhouse: Lessons from Our South Texas Farm

Jun 14, 2021by Juanita Schulze

Building a greenhouse on our South Texas farm taught us that getting a cover over your plants is only the beginning. Wind, heat, airflow, and the weight of equipment all affect how well a greenhouse works. Our first design gave us room to start seedlings, but it also showed us what needed to change.

This is the story of our early greenhouse and the taller hoop house that followed, with updates from our experience through the spring of 2023. It is a record of what we tried, not a set of engineered building plans.

Our First Greenhouse: Room to Grow and Plenty to Learn

Our original greenhouse measured approximately 14 feet wide by 80 feet long, with a height of about 5 feet 9 inches. We built the frame using 3/4-inch PVC pipe and covered it with greenhouse plastic. Inside, we had space for seed-starting shelves and a hydroponic system down the middle.

It was exciting to have room for so many young plants. But the low roof and lightweight frame created limitations, especially once wind, cooling equipment, and daily use entered the picture.

Ventilation Was One of Our First Challenges

We installed two large exhaust fans and later added two intake vents. The incoming airflow still did not match what the fans were pulling out. When the fans ran with the door closed, the plastic and roof pulled inward. Opening the door relieved the pressure, but that was not a dependable ventilation solution.

The lesson was clear: exhaust fans need adequately sized, unobstructed air inlets. A greenhouse that visibly deforms when its fans run needs its ventilation and structure reassessed before continued operation. We would not recommend copying that arrangement.

Wind, Frame Spacing, and Plastic Attachment

Wind exposed other weaknesses. On our first attempt, strong wind pulled the plastic off. We secured the clamps more firmly and reduced the spacing between supports from six feet to three feet, but the lightweight structure still needed improvement.

We also learned that the order of attaching the cover mattered. Securing both ends before working through the middle left parts of the plastic too tight, and it began tearing. Follow the covering manufacturer's instructions for attachment, tension, and installation conditions rather than treating our trial-and-error approach as a universal method.

Sandbags along the outside helped hold down the cover in our setup. However, holding down the covering is not a substitute for properly anchoring and bracing the frame. Pipe size alone does not establish that a greenhouse can withstand local wind or other loads.

Managing South Texas Heat

We added 30% shade cloth because our farm receives intense sunshine. We also used evaporative cooling, but our early setup could not keep the greenhouse comfortable as the weather warmed.

Shade, ventilation, and evaporative cooling each have limits. Cooling needs depend on the weather, humidity, greenhouse design, and the crops inside. Monitor conditions at plant level rather than assuming that running a cooler means the plants are protected from heat.

Water Supply and Hydroponic Lessons

Our greenhouse water supply came from the farm's well. We also kept a 2,500-gallon tank filled with well water as a backup.

At the time, we were encouraged by some of the water-test readings. However, those readings alone did not establish that the water could supply a complete hydroponic nutrient program. Hydroponic growing requires an appropriate nutrient balance and ongoing attention to water quality, pH, and nutrient concentration.

Keeping the hydroponic water cool during summer remained a challenge in the later greenhouse, even with substantial cooling equipment. The growing system needs its own temperature checks, not just a reading of the air inside the house.

Why We Replaced the Original Greenhouse

The first greenhouse did not last as long as we hoped. The 3/4-inch PVC frame lacked sufficient cross-bracing for our setup, and we placed too much weight on the supporting structure. These problems helped us recognize that our next greenhouse needed a different approach.

Our article's earlier update was dated January 9, 2021, and described the transition to a replacement greenhouse ahead of the 2021 growing season.

A Taller Hoop House and More Growing Space

For the replacement, we used 1 1/4-inch PVC pipe, spaced the hoops approximately two feet apart, and added about seven rows of strengthening supports. A misunderstanding about adding four feet to the structure gave us more height than originally planned. That extra headroom turned out to be a welcome improvement.

We designed the plastic covering so it could be lowered for additional summer ventilation. The revised setup included an intake fan and an exhaust fan, a better doorway, and more flexible growing space. In February 2023, we replaced the door with a standard household screen door.

We also changed the interior layout. Too much shelving limited our planting space, so we made room to grow inside as well as start transplants. During the spring 2023 season, we started approximately 4,000 plants, mostly tomatoes.

What Our Greenhouse Cost at the Time

Our original account estimated roughly $2,000 for the PVC hoop-house structure, compared with about $9,000 for a metal alternative we were considering. With electrical outlets, fans, evaporative coolers, and accessories, we reported a total investment of about $9,000. Approximately $4,000 of that total went toward evaporative coolers.

These are historical figures from our project, not current prices or a like-for-like construction quote. Materials, dimensions, installation, local requirements, and equipment can change a greenhouse budget considerably.

What We Would Tell Someone Planning a Greenhouse

Plan for your site. Consider wind exposure, drainage, access, and the conditions the structure must withstand. Use suitable plans and qualified advice for anchoring, framing, and bracing.
Design airflow before choosing fans. Intake openings and exhaust capacity must work together without pulling the structure inward.
Budget for heat management. Include ventilation, shading, temperature monitoring, and crop-appropriate cooling in the plan.
Keep equipment loads in mind. Do not hang equipment or add weight unless the structure is designed to carry it.
Plan utilities safely. Have electrical work and underground utility arrangements handled according to applicable requirements by qualified professionals.
Leave room to work. Headroom, walkways, watering access, and flexible bench arrangements matter when thousands of seedlings need daily attention.

For a broader checklist covering site selection, frame and covering choices, interior layout and seed-starting, read Build Your Own Greenhouse: Planning, Materials, and Growing Tips.

Learning as We Grow

Our greenhouse story includes mistakes, adjustments, and a few unexpected improvements. Each growing season helped us understand the farm better and make more practical decisions. The biggest lesson was not to copy a design simply because it worked for someone else, but to match the structure and growing system to the demands of the site.