Plastic or glass? The real question is how much control the crop needs

Plastic greenhouses remain the most widely used type of greenhouse and have played a fundamental role in the development of Spanish horticulture for decades. Their relatively low initial investment, flexibility and suitability for the Mediterranean climate make them a logical solution for many growers. At the same time, climate change is making growing conditions increasingly unpredictable, increasing the importance of being able to control the climate inside the greenhouse.

But conditions are changing. Water availability, input costs, extreme temperatures and market requirements are forcing growers to look beyond the initial cost of a greenhouse. That is why the question should not simply be: plastic or glass? The real question is how much control the crop needs to produce profitably and predictably.

Plastic still has its place

There is no single type of greenhouse that is suitable for every grower, crop or region.

Plastic-covered greenhouses dominate a large part of Mediterranean protected horticulture. They make it possible to create large production areas with a competitive initial investment and have contributed significantly to the growth of the horticultural sector in Southern Europe. For certain crops, cropping cycles and business models, they remain a good solution.

At the same time, plastic greenhouse covers have a limited service life. Their optical properties can also change during use due to factors such as ageing and the accumulation of dirt. In addition, plastic-covered greenhouses provide a lower level of insulation, making them more sensitive to external climatic conditions.

For growers looking to increase the level of climate control, extend cropping cycles or improve production predictability, it may therefore be worth considering other options.

Glass is only the beginning

A glass greenhouse provides a durable structure and a solid foundation for high-tech production. But attributing all the benefits to glass alone would be too simplistic.

The real change happens when the greenhouse structure, climate, water, energy, CO₂ and cultivation strategy work together as one integrated system.

This is also KUBO's approach. With KUBO's Ultra-Clima® concept, for example, the greenhouse combines different technologies to create a more stable and controllable climate around the crop. The goal is not to add technology for the sake of it, but to give growers more tools to manage growing conditions accurately and efficiently.

This changes the way the investment should be evaluated.

Greater control over the climate

In a system with a higher level of climate control, growers are less dependent on external conditions to maintain the right environment inside the greenhouse.

Temperature, humidity, air circulation and CO₂ concentration can be managed more precisely. This makes it possible to maintain more stable growing conditions when the climate outside changes.

This is particularly relevant in a Mediterranean climate. High solar radiation is an advantage for production, but it also creates challenges related to temperature, humidity and cooling.

However, the solution is not to copy a Northern European model and transfer it directly to Spain.

Every project should be designed around the local climate, the crop, the availability of water and energy, market conditions and the grower's economic objectives.

Water, energy and CO₂ as part of the same equation

The greater the level of control inside the greenhouse, the more opportunities there are to manage resources as one integrated system.

In a concept such as Ultra-Clima®, water, energy, climate and CO₂ are all part of the same production strategy. The objective is to find the right balance between yield, quality, resource consumption and operating costs.

This becomes particularly important when water and energy are no longer considered simply as costs, but as factors that determine production capacity.

Looking beyond the price per square metre

A high-tech glass greenhouse requires a higher initial investment than many plastic greenhouse structures. This is a factor that should not be overlooked.

However, comparing only the investment per square metre does not provide the full picture either.

An investment decision for a high-tech greenhouse such as Ultra-Clima® should take into account much more than the initial cost. Factors such as marketable yield per square metre, product quality and uniformity, the length of the production season, water and energy consumption, maintenance requirements, production risk and the ability to supply the market consistently also play a fundamental role.

In other words, it is not simply about how much the greenhouse costs to build.

It is about the value it can generate throughout its entire service life.

From greenhouse to production strategy

The future of Spanish protected horticulture will probably not be exclusively plastic or exclusively glass. Both systems will continue to have their place.

The question for each grower is what level of control and technology will be required over the next ten, twenty or thirty years of productive life.

For KUBO, the starting point is not to sell more technology. The first step is to define what the crop needs and what results the grower wants to achieve. From there, the right system can be designed around those requirements.

It is not simply about choosing between plastic and glass.

It is about choosing the level of control the crop needs and the business model the grower wants to build.