Water Management
Sustainable Growing

Exploring the sustainable world of horticulture: Innovations and practices for commercial greenhouse growers

Grodan
July 19, 2024

Horticulture isn’t just about growing plants - it represents an opportunity for sustainable agriculture, particularly in the case of Controlled Environment Agriculture (CEA). This science-driven method involves cultivating all kinds of crops in high-tech greenhouses: from fruits and vegetables, to pot plants, flowers, and medicinal crops. In this blog post, we’ll dive into the innovative technologies and sustainable practices that are redefining horticulture, with a special focus on commercial greenhouse projects.

Key takeaways 

  • Horticulture combines the art of nurturing plants with scientific research to improve plant quality and yield, using specialised practices and high-tech greenhouses to optimise conditions for a variety of crops. 
  • Modern horticulture emphasises sustainability through regenerative practices that reduce resource use, combat climate change, and utilise smart greenhouse technology to sustainably produce crops all year round. 
  • Technological innovations support climate-smart agriculture. Technologies such as sensors, climate control systems, greenhouse irrigation systems and energy-efficient heating and lighting can all be critical to advancing healthy and sustainable food production and crop production.

The essence of horticulture 

What is horticulture? Horticulture is the science and practice of growing crops. This diverse field covers a wide spectrum of plant cultivation, ranging from fruits and vegetables to flowers, pot plants, and medicinal crops. What sets horticulture apart is its focus on enhancing plant production, both in terms of quality and quantity. In a commercial greenhouse project, a modern grower meticulously applies scientific principles, often taking advantage of innovative, climate-smart agricultural technology to produce superior crops. Growers supply these crops to customers nationally and internationally, all year round.  

Horticulture extends beyond mere plant growth to include a variety of specialised practices. One of these practices that is often performed in a commercial greenhouse is plant propagation: the process of controlled multiplication of plant species. In propagation, horticulturists adapt their approach to their specific goals and the unique characteristics of each plant, using either sexual or asexual methods to multiply plant species. From the substrate used to the specific climatic conditions, every aspect is meticulously managed to optimise plant growth and increase yield. 

The difference between traditional agriculture, horticulture, and Controlled Environment Agriculture 

Horticulture is a specialised branch of the broader, traditional agriculture industry. Examples of conventional agriculture include large-scale outdoor crop production and livestock rearing. Conversely, horticulture focuses on improving plant quality and yield, pushing for heightened agricultural efficiency and sustainability. This specialised subdivision of agriculture leverages innovative greenhouse technology and enables commercial greenhouse growers to push the scientific boundaries of plant cultivation. 

The advent of the high-tech greenhouse has transformed the field, leading to Controlled Environment Agriculture (CEA). This enables growers to precisely adjust and control growing conditions to produce superior crops all year round. Greenhouse production, utilising advanced growing systems, offers an attractive alternative to the often unpredictable conditions of traditional farming, especially in today's era of climate change. With the ability to control almost every external condition, from temperature and humidity, to light and water, horticulturists can create perfect growing conditions, leading to increased yield and productivity. 

The spectrum of horticultural crops 

The spectrum of horticultural crops includes a myriad of produce: from nutritional fruits and vegetables, to decorative flowers and pot plants, to medicinal crops that can be used as ingredients in pharmaceutical products. 

In recent years, innovations in greenhouse technology have further broadened this spectrum. For instance, recent trials by Grodan showed that strawberries can be propagated and cultivated on stone wool substrate while maintaining high quality and attractive fruit size. Such advances are continually expanding the spectrum of horticultural crops that can be cultivated in a Controlled Environment Agriculture environment. This is one way in which the horticulture industry contributes to securing the sustainable future of an ever-growing variety of plants as food and medicines for the world's population. 

Sustainable practices in modern horticulture 

Modern horticulture focuses on sustainability by creating closed-loop systems designed to save resources, cut down on waste, and reduce the carbon footprint. Amid increasing concerns over climate change and resource scarcity, sustainable practices have become paramount in the horticulture industry. Today’s high-tech greenhouses are designed to deliver ideal growing conditions while making optimal use of the available resources and minimising the impact on the environment. 

Horticulture is making strides in combating climate change, including: 

  •  'Rewilding' nature, as Controlled Environment Agriculture requires less fertile land, creating more natural habitats for a balanced ecosystem 
  • Implementing sustainable supply chain management for the handling of products such as packaging materials, substrates, and end products 
  • Emphasising water efficiency in irrigation practices, employing novel growing systems that cater to the plants’ needs 
  • Utilising the high-tech greenhouse as a mini ecosystem where sustainable practices are the norm 

These approaches reflect a shift towards sustainable food production in the horticulture industry. 

Innovations in greenhouse technology 

With rising demand for fresh, sustainable food and decreasing availability of fertile land and labour, technological innovations are crucial to solving crop production challenges. Greenhouse technology is drastically changing our approach to plant cultivation. High-tech greenhouses are equipped with smart sensors, climate control systems, energy-efficient LED lighting, and high-tech water and nutrient management systems. These features mitigate environmental impacts, ensure optimal growing conditions year-round, reduce energy and water consumption, and promote sustainability in horticulture, all while guaranteeing high-quality crops and a consistent supply of fresh, healthy, local produce. 

Light optimisation for growth 

Light, which controls flowering and influences overall development, plays an essential role in plant growth. Greenhouses optimise light exposure, which is crucial for maximising plant growth and yield. In periods of low natural sunlight, such as at nighttime or the winter months, growers can use artificial lighting in the greenhouse to promote the growth of high-quality crops. In the case of too much sunlight, which could damage the plants, growers can use screens or a coating to block or diffuse the light. By combining natural sunlight with controlled climate conditions, a greenhouse can achieve more efficient plant growth than in outdoor environments. 

Supplemental lighting in a greenhouse aids in achieving full crop potential while reducing the reliance on sunlight. Some benefits of using supplemental lighting in greenhouses include: 

  • Ensuring an even distribution of light 
  • Preventing hot spots 
  • Minimising plant stress 
  • Creating ideal growing conditions 
  • Maximising crop yield and quality 

Light optimisation techniques contribute to the creation of ideal growing conditions in greenhouses, maximising crop yield and quality. 

Harnessing climate control for year-round production 

Besides lighting, intelligent climate control devices such as smart AC controllers automate temperature management, enabling remote adjustments and custom temperature settings for different times of the day. Energy efficiency is further enhanced in greenhouses with energy screens, which trap in as much heat as possible and prevent it from escaping through the roof. Other solutions for lower energy consumption include films like infrared anti-condensate polyethylene. 

For optimal plant growth, it is critical to maintain the correct temperature in a greenhouse. Growers can use a range of temperature regulation techniques, including insulation, shading, and ventilation, to achieve this. For instance, climate-controlled greenhouses often incorporate twin-wall polycarbonate cladding that effectively retains heat, helping to maintain ideal temperatures and improve energy savings. Additional greenhouse insulation tactics, like utilising silicone caulk for sealing gaps and applying bubble wrap or plywood on certain walls, can play a crucial role in heat retention during winter. 

To combat excessive heat, a greenhouse can utilise shading options such as screens or coatings that filter the sun’s intensity. Passive ventilation aids in temperature control and air circulation without the higher costs associated with active systems such as mechanical ventilation.  

By integrating various systems to control temperature, humidity, light levels, irrigation and more, climate-controlled greenhouses have revolutionised horticulture, enabling year-round crop production. These greenhouses enable growers to maintain optimal growing conditions, irrespective of external weather variations boosting crop growth and fostering sustainability in horticulture. 

Smart energy management in greenhouses 

For sustainable horticulture, energy conservation is of utmost importance. Nowadays, horticulture operations are increasingly turning to renewable energy sources such as solar panels to decrease their dependence on fossil fuels, thereby cutting down on greenhouse gas emissions. Additionally, energy-efficient strategies are being implemented in modern greenhouse production to minimise energy consumption. From adopting electric, battery-powered machinery, to adjusting climate control strategies based on external weather fluctuations, horticulture is making strides in energy conservation.  

Some strategies for energy management in the greenhouse include: 

  • Using hydronic heating systems with hot water pipes underground, controlled by a temperature sensor, to efficiently manage greenhouse heating 
  • Replacing incandescent lamps with compact LED lights to reduce energy use associated with artificial lighting 
  • Implementing cyclic lighting to optimise energy usage 
  • In addition to these strategies, there is a growing focus on the transition towards a low-carbon economy. Companies like Grodan are committed to taking further steps towards this goal, with projects in the pipeline to convert production lines to an innovative electric melting technology based on low-carbon electricity. Such initiatives reflect the concerted efforts of the horticulture industry to reduce its carbon footprint and promote environmental sustainability. 

By implementing these energy-efficient heating solution strategies and utilising methods to store energy, greenhouse owners can reduce their energy consumption and operate more sustainably. 

Irrigation and water conservation 

Sustainable horticulture greatly depends on efficient irrigation systems and water management practices. The adoption of high-tech hydroponic (water-based) systems in modern horticulture and vertical farming allows for efficient use of water through soilless cultivation and the treatment and recycling of water and nutrients. The right substrate, such as Grodan's range of stone wool growing media, forms an important starting point for this. Additionally, selecting the proper irrigation methodology in the greenhouse, such as boom, drip or micro-irrigation systems, is vital for maximising water efficiency. These systems need high-quality water to function effectively, which growers achieve by installing a water purification system as part of their greenhouse project. 

Routine system maintenance and audits of the irrigation setup help in pinpointing inefficiencies leading to more uniform water distribution and substantial water conservation in horticultural practices. A clean and uniform substrate from Grodan contributes to keeping irrigation systems cleaner, since stone wool growing media do not contain natural fibres that can become loose and enter the system.  

Conserving water, another critical resource in horticulture, is of prime importance. Modern growers are adopting circular economy models to maximise the recycling and reuse of water, addressing their role as a primary group of consumers of fresh water resources. 

To contribute to fresh water conservation, a greenhouse can also employ the following sustainable practices: 

  • Automated rain water harvesting systems that capture irrigation runoff 
  • Advanced water treatment methods, like reverse osmosis, to ensure the safety and quality of recycled water for horticultural irrigation 

By implementing these practices, a greenhouse can reduce its reliance on fresh water supplies and play a significant role in global water conservation efforts. 

Big data is also a factor here, offering personalised and localised insights which can help growers to identify optimisation opportunities within the greenhouse. Intelligent irrigation and water management practices can considerably lessen the water footprint of horticulture.  

Root zone management and nutrient management 

Plants need nutrients in order to thrive, in addition to water, heat and light. Hence, implementing effective root zone management and nutrient management strategies is critical for optimising crop yield and fruit quality. The choice for substrate, which serves as the medium for root growth and nutrient absorption, is made prior to the start of each cultivation cycle. For example, Grodan’s NG 2.0 substrates, made of hydrophilic fibres, offer high irrigation efficiency and do not lock in any nutrients, ensuring that plants get the nourishment they need. 

Plants require 16 elements for growth, including: 

  • Carbon 
  • Hydrogen 
  • Oxygen 
  • Nitrogen 
  • Phosphorus 
  • Potassium 
  • Calcium 
  • Magnesium 
  • Sulphur 
  • Iron 
  • Manganese 
  • Boron 
  • Zinc 
  • Copper 
  • Molybdenum 
  • Chlorine 

These nutrients can be divided into macro and micro nutrients, with each having specific roles in plant development. Ensuring the right balance of these nutrients in the root zone is fundamental for healthy plant growth. Monitoring these nutrient levels using sensor systems like the GroSens system provides valuable insights for managing the growth strategy. 

Market trends and consumer preferences 

The horticulture industry is significantly shaped by market trends and consumer preferences. Factors such as demographic shifts, environmental concerns and the rising use of social media influence these trends and preferences. For instance, consumers are becoming increasingly critical of how and where their food has been produced, indicating a demographic-driven trend towards more sustainable horticulture. 

Another trend is the ongoing shift away from eating meat and dairy-based products towards a vegetarian, flexitarian, or vegan diet. Platforms like Facebook, YouTube, and Instagram serve as significant channels for discovering new recipe ideas and lifestyle choices, significantly influencing consumer preferences that are creating an even brighter future for horticulture. 

By gaining an understanding of and responding to these trends and preferences, horticulture businesses can serve their customers better and achieve success in the market. 

Government regulations 

Over the past two years, government regulations have increasingly impacted the sector, reflecting a growing emphasis on sustainability and food safety: 

In 2022, the European Union implemented stricter pesticide regulations under the Farm to Fork Strategy, aiming to reduce chemical pesticide use by 50% by 2030, which directly affects horticultural practices.  

Similarly, in the United States, the FDA's Food Safety Modernization Act (FSMA) has introduced more stringent compliance requirements for produce growers, focusing on preventive controls and safety standards to mitigate contamination risks.  

These regulations enhance the appeal of greenhouse growing over traditional open-land agriculture, as greenhouses naturally require fewer pesticides and reduce contamination risks due to their controlled environments.  

Additionally, various governments have launched incentives and subsidies to promote the adoption of renewable energy and water-efficient technologies in horticulture, aligning with broader climate action goals. These regulations are shaping the future of horticulture by pushing for greener, safer, and more innovative agricultural practices. 

United States 

  • Environmental Quality Incentives Program (EQIP): Offers financial and technical assistance to agricultural producers to plan and implement conservation practices, including those that promote sustainable horticulture. 
  • Sustainable Agriculture Research and Education (SARE): Provides grants and funding for research and education projects that promote sustainable farming practices. 

European Union 

  • Common Agricultural Policy (CAP): Provides subsidies and support for sustainable agricultural practices, including specific measures aimed at promoting environmentally friendly horticulture. 
  • Horizon Europe: Funds research and innovation projects, including those focused on sustainable agriculture and horticulture. 

Australia 

  • National Landcare Program: Offers grants and support for sustainable farming practices, including horticulture, to improve soil health, water quality, and biodiversity. 
  • Sustainable Agriculture Small Grants: Provides funding for farmers and organizations to implement sustainable practices and innovative solutions in agriculture. 

India 

  • Paramparagat Krishi Vikas Yojana (PKVY): Promotes organic farming and sustainable agricultural practices by providing financial assistance to farmers for adopting organic farming methods. 
  • Mission for Integrated Development of Horticulture (MIDH): Provides financial assistance and support for the adoption of sustainable practices in horticulture, including organic farming and integrated pest management. 

Canada 

  • Agricultural Clean Technology (ACT) Program: Offers funding to support the development and adoption of clean technologies in agriculture, including sustainable horticulture practices. 
  • Canadian Agricultural Partnership (CAP): Provides funding and support for sustainable agricultural practices, including projects that enhance environmental sustainability in horticulture. 

New Zealand 

  • Sustainable Farming Fund (SFF): Provides funding for projects that improve the sustainability and productivity of New Zealand's horticulture and agriculture sectors. 
  • Horticulture New Zealand's Future Orchards program: Offers resources and support for adopting sustainable practices in orchards.  

Adapting to climate challenges 

Horticulture faces significant challenges from climate change, as abiotic stressors like extreme temperatures, precipitation events, floods, droughts, salinity, heavy metal toxicity, UV damage, and air pollution increasingly impact outdoor crop production. In order to surmount these challenges, horticulture is adopting sustainable practices, developing resilient crop varieties, and enhancing indoor growing practices. Protective structures such as greenhouses can play an important role in mitigating the effect of extreme weather conditions caused by climate change. Thanks to Controlled Environment Agriculture, the horticulture industry can continue to thrive, even in the face of climate challenges.

Partnerships are key 

Collaboration in the industry is also playing a key role in addressing the diverse challenges within the horticulture sector. For instance, Grodan - a manufacturer of stone wool growing media, sensors and data solutions for root zone management in horticulture - collaborates with other leading suppliers in the industry. Within these partnerships, Grodan organises research trials and real-life trials with growers. The resulting knowledge is shared with growers and stakeholders as content such as guidelines and advice, and also transferred during industry events.  

For example, in a recent research trial, 2 different irrigation treatments were combined with LED lighting and active air dehumidification. The aim was to explore how plants perform and can be steered in these conditions, and the trial produced some valuable information. Such collaborations and innovations are helping to make energy management smarter and more efficient in greenhouses. 

Summary 

In conclusion, horticulture is a diverse and dynamic field that merges science and technology to cultivate a myriad of crops for food and medicines. Thanks to the sustainable practices supported by high-tech greenhouses, modern horticulture is leading the way in innovative and environmentally friendly plant cultivation. By harnessing technology and adapting to market conditions as well as climate challenges, it continues to evolve towards a greener and more sustainable future for us all. 

Frequently asked questions 

What are examples of horticulture? 

Examples of horticulture include vegetables, fruits, flowers, plants and medicinal crops. These crops can be cultivated on a large or small scale. 

What is the difference between horticulture and agriculture? 

Horticulture encompasses the cultivation of plants for food and medicines, and can also include the cultivation of plants and flowers for aesthetics. Agriculture covers the large-scale farming of livestock as well as crops for food and feed purposes. Some people view horticulture as a subset of agriculture. 

What do you mean by the term horticulture? 

Horticulture refers to the branch of agriculture focused on growing plants for food, medicines and aesthetic purposes. It encompasses the cultivation of plants for human use. 

What does a horticulturist do? 

Horticulturists are trained professionals who oversee and improve the growth of food crops, ornamental crops and medicinal crops. Some horticulturalists work outdoors in the field, while others work indoors in a greenhouse.  

What differentiates high-tech horticulture from traditional agriculture? 

High-tech horticulture differs from traditional agriculture by focusing on enhancing plant quality and yield through specialised techniques and technologies, such as greenhouse technology, automation, data management, and other innovative solutions. This allows for increased efficiency and sustainability. 

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Low-heat full-LED tomato trial achieves 50% reduction in heat

To help growers find a solution for cultivating a full-LED winter lit crop with a low heat input without impacting on yield or quality, Philips Horticulture LED Solutions and Grodan ran a joint trial at Botany Research Center, the Netherlands. The trial, which used active air dehumidification, has demonstrated that controlling and optimising all the aspects in a greenhouse enables a lower heat input to be realised while enabling sufficient transpiration to support strong and healthy crop production. In fact, the final results were even better than expected: the heat input was reduced by more than 50%.

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Why stone wool stands out in indoor strawberry cultivation? The choice for growing media is made prior to the start of each cultivation cycle and is important to achieve the most from a crop, specifically for strawberry cultivation. Trials conducted at research centres in the Netherlands concluded that growing in stone wool growing media for high-tech glasshouse cultivation does improve growing results. So why to switch to stone wool? Thomas Peters explains further in the whitepaper : “Optimising water and nutrient management in strawberry cultivation”.