Thermal Resilience: 4 Ways to Sustain Plant Growth and Fruit Size
Summer is here, and heatwaves can pose a serious challenge for most crops, which may experience a dangerous physiological slowdown if preventive measures are not taken in advance. Excessive solar radiation and high temperatures directly affect the photosynthetic process by degrading chlorophyll and, consequently, impairing plant growth and fruit development. In fact, heat stress is estimated to reduce the photosynthetic efficiency of crops by up to 40%. Another striking figure: according to the Anecoop Sustainability Observatory, the heatwaves experienced in Spain in 2025 resulted in losses of more than €1.479 billion.
How do excessive sunlight and heat affect plants? When light intensity becomes too high, chloroplasts are unable to process all the energy they receive. This leads to a decline in photosynthetic efficiency, stomatal closure and reduced carbon assimilation. As the plant slows down its metabolic activity, its natural growth is also restricted.
The optimal temperature range for most crops is between 20 and 30°C. Temperatures above this range can seriously impair plant performance and growth.
For this reason, this post focuses on thermal resilience, which becomes particularly important during the months of intense heat. At MAFA, we approach this challenge strategically, following clearly defined steps and using targeted solutions designed to address the problem at its source. Specifically, we focus on four ways to sustain plant growth and fruit size.
Prevention first: strengthen cell structure before the stress occurs
The heat is already here. However, episodes of excessive heat are not new and tend to occur every summer. That is why prevention is so important. How? By preparing the plant in advance, strengthening its cellular structure and antioxidant system so that it is better equipped to cope with the excessive solar radiation experienced during the summer months.
A well-balanced nutritional strategy with antioxidant activity enables crops to neutralize harmful free radicals and protect their tissues, helping to prevent heat stress from compromising crop yield.
At MAFA, we work closely with growers to establish a preventive strategy that promotes crop resilience through balanced plant metabolism throughout the growing cycle. The result: well-structured fruits, even after exposure to summer heat stress. Our timing strategy includes:
Activating soil microbiology before critical stress periods.
Maintaining adequate levels of organic matter.
Avoiding nutritional imbalances.
Applying biostimulants at key physiological stages
Applying cellular thermoprotection mechanisms
What does this mean? Protecting plants against excessive heat is essential because high temperatures significantly increase the production of reactive oxygen species (ROS), which can damage cell membranes and reduce growth capacity. How can this be achieved?
Activating natural antioxidant mechanisms. At MAFA, we offer specific solutions designed to stimulate the synthesis of compounds that help neutralize oxidative stress, thereby protecting cellular integrity under extreme heat conditions.
Maintaining photosynthetic activity. This is essential because protecting chloroplast structure helps ensure that the plant continues to produce energy even under adverse environmental conditions.
Inducing heat-shock proteins. These essential proteins act as cellular protective mechanisms, helping prevent high temperatures from disrupting vital physiological processes.
Osmoregulation: managing water at the cellular level
This is particularly relevant when considering how thermal stress can affect fruit size. Since our objective is to maintain the expected crop quality and fruit calibre, we work along three main lines:
• Using protective osmolytes, i.e. molecules that facilitate water retention within cells, helping to prevent dehydration and plasmolysis. • Managing energy expenditure through amino acid-based biostimulants. This helps the plant restore metabolic balance without depleting its energy reserves. • Supporting tissue regeneration. By promoting the recovery of foliage and roots, we help maintain overall plant vitality and productive capacity.
Proper crop management during periods of peak stress
When temperatures and solar radiation reach their highest levels, crop management requires specific precautions, such as:
Applying foliar sun protectants, such as kaolin, 48 to 72 hours before a heatwave, which can generally be anticipated through weather forecasting services. This type of protection reflects solar radiation and can reduce leaf and fruit temperature by 3 to 5°C.
Efficient irrigation. As we know, scheduling irrigation in the early morning helps cool the soil and plant before temperatures rise. In addition, increasing irrigation frequency without causing waterlogging helps maintain plant turgor and prevents simultaneous water stress.
In short: heat-related damage can be minimized without triggering a physiological slowdown in crops or compromising fruit size. At MAFA, we help ensure that plants continue performing at their full potential, even when temperatures rise.
