The extreme heat of July is not only punishing the terraces of the Marina Alta. It can also become a free and natural tool for improving the soil before autumn and winter crops. This is highlighted by the Xarxa Agrícola in its bulletin number 13, issued on July 9, 2026, where it suggests taking advantage of the hottest part of summer to apply soil solarization.
The technique is designed especially for those who have empty raised beds or are preparing plots where other vegetables will be planted later. The goal is simple: to use the summer sun itself to improve the soil without resorting to chemical products. As the Xarxa Agrícola explains, «The extreme heat of summer is a free and incredibly powerful tool that the sky gives us.».
What is soil solarization?
Xarxa explains that solarization is an agricultural technique that uses solar radiation to raise the temperature of the soil for several weeks. Its operation is based on combining humidity, heat, and a well-sealed transparent plastic.creating a greenhouse effect on the ground.
The Xarxa Agrícola defines it as «a completely ecological hydrothermal method that uses the solar energy to “cook” the pathogens, fungi, nematodes, and weed seeds that remain dormant in the soil».
The image is very graphic: the ground is covered for weeks so that the sun can do its work. The heat accumulated under the plastic allows the soil to be disinfected naturally. and prepare better conditions for the crops that will arrive after the summer.
July, the ideal time in the Marina Alta
The Agricultural Network identifies July as the key month to apply this technique in the region. With thermometers reaching record highs and many plots between seasonsThe dog days of summer offer the most favorable conditions for effective solarization.
The recommendation is to keep the plastic in place for a minimum of four to six weeks in full sun. That is to say, Take advantage of all of July and part of August so that the temperature can act on the soil layers before removing the cover at the end of summer.
Step-by-step instructions for solarizing a raised bed
The first step is to prepare the land properly. The Agricultural Network recommends till the soil and leave it fineBreaking up large clods and removing the remains of previous crops to achieve the flattest possible surface.
Next comes one of the fundamental points: irrigation. As the Xarxa warns, Plastic should never be placed on dry soilBefore covering the raised bed, it is necessary to water it thoroughly.
Water serves a dual purpose. On the one hand, It conducts heat better to the deeper layers of the soilOn the other hand, it activates seeds and fungi that remain dormant, making them more vulnerable to the increased temperature generated under the plastic.
The most common mistake is using black plastic.
One of the clearest warnings from the Agricultural Network is also the most useful for those who have never performed this technique. The plastic should be transparent, not black.The explanation is simple: "Black plastic absorbs heat on the surface, but does not transmit it; transparent plastic lets radiation through, creating a brutal greenhouse effect that easily exceeds 50°C."
The specific recommendation is to use thin, transparent polyethylene plastic, from about 100 to 200 gauge. Once spread, it should be well stretched over the surface of the bed.
Seal the edges well for it to work
The final step is to seal the edges. Simply leaving the plastic lying on the ground is not enough. The edges must be completely buried to prevent air or water vapor leaks. The better sealed the system is, the more effective the greenhouse effect will be. and the higher the temperature that accumulates under the plastic during the weeks of exposure.
Other benefits for the land
Solarization helps make nutrients more available for the next crop, according to an explanation released by the Xarxa Agrícola (Agricultural Network). When the plastic is removed at the end of summer, the goal is to find healthier soil, better prepared to receive autumn and winter vegetables. It's a way of working in favor of natural cycles., using the heat of the season.
Furthermore, the Xarxa highlights a very practical advantage for those who take care of gardens and raised beds. It can save many hours of pulling grass by hand during the winter, without having used chemical products to achieve it.
A simple technique for taking care of the territory
The value of this advice extends beyond a specific gardening practice. In a region where many terraced fields coexist with abandonment, smallholdings, and the difficulty of maintaining agricultural activity, this advice also has educational value. They bring sustainable techniques to those who still work the land or want to recover small plots of land..
The Xarxa Agrícola summarizes this philosophy with a final sentence: «Let's take advantage of what it gives us nature to take care of the territory».
