How to choose the right mulch film for your crop?

Mulch film is one of those things that many growers buy almost automatically, opting for black, standard thickness, and that's it. And then they wonder why their neighbour, who grows the same crop, has a better yield, less weeds, or earlier ripening. The answer often lies precisely in the choice of mulch film, as the colour, thickness, and type of film directly affect soil temperature, moisture, weeds, and even the appearance of insects.

What does mulch film actually do?

Before we get to the choices, it's useful to understand why it's used in the first place.

Mulch film lies on the surface of the soil and does several things at once. It reduces water evaporation from the soil, meaning plants retain more moisture between waterings, and the need for irrigation is reduced by up to 30-40%. It blocks light from reaching the soil below, thereby preventing weed seeds from germinating, so less time and herbicide is spent weeding. It regulates the soil temperature, depending on its colour, to either warm or cool it. It keeps fruit clean as they do not come into contact with wet soil, which reduces the incidence of rot and fungal diseases. And finally, it preserves the soil structure as rainwater does not hit the surface directly and compact it.

All of this together means faster ripening, higher yields and purer fruit. The difference between the mulched plot and the one without it is immediately visible in the field during the summer period.

The colour of the foil is not about aesthetics, it's about agronomy

This is the most underestimated part. The colour of the mulch film determines how much solar energy is absorbed, how much is reflected, and whether light even passes through to the soil. This directly affects the temperature of the root system and the behaviour of insects.

Black film It is the most popular and widely used. It absorbs solar energy and transfers it to the soil, thus warming the soil by 2 to 5 degrees compared to an unprotected plot. It is completely impermeable to light, which means excellent weed control without herbicides. It is good for tomatoes, peppers, cucumbers, watermelons, melons, and most vegetable crops in temperate and cooler conditions.

Transparent film It heats the soil most effectively of all colours, as it allows solar radiation to pass directly into the soil where it is absorbed and retained like in a greenhouse. The temperature under the clear film can be 5 to 8 degrees higher than without mulch. The disadvantage is that it lets light through, so weeds grow freely underneath it, and it makes no sense to lay it without prior disinfection or fumigation of the plot. It is used for early spring planting of crops or for solarisation of the soil before planting.

White and silver foil The land is heated by the sun, so it is useful in summer when there is a risk of root overheating. In addition, silver reflective foil has a special property: it reflects UV light upwards, thereby disorienting and repelling aphids and thrips, which reduces the transmission of viruses from insects to plants. For peppers, lettuce, and flowers in the warmer months, silver foil can be more cost-effective than black, even without the introduction of new pesticides.

Brown and green foil It's a compromise between black and transparent. It heats the soil solidly, better than black, and has a certain permeability to infrared radiation that stimulates germination and root growth. At the same time, it retains enough opacity to light to suppress weeds, which is an advantage compared to transparent. These films are popular for strawberries, potatoes, and early spring crops.

Thickness: how much is enough

The thickness of mulch film is measured in micrometres (µm), and often appears as an insignificant detail on price lists, but it directly affects how long the film will last and how easily it breaks during installation and removal.

Films up to 20 micrometres are the thinnest and cheapest, intended for single-season crops with a short vegetative period where the film is removed after one harvest. For lettuces, early spinach, or short vegetable cycles, this is quite sufficient.

Films from 20 to 40 micrometres are standard for most vegetable crops, tomatoes, peppers, cucumbers, and watermelons. They last one to two seasons and withstand standard field working conditions well.

Films thicker than 40 micrometres are for multi-season crops, berries, hops, some ornamental crops, and for greenhouses where the film is not removed seasonally. They are more expensive, but usually cheaper per season than changing thinner film every year.

Perforation: is it necessary

Some types of mulch film come with pre-made planting holes, which speeds up installation and ensures even spacing between plants. For larger areas that are planted mechanically, this is a logistical advantage. For smaller plots and manual planting, there is usually no difference.

There are also micro-perforated films which have tiny holes distributed across the entire surface, allowing for better gas exchange between the soil and the atmosphere. This is beneficial for crops sensitive to root suffocation or in soils that are difficult to aerate.

Biodegradable films: when it makes sense

Standard plastic mulch film needs to be collected and disposed of after the season, which is labour-intensive and expensive, especially on larger plots. Biodegradable films solve this problem by degrading in the soil after the season, eliminating the need for collection.

It sounds ideal, but it has limitations. Biodegradable film is more expensive to procure, its durability is somewhat weaker than polyethylene, and its decomposition rate depends on soil temperature and humidity, meaning it may remain longer than it should in dry conditions, and degrade prematurely in humid ones. For short-cycle crops on smaller plots where collection is strenuous, biodegradable film makes sense. For large areas with long-cycle crops, classic polyethylene remains more economically viable.

What does that look like in practice?

For spring planting of peppers and tomatoes in open fields in Vojvodina, medium-thickness black mulch film is the standard and a good choice. It warms the soil, suppresses weeds, and retains moisture.

If you have a problem with aphids and virus transmission, add silver foil or combine a black base with a silver top, which is offered by combined black-silver foils.

For planting lettuce or more delicate crops in summer when temperatures are high, white or silver film will prevent the roots from overheating.

For strawberries, brown or green mulch film with good heating and weed control yields good results through multi-season cropping.

And finally, if you find the foil tearing during installation or creasing during harvesting, it's likely that there are not enough micrometres for your working conditions. This is not saving money, it's a cost that is paid twice.