Demystifying the Watering Needs of Plants

One of the essential resources for life is undoubtedly water. Studies show that this resource is and will be increasingly threatened by the climate changes we are experiencing. It is not that there will be a shortage of water on the planet, but rather that it will not be distributed evenly across all regions that need it. Some regions will have plenty, even too much, while others will be deprived. Already, many people around the world are in precarious, even unsustainable, conditions when it comes to drinking water supplies. According to UNICEF and the WHO, in 2023, more than 2 billion people worldwide still did not have access to a safe source of drinking water.

A valuable resource under pressure

Here in North America, we are still privileged, to the point that we consume several times more per capita than other industrialized countries. Yet they live very well and don’t deprive themselves!

Take Quebec, for example, since I live there and like to talk about what I know. I am often consulted to provide solutions to municipalities struggling with drinking water shortages during heat waves. These hot periods, which are becoming longer and more frequent during the summer, will likely become the norm, and we will have to get used to them.

Unwelcome restrictions

This situation forces municipalities to regulate the use of drinking water to ensure that all citizens have an uninterrupted supply of high-quality water. But the problem is that restrictions come at a time when citizens need water most, to water their gardens and flowers. Faced with frustration, some people cheat, forcing the authorities to crack down. This is not pleasant or positive for either side. We must not forget that there are costs involved in treating water to make it drinkable!

However, this situation could be avoided if we understood how plants in nature water themselves at all times, even during droughts. That is exactly what I will try to explain in the following.

Water properly

First, I must say that I find it hard to imagine the phenomenal amounts of drinking water wasted when people water their gardens! I’m not talking about those who rinse their driveways or fill their swimming pools, no! I’m talking about those who have a very legitimate need to water their gardens and flowers. It’s normal to water your plants, but we have to ask ourselves if we’re watering correctly.

Just because we make the gesture of giving water does not necessarily mean that it has been beneficial for our crops! Take, for example, when you are thirsty. Will you be quenched if you pour 10 liters of water over your head? Maybe 20 liters? No! A 250 ml glass will do the trick if you drink it. It’s not the amount of water that counts, but where it is put!

By observing how plants function in nature, I recognized a fundamental principle that is present everywhere on the planet, which I have named: the oil lamp principle.

The invisible wick that nourishes plants

The principle behind how an oil lamp works is that the wick, made of a porous fabric, is soaked in oil, allowing the oil to rise to the top of the wick. This principle, whereby oil defies the law of gravity, is called capillarity. It is the principle by which a liquid can soak into a porous material and rise up along it thanks to what is known as “the surface tension of a liquid.”

How capillarity works

Water is a liquid and soil is porous! Groundwater can therefore soak into the soil and rise to the surface, just like oil rises to the end of a wick. This rise of water from the subsoil contributes significantly to the irrigation of plants. This constant rise of water reaches the roots of plants to provide them with a daily supply, especially during periods when there is no heavy rainfall. This is the case with most summer rains, which only soak the surface, where there are few roots to draw water from.

You will notice this capillary action when you water your indoor plants by placing water in the saucer. A large mature tree can sometimes need more than 200 liters of water per day! So where does it get this water if it doesn’t rain heavily for weeks? Why is the lawn never nice under a large tree? Because the tree’s root system draws water up from the subsoil before it reaches the surface, leaving the lawn lacking water.

Why does container gardening require more watering? Because there is no source of water from the ground in containers with a bottom, and because the distance between the underground water source and the plants is greater in containers on the ground. It’s like the wick in an oil lamp. The oil would never reach the top if the wick was too long.

Combating capillarity or encouraging it

When building roads or landscaping a patio or sidewalk, it is necessary to combat this capillary rise of water to prevent freezing and surface deformation. Coarse-grained materials such as sand and crushed stone are used as a foundation, as water cannot rise through capillary action in these types of materials. The finer the particles, the stronger the capillarity: clay or loamy soils allow water to rise more easily than sandy soils.

Engineers and landscape architects must combat capillarity, but in gardening and horticulture we must preserve it and even encourage it when it is deficient, as it is our insurance against drought. Soil drought occurs when the amount of water that evaporates and is consumed by plants exceeds the amount that can rise from the soil through capillarity.

Target the roots, not the surface: watering reimagined

Faced with this environmental reality, I quickly realized that watering only the surface was not enough to properly hydrate my crops. It is underground, where the roots are, that the lack of water really poses a problem. Improper watering leads to a lot of evaporation, a waste of drinking water, and, in many cases, a waste of time. The numbers speak for themselves: according to sources, up to 40-50% of the water used in sprinkler irrigation can evaporate or be blown away by the wind before it even reaches the ground. Even traditional hose watering can result in up to 30% loss, while a well-designed drip system still loses up to 15%. On a city-wide scale, these losses represent millions of gallons of drinking water wasted every day during hot periods.

In addition to these losses, excess surface moisture promotes the presence of slugs, stimulates weed germination, and creates an environment conducive to fungal diseases, especially if the foliage is wet. It’s impressive—and concerning—to think about the millions of gallons of drinking water wasted every summer, especially during heat waves, simply because our watering methods don’t target the roots.

Underground watering

Underground watering—as offered by the Logissol-O system—meets this water supply requirement by bringing water directly to the soil surface. This method of watering is not just used to water the roots, but also aims to restore the soil’s natural capillarity so that the plant can regain its autonomy in terms of water supply. Your plants’ water needs are therefore not met by watering, but rather by the fact that you have reactivated the natural capillarity. As a result, the small amount of water you use will mainly serve to reactivate the capillarity.

Through this watering method and a system designed to work with it, the eco-friendly practice of collecting rainwater becomes cost-effective. a 200-liter barrel of collected water can last for weeks to water our plants, as it is only used to restart the capillary action, which will then water our plants for a few days of drought without us having to do anything. It’s like night and day compared to traditional watering methods. If you also apply adequate mulch to the soil, you will increase your autonomy by reducing evaporation, allowing the capillary action to water your plants more effectively for longer.

A barrel is good… but underground irrigation is better

So, in the future, for municipalities, offering, encouraging, or subsidizing a rain barrel is not really the solution if citizens are not also offered a watering method that will prevent the barrel from emptying after the first watering. If there is no rain the next day, how can the barrel be filled without resorting to drinking water? In a budget plan for substantial drinking water savings during periods of drought, encouraging and subsidizing an underground irrigation system would be much more effective than subsidizing a rain barrel.

In addition, a system that brings water underground rather than to the surface allows you to water with water that has been naturally warmed by the sun, which is beneficial for plant growth. This type of system also allows for all types of fertilization, even granular fertilizers. Designed with the priority of being as environmentally friendly as possible, it can be made in part with reused household containers.

Understanding the environmental logic makes all the difference!

Try it out and let me know how it goes!

Happy gardening!