Drip irrigation

Economical and ecological, drip irrigation is the solution of choice in the garden and even on a balcony. Coupled with a programmer, you will no longer have to worry about watering your plants so that they are beautiful and healthy!

What is drip irrigation?

• It is a low-pressure micro-irrigation system that starts with a simple water tap that feeds the main circuit consisting of a pressure reducer, a hose that carries the water to the plantations (diameter 16 to 25 mm), and then secondary circuits that can be made with thinner hoses (diameter 4 to 6 mm). The available hose lengths range from 5 to 100 m.
• Drip irrigation is usually coupled with a programmer that allows you to plan the watering times. The connected programmer offers even more freedom to the gardener.
• Note that there are watering kits that do not require a faucet or electricity. They are interesting in isolated areas or in the context of an unoccupied second home. They work from a rainwater collection tank, by gravity. The programmer is powered by batteries or even a small solar panel.

The dripper, the star of micro-irrigation

Watering each plant directly at its foot by drip is the goal of this micro-irrigation watering. To do this, drippers are placed on the pipes, with a fixed or adjustable flow rate, they allow you to irrigate each plant according to its needs by providing water progressively, drop after drop (from 0 to 20 liters per hour).

Note that the drippers can be placed directly on the first circuit if the watering plan is linear and/or on the secondary circuit.

From the simplest with a fixed flow rate to drippers whose flow rate can be adjusted by rotating the head, the choice is vast. The most fastidious will turn to professional solutions such as self-regulating drippers that compensate for a too low or too high pressure to deliver the required amount of water. These drippers will also solve the problem of a very sloping ground but be careful: often, they cannot be closed if a plant disappears unlike the adjustable drippers.

There are also built-in drippers for simplicity, but they do not allow the same creativity as a system where the gardener chooses to install his drippers according to the positioning of the plants already in place. Built-in drip lines have a spacing of 15, 30 or 50 cm, so it will be necessary that the garden is not yet planted or that the plants are exactly at these spacings for the system to be effective. However, this type of hose is easier to install and saves a lot of time.

What are the advantages of drip irrigation?

• This type of irrigation is very localized and ensures the preservation of water resources, the interest is both ecological and economic. Indeed, we count a saving of about 25 to 40% compared to a traditional watering for an efficiency 40 to 50% higher.
• The plants are watered at the right dose and in a regular way, which avoids the hydric shocks which weaken them in case of forgotten watering.
• The water is brought under low pressure to the feet of the plants and penetrates slowly towards the root system which benefits directly from it.
• The foliage is not watered, which avoids many cryptogamic diseases or leaf burns.
• The possibility of programming the watering offers a newfound freedom for the gardener who can finally go on vacation or take care of other activities.

How to install an efficient drip irrigation system?

Flow rate and pressure are the basic concepts of drip irrigation.

• Depending on the diameter of the hose, the flow rate will be more or less important. It is therefore crucial to calculate the necessary flow rate for the number of drippers installed and the length of the pipes.
• The flow rate of each dripper is given for a pressure of 1 bar (achievable thanks to the pressure reducer installed at the faucet outlet). For example, if you want to install 10 drippers with a flow rate of 2 l/h and 20 drippers with a flow rate of 4 l/h on your circuit you will need a total flow rate of 100 l/h. It is always better to limit yourself to a maximum of 50 drippers per circuit.
• A 16 mm diameter pipe will be chosen for a circuit of 50 to 100 m length, beyond that a 20 mm diameter pipe will be necessary so that the flow is always correct at the end of the circuit.
• Always differentiate between circuits with drippers and circuits with sprinklers. To do this, you can divide your irrigation plan into several circuits using directional elbows, bypass tees, plugs to complete a circuit...
• Don't forget to think about the solenoid valves needed to create several separate circuits. These solenoid valves, placed at the beginning of each circuit, are programmable. They work either under electrical tension via a programmer, or individually thanks to batteries. The solenoid valves allow you to operate each circuit independently.
• If your irrigation system has only one circuit, a timer will be installed just below the faucet to control the frequency, duration, and timing of watering automatically.

What is the best frequency to program a drip irrigation?

Watering should preferably be scheduled in the late evening after sunset so that evaporation is reduced and the plants get the most out of the water.

If each dripper corresponds to the real need of the plant, the watering can be started during one hour every evening in summer. In dry and hot weather, it can be extended by one hour. Only experimentation will help you decide on the duration and frequency, as each garden is exposed differently and exploited in different ways (presence or not of mulch, weeds...). It's up to you to learn how to dose, and to enjoy your tranquility!

Equipment for automatic watering

Automatic watering allows you to program a regulated irrigation according to the specific needs of the plants. It will also save you the chore of watering which can quickly become a hassle, especially in summer.

Automatic watering: what you need to know

The quality and diameter of the hoses chosen are essential parameters when installing an automatic watering system. Flexible or semi-rigid hoses must be able to withstand a pressure equal to or greater than 6 bars because they will be equipped with water intakes that will then carry the various types of sprinklers.

The hoses must be of very good quality in order to be assured of a long life, to resist to the climatic hazards and to the possible rodents.

In general, 25 mm diameter pipes will be sufficient unless your network is very long or your flow rate is enormous, in which case 32 mm diameter pipes should be preferred. The larger the diameter, the lower the risk of pressure drop at the end of the stroke.

The different types of sprinklers

Sprinklers are chosen according to the plants and their needs. Drippers are preferred for vegetable gardens or ornamental gardens because their flow rate can be adjusted individually according to the needs of the plants grown, while turbine, oscillating or rotating sprinklers will ensure the watering of lawns.

Please note: the two types of sprinklers cannot be installed in the same circuit because the flow rates and spans are not at all similar. It will be necessary to create two separate lines.

The various circuits

When your garden requires several circuits with different zones and different types of sprinklers, it is necessary to divide the automatic watering into several separate circuits. In this case, a selector switch with multiple outlets should be placed on the water supply valve. If you do not have a large flow rate, you will also need to install solenoid valves to trigger the circuits one after the other. There are two models: battery-operated (9 volts) or wired (powered by 24 volts). Remember to respect the direction of water flow when installing.

The programmer

The programmer is used, as its name indicates, to program the hours and duration of watering. It can be equipped with a humidity sensor or an electronic rain gauge that will allow the automatic watering to start if the soil is too dry or simply to stop if it rains enough.

The micro-sprinkler for your garden

The Micro Sprinkler is a watering system particularly adapted to large flower beds and rock gardens.

The Micro Aspersion produces a very fine rain that waters at low pressure (it does not damage the flowers, even fragile ones) and over different distances quite wide (1 to 3 meters radius depending on the brand).

This one is very easy to install since all the pipes are on the surface, with connectors to be plugged or screwed: many parts are common with a Drip system (see sheet: balconies and terraces). However, never mix micro-sprinklers with drippers on the same pipe.

So, a programmer on the faucet, a piece of garden hose with fittings, a filter + pressure reducer, PE hose with a diameter of 13x16, ground spikes to hold the hose in place, a small shut-off valve at the end of the hose that will allow for easy draining in the winter (since the hose is on the surface, it is not protected from the cold)

Once the main 13x16 pipe is in place, simply create branches on small pipe (4mm or 4.6mm) to a support.

At the top of this support, the micro-sprinkler is screwed or plugged in.

Note that the small tube branches should be relatively short (generally not more than 1 meter) and that between the support and the micro-sprinkler, it is often possible to place an extension (to raise the micro-sprinkler according to the vegetation) and a small regulating tap (to adjust the distance of the jet).

A micro-sprinkler is placed every 2 or 3 meters or so (depending on the technical characteristics): the jets must cross each other, as one sprinkler must always try to water its neighbor.

Even if they water at a pressure of a few bars in fine rain, the micro-sprinklers can have a large flow (up to 100 liters for some). It is therefore not possible to place too many of them on a single pipe.

The main technical advantages of micro-sprinklers are, if compared to drip irrigation:

• Excellent watering coverage over a large area (for a rock garden for example). The drip only waters a strip of land about 60cm wide.
• less hoses to pass through the beds, it facilitates the maintenance/planting and reduces the risks of breakage.
• in a caricatural way, where 50 drippers are needed to water a bed, we obtain a much better water distribution with only 5 sprinklers.
• the sprinklers, in height, do not get blocked, contrary to drippers which can end up being buried in the very dense massifs.
• it is easy to move a sprinkler since it is always in branch of the main pipe on a support planted in the ground. As a remark, I would indicate that the solution of putting the sprinklers directly in the 13x16 pipe is not qualitative in terms of watering and can, in some cases, be defective very quickly (from the second year).
• finally, the micro-sprinkler system is aesthetic when it works (editor's note: you will tell me that it must work around 2:00 am, and that the visual aspect is not essential at this hour ....)

All this being very easy to install, I wish you a "good installation".

Micro-irrigation to save water

Micro-irrigation is an effective water-saving technique that offers a solution of choice for both gardeners and agricultural companies. With an incomparable efficiency, this system allows to water the plants at the right time and at the right dose.

What is micro-irrigation?

Developed in the early sixties, micro-irrigation ensures optimal distribution of water under low pressure directly to the feet of the plants concerned. Of course, already in ancient times, the issue had been addressed by the use of oyas, these porous buried jars that ensured effective watering close to the roots.

But let's go back to the current system which has the advantage of being able to be planned by cycles, according to the climatic conditions, and which allows to choose the flow intended for each plant.

Otherwise known as 'localized irrigation', this technology was created in Israel in 1959, when the advent of plastic pipes allowed its development. Patented in 1960, drip irrigation quickly took off in America and Australia. Nowadays, this system is recommended in arid countries and in hot climates. Unlike conventional irrigation, which waters the entire soil indiscriminately using maximum pressure, micro-irrigation provides water in a punctual manner, on a well-defined area of the soil and at low pressure.

What does a micro-irrigation system look like?

There are several micro-irrigation media, although drip irrigation is the best known and most widely used, especially by individuals.

• The drippers work under a pressure of 1 bar. Each dripper is fixed independently on the whole length of a pipe of 0,5 to 1,5 mm of diameter. With one or more holes for water flow, the dripper can be chosen or adjusted (depending on the model) to the right flow rate for each plant (from 0 to 20 l/h).
• Micro-sprinklers, micro-diffusers or micro-sprayers are generally used in arboriculture. They can be fixed on a stake and diffuse water on 40 cm by rotation of the cap with an adjustable flow from 0 to 60 l/h.
• Micro-porous pipes are perforated with a multitude of small holes from which the water flows at low pressure along the whole length.

Advantages of micro-irrigation

This controlled watering technique allows enormous water savings (25 to 40%) compared to flood or runoff irrigation techniques with an efficiency 40% higher.

• Micro-irrigation can be coupled with a programmer, or even a weather station or an application to manage the watering according to the real needs corresponding to the climatic conditions. You can even be notified in case of water shortage or technical problem.
• Evaporation is less, especially when the system is activated at the end of the day. It also helps avoid many cryptogamic diseases that spread through the watering of foliage.
• The hydric shocks so harmful to plants are avoided. Plants not stressed by the lack of water are more vigorous and less sensitive to parasites.
• In a large farm, it allows to reduce labor costs.
• The rooting of the plants is favored by this system.
• There are far fewer weeds, which avoids competition for cultivated plants and tedious and time-consuming weeding.
• This technique allows for the direct addition of fertilizer during watering in large-scale agricultural operations.
• Knowing that the water consumption of intensive agriculture corresponds to nearly 70% of the world consumption, that water resources are beginning to decline or even disappear in some areas, the problem of food security may become burdensome. Micro-irrigation helps to overcome this problem.

Disadvantages of micro-irrigation

Although few in number, there are some disadvantages to installing a micro-irrigation system.

• The cost can be prohibitive when it comes to irrigating a large plot of land. However, at the level of a medium-sized private garden (500 m²) or even better, a simple balcony or terrace, it is possible to obtain very affordable kits that will quickly pay for themselves.
• Another concern is the technical nature of the installation (calculation of pressure losses, installation of the pressure reducer, knowledge of the right pipe diameters, creation of the different circuits, adjustment of the flow rate of the drippers and their number, installation and adjustment of a possible programmer...) which can frighten the novice gardener or those who are not very handy.
• The drip system should be checked often enough because some drippers can be clogged, especially by ants or soil debris.
• Leaks and breaks are not impossible, especially after the brushcutter has been used! If you don't do your own brush cutting or mowing, always remember to tell the person in charge of this work that an automatic watering system is in place, otherwise your garden will be compared to the water games in Versailles as soon as the watering system is turned on!

The installation seen from the trenches

You have now the technical study in hand to realize your underground watering system. Now it's time to tackle one of the most difficult parts (for the arms...): the earthwork.

Let's see the steps and our advice for the earthwork for the installation of your underground sprinkler.

1/ The trenches

Make the trenches as shown on the plan

The width does not matter. A trencher makes cuts 9 cm wide and this is more than enough to pass pipes and sprinklers. If you are working with a backhoe, there are small buckets that make narrow trenches (so there is less soil to put back in place afterwards!). Finally, with a spade, there is no choice but to get the width of the tool.

Remove all the stones if possible.

In terms of depth, there are several opinions...

• I often advise 35 cm minimum (a little more than a spade).
• It is useless to dig at 60cm to protect yourself from frost. In some regions, if the winter is very hard, the ground can freeze very deeply. It is better to foresee anti-freeze systems as soon as the installation is done.
• The idea of putting the pipes at 90 cm to be sure that nothing freezes is very risky: the sprinklers are on the surface, and they will be damaged by the cold: it is therefore better to have the possibility of draining the whole installation. Moreover, at this depth, when it is necessary to intervene to modify or repair, it is very complicated. Think about the hole that will have to be made for a simple connection to be added.

Don't forget when opening the trenches to foresee the location for the manholes (see manhole picture).

2/ Setting up the pipe network

Unroll the polyethylene pipe at the bottom. In case of important presence of stones or pebbles, put a bed of sand under the pipes (in this case, dig deeper).

Install fittings and sprinklers.

DO NOT PLUG UP!

At the end of the line, do not put the plugs in yet. You must first send water into the pipes to clean them of all the debris that could have slipped inside. (see photo turbine380)

Screw in the plugs once this step is completed. Shim and adjust your sprinklers. Leave the system running and check ALL the connections.

There are no leaks after your installation? You can now fill in the gaps...a little...

3/ Locate the water network

3) If you have a 40 cm deep trench, put 20 cm of earth and then put a blue wire mesh. This will avoid piercing the pipes if you have to work on them in a few years: it will indicate the presence of pipes underneath. The blue color of this plastic mesh is important, it is a recognized standard for water (for information, green = telephone, red = electricity, yellow = gas).

4/ End of the earthwork

That's it, you can fill it in completely. Let the soil settle for several days before renovating the damaged lawn.

Technically, the trenches are not the most difficult part, but a well done earthwork allows an easy maintenance during the following years.

Underground irrigation programmers

The use of a buried automatic watering controller allows you to control the watering time at the most convenient time of the day. 

One of the most important ways to save water is to water only as long as you need to, when evaporation is lowest, i.e. in the middle of the night or early morning.

To do this, your underground watering system must include an important element: the programmer. It will allow your installation to start and stop at the desired time; it will control the solenoid valves, so that your garden is watered in successive sequences: we speak then of several networks or ways.

There are four main types of multi-network programmers:

1. The battery-operated programmer, connected to the solenoid valves by a cable with many wires. This is a choice to be reserved exceptionally for places where there is no power supply. Compared to other options, this product is quite expensive. (main manufacturer: RAIN BIRD).
2. The wireless battery or current programmer. This one is connected by waves to the solenoid valves. The installation is thus strongly facilitated.
3. On the other hand, it is still a very expensive product, but practically all suppliers are trying to develop this type of programmer. We can therefore hope that the prices will decrease in the years to come. (Main manufacturers: RAIN BIRD, GARDENA...).
4. The wall-mounted programmer, with a separate transformer (photo opposite), connected to the solenoid valves with a multi-core cable. This is the best quality/price ratio. There are, apart from the "first prices", very reliable models at around 75 Euros that can control up to 6 solenoid valves. The only problem is that these products must be installed indoors (garage, cellar, storeroom, etc.), near a power outlet, as the electrical transformer (220v/24v) is not protected from water projections. (main manufacturers: RAIN BIRD, NELSON...).

The wall-mounted programmer, with an integrated transformer, connected to the solenoid valves with a multi-core cable. This is the largest choice available on the market. There are all models (from 2 to 48 networks) and all prices (from 170 Euros for the big brands). These devices have the particularity to be in the standards for a wall installation outside, even in the rain.
They are also products that can be installed inside. The advantage is that there are less visible wires, the transformer being included with the programmer in a single box, with a door that can be closed. (see photo below)

Logically, the many existing models and the discretion in terms of wall installation make these products very often preferred by craftsmen. (Main manufacturers: HUNTER, RAIN BIRD...).

The purchase of a programmer should not be based solely on its price: it is the submerged part of the iceberg (the rest of the installation being buried) and you will use it frequently (changing the watering times according to the season for example).

So you need a model that is easy to modify.

More and more products are available with hundreds of programming options. Even if you don't need all of them, the more options a controller has, the easier it is to adjust if you only focus on what you need for your garden.

So don't necessarily look for the cheapest one that seems simple, as this may limit the use you want to make of it.

Finally, in addition to the notions of saving water, a programmer is obviously a comfort of use, like all the rest of an underground watering installation.

Note that there are now programmers accessible from your smartphone.