Installation of a solenoid valve manhole for an underground irrigation system

Here is an illustrated example of a solenoid valve assembly in a manhole. This one, as well as those that could follow, is only an example among many solutions or preferences that each installer may have. Nevertheless, some basic principles are stated.

1/ Mounting the manifold

Here two solenoid valves with the water inlet in the center. Although there is a main water cut-off, a shut-off valve is always placed at the manhole inlet. The solenoid valves are removable before and after, by the "removable union" type fittings. The solenoid valves have been disassembled so as not to bother with the wires, protective tape (orange here) prevents the intrusion of earth. Pipe primers allow the manifold to be mounted completely without worrying about the rest of the piping.

2/ Positioning the collector

After the hole has been made for the manhole (wider than necessary), the bottom is laid flat, the solenoid valve manifold is placed, as well as a sheath here to allow the cable to be passed later. The pipes under the manifold allow to raise it a little with respect to the level of the manhole (the usefulness of this will be seen later).

3/ Arrival of the manhole

The manhole has been cut with a hole saw in order to let the pipes pass. It is positioned over the collector. We check that it is level and aligned with the limits of the garden (wall, alley, ...). Note that the manhole is deliberately larger than necessary: it is a false economy to try to put a maximum number of valves in a small manhole; maintenance and repairs are difficult, the connections are not accessible, ...

4/ Wedge the manhole

Once the manhole is correctly in place, we start to backfill all around it, gently so as not to shift it. The geotextile film is pulled up along the outside walls so that the soil does not enter the manhole.

5/ Backfilling

Once the manhole is in place, it can be completely filled in. The pipe primers are useful on some sites where the manholes are installed well before the garden pipes.

6/ Manhole bottom 

The bottom of the manhole is filled with pebbles. The pieces of pipe which supported the collector are removed.

7/ Cleaning

The manhole is cleaned with water. All the components of a collector are watertight, so it can be washed with water. The solenoids are screwed -by hand- on the solenoid valves, the wires will not interfere anymore. The multi-core cable coming from the programmer is brought into the manhole, longer than necessary (it will not be cut).

8/ Connections

All that remains is to connect the wires of the solenoids with the cable, using waterproof connections. Here, the connections are enclosed in a box, for cleanliness reasons, so as not to leave unsightly connections lying around: be careful, it is never the box that makes the watertightness, but the specific connections used.

Renovation of a solenoid valve manhole for underground watering

Here is an example of a manhole installation using existing cables or pipes.

1/ Assembly of the new manhole

After the old manhole with its solenoid valves has been completely dismantled (the cables are not cut, it is better to keep the connections), a new complete manifold is assembled, adapting to the existing one.

Here, three watering networks, drip, so three solenoid valves. A stop valve was added at the entrance of the collector, as well as a second valve to easily purge the collector before the winter.

This is a solution that I recommend very regularly (even if it is not systematic). Removable fittings before and after the solenoid valves.

2/ The manhole

We check and try the positioning of the manhole. In renovation, it is always a little more complex than in a new creation. It is necessary to check that a maximum of elements and connections are inside the manhole (and not under the edges, the walls, inaccessible).

3/ Connections

The manhole has been installed, wedged and filled, it is time to make the watertight connections.

Here you can see the old connections (brown), which have not been removed in order to identify the wires as the new connections are installed (blue or black).

4/ Finishing

Once finished, a bottom of garviers or pebbles, then we wash the manhole; the old grey cable has not been shortened, and there is room in this large manhole to work if needed.

Automatic drip irrigation by gravity

If you don't have electricity and water near the area to be watered or you don't want to use it because it is your second home and the taps are closed and the fuses are broken when you are away, automatic gravity drip irrigation can be a solution for a self-sufficient system, but it has some implementation constraints.

Having a water tank

Automatic gravity watering requires a rainwater reservoir or a tank filled regularly with water when you are present intermittently. Its volume will depend on your autonomy. A tank of one cubic meter is a good starting point and will ensure several weeks of watering depending on your surface to cover. By connecting several tanks you will increase this autonomy. 

The advantage of the water tank in the case of a second home is to leave with peace of mind with the water meter valves closed. Who hasn't experienced a leak on his watering system?

Severity and pressure

In this type of watering, the idea is to take advantage of gravity to feed our drip system. Under its effect, the water will flow in your network which must be under the water level of the tank. In fact, a buried tank on a flat ground will not be suitable without a pump and therefore with electricity nearby.

But for the drip system to work at its best, pressure is needed to feed and distribute the water throughout the network. This is related to the height of the tank and more precisely to the height of the water level, placing the water tank as high as possible will be an asset. If your land is flat, you should consider raising the tank by a slope, a small construction, some breeze blocks or pallets, if your land is sloping, simply place it in the upper part of the garden.

The pressure is 1 bar every 10 meters vertically (editor's note: information well known to divers), a meter of difference in level between the tank and the watered area makes you gain 0.1 bar of pressure. This is only an order of magnitude, but it is important when it comes to solenoid valves.

To facilitate the flow, bring the water as close as possible to the area to be watered with large diameter pipes starting with 25 mm for example and then create a secondary network with 16 mm and finish with small pipes if necessary next to the targeted plants. The drippers can be installed directly on the secondary network or of course on the tertiary network.

Not one but many networks

Too many drippers on your network will not allow you to keep a good pressure in the whole circuit. Some branches may not be supplied. It is therefore important to define several networks operating at different times from the same tank to maximize the pressure and therefore the flow.

Create separate networks for different zones, depending on whether it is a vegetable garden, a dry rock garden, a flower bed, a hedge, etc. The watering times and frequencies will not be the same in any case. 

Adapted solenoid valves

Solenoid valves are taps whose opening and closing is controlled electrically by a nearby or remote programmer. 

Most of the solenoid valves available on the automatic watering market only work from a certain water pressure, generally between 0.5 and most often 1 bar. Be careful because this information is not always available on the technical data sheets or the packaging of the products on the market. It is unlikely that you will have such a pressure or your land is very steep, so you need to find 0 bar solenoid valves, which open without or with very little pressure. This is the case of some automatic programmers like the "tap nose" for automatic watering from rainwater harvesters. Moreover, some of them propose 2 ways, that is to say the possibility to program the watering of two different circuits. Most of them work with batteries, which is good because we don't have electricity!

Programming of the automatic watering

For a bed of flowers or a vegetable garden, a watering of approximately one hour every 48 hours in summer is a base of departure to allow a watering in depth and not just wet the surface ground. Then adapt according to the needs of your plants.

Consider starting at night when the soil starts to cool down after midnight. Distinguish and adapt the programming according to the seasons, so decrease the frequency outside the summer period by passing from 48h to 72h for example.

A drip irrigation system

With a low and variable pressure according to the level in the tank, and according to the altitude of the different circuits if your garden is not flat, an adjustment of each dripper is necessary. Also adapt the flow rate of the drippers to the needs of your plants. Over time, check that each dripper is working properly, as particles can clog them or even lime deposits can block them. Make sure that the tank remains clean and free of deposits.

Although it may be tempting to use other types of sprinkler systems such as boom sprinklers, their water consumption is not at all the same and will limit the life of your water supply. So use sparingly.

Last tips...

Place taps to purge air at the end of each of your circuits.

Connect several 1000-liter tanks together to gain autonomy depending on the space available for their installation.

Test your installation for a few weeks and measure the consumption in the tank. This will allow you to estimate the available watering time in your absence or to adapt the possible watering duration.

An automatic watering system

You are tired of spending hours watering your garden with your watering can or hose. You want to install an automatic watering system to make your life easier, but you don't know which watering system to choose?

Which watering system do you need for your garden, your vegetable garden, your flower beds, your trees? Choosing the right watering system for your garden when you are not a handyman, or when you have very little knowledge is not always easy. Before buying a watering system, list your needs (plants to water, lawn, hedge ...), they will allow you to determine the system that suits you.

Do you want precise watering?

You have a vegetable garden, a hedge, fruit trees, as well as flowerbeds in your garden. Do you want precise and water-saving watering? Then drip irrigation is for you. It allows you to water the different plants in your garden or vegetable garden in an optimal way without having water running off or overdosing. The water is distributed directly to the plant and only on it.

The installation sometimes seems perilous because of the many parts to be assembled for the installation (fittings, drippers, tees, elbows, plugs, programmer ...), but the drip system does not require any particular knowledge, it is therefore accessible to everyone.

It allows you to save up to 50% compared to other watering systems, moreover it avoids the proliferation of weeds and diseases.

Do you have a large lawn area, a large garden to water?

You have a large garden with a lawn and you like your lawn to be as beautiful as a golf course? Then the underground watering system is for you. It is completely hidden in the ground, it connects to your city water or to a pump, all depends on the flow you have at the tap. In this it is important to know the pressure and flow rate of the pump you have. The installation can also be done from a well if you have one on your property, or from a stream.

Your underground watering system is linked to a programmer that allows you to regulate the frequency and duration of watering your garden. This allows you to control costs and water consumption. Your lawn is watered continuously even when you are at work or on vacation.

Automatic watering allows you to go on vacation with peace of mind, no need to ask your neighbors or family for help. You just have to define your watering hours and it will start automatically. In the summer, we advise you to water mainly in the morning when it is cool or at the end of the day once the heat of the day is over. You can also couple your installation to a rain gauge that will control the opening of the solenoid valves in case of rain, so that your garden will not be over watered and the distribution of water will be controlled.

10 tips for proper watering

Plants are 90% water. To live, they draw water from the soil through their roots and this water brings the necessary elements for growth. Like us, plants lose water through transpiration. A continuous supply of water is therefore essential to the life of plants.

Water stress (lack of water) has a direct impact on the growth of the plant, it also causes wilting and makes the plant more susceptible to diseases.

At the same time, water is a precious resource that we must save, which is possible by adopting good watering habits.

1) Prefer rainwater

Rainwater has the advantage of being economical but not only that. It is also at room temperature and does not contain chlorine unlike tap water.

If you water with tap water, remember to let it sit for a few hours in your watering can to warm up and let the chlorine evaporate.

For the sake of the planet, your plants and your wallet, think about collecting rainwater in cans or any other system adapted to your garden.

2) Water in the morning or evening

Never water in the middle of the day when it is sunny. Indeed, the heat will promote evaporation (by the soil) and transpiration (by the plants) and your water will be wasted. The combination of water and heat also risks burning your plants.

Water preferably in the morning in mid-season when the nights are still cool. If you water in the evening, any wet foliage will not have time to dry, which will encourage the appearance of diseases (fungi, etc.).

Watering in the evening is to be favored in summer when it is hot, it allows to cool the plant, to limit transpiration and losses by evaporation. The plant will also be able to take advantage of the night to hydrate itself.

3) Remove the head of your watering can

It is absolutely necessary to avoid wetting the leaves of disease-sensitive plants like curcubitaceae and tomatoes.

Therefore, you should not water in rain but rather water at the feet of the plants by using the neck of the watering can (remove the apple).

However, some vegetables like to be watered in the rain, such as cabbages and salads. The same goes for your seedlings; watering them from the neck of the watering can could break them.

4) Follow the weather

Rain is the natural watering method par excellence. But it doesn't always rain enough...

Don't water if rain is forecast for tonight, and on the contrary, water enough if your soil is already dry and the forecast is for lots of sun tomorrow.

5) Check your soil moisture

You should only water if the soil is deeply dry, not just on the surface. You can stick a stake about 30 cm into the ground and if it comes out without soil stuck to it, your soil is dry.

Another simpler and more technological solution is to use PinParco. It is a small probe to be planted in your soil that will inform you in real time of its moisture status. The data will then be displayed on your smartphone and thanks to the weather forecast, the application will also tell you the ideal time to water. 

6) Analyze your soil

The type of soil you have has a direct impact on the way you will have to water. Light sandy soils need to be watered frequently and in small quantities because they do not retain water well and dry out quickly. Heavy clay soils retain moisture better and should be watered less often and in larger quantities. Knowing your soil through a soil analysis is therefore important on this point but also to plant the right plant in the right place.

7) Study your plants

Each plant is different and has its own water needs. You must at least know the main families to know if the plant you are watering needs more or less water.

Cucurbits (zucchini, cucumbers, ...), salads, tomatoes and cabbages are for example demanding in water whereas onions, potatoes and asparagus can be watered sparingly.

Think of "designing" your garden to group plants according to their water consumption and thus facilitate your watering task.

8) Water less often but more

Generally speaking, it is better to water less often but in greater quantities. Watering every day is excessive, promotes disease and depletes the soil.

By watering less often, you will force your plants to develop deep roots, they will depend less on surface watering and will be more resistant to drought.

Seedlings, on the other hand, are very sensitive and should be watered regularly in small amounts to keep the soil moist.

9) Hoe

One hoeing is worth two waterings! Avoid letting a hard crust form on the surface of the soil under your plants, water will penetrate less easily and evaporate more quickly. So remember to loosen the soil around the plant by hoeing.

10) Mulch

Mulching prevents the soil temperature from rising and limits evaporation. Your plants will thus be able to better resist to drought.

For your mulch, you can for example use straw, RCW, flax or hemp chaff. Grass clippings that you dry first are also suitable but they decompose quickly and can create a good playground for slugs.

Mulching will also help control weeds that compete with your plants.

How to save water and limit watering?

Water is becoming scarce and consequently more expensive, so let's save it. Here are some tips to preserve it.

Limit water loss through evapotranspiration by mulching or sowing green manure (you also encourage the phenomenon of dew), these practices increase the absorption capacity of the soil during heavy rains and prevent the growth of "weeds" that compete for water with your cultivated plants.

Make sure that your soil has a good clay and humus content by making regular compost contributions, you will thus optimize its water and nutrient storage capacity. The use of a root stimulator expands the root exploration zone in the soil and allows plants to better resist periods of water stress.

Prefer underground watering, drip systems localized at the foot of the plants or microporous hoses to avoid wetting the foliage and risking cryptogamic diseases.

Choose plants adapted to the climatic conditions and in particular to the periods of drought if they are common in your region, always keep in mind not to go against nature.

Some examples of plants according to their water needs

Vegetables requiring almost no watering: garlic, onion, shallot, potato, asparagus, artichoke.

Vegetables requiring a lot of water: cucurbits, lettuce, tomatoes, cabbage.

Trees that require a lot of water: willows, alders, poplars, ash trees (they are a real pump to drain your soil; in summer, one of these trees can take several hundred liras per day).

Plants that require relatively little water: gorse, lavender, rosemary, fescue, arbutus, broom, tamarisk, boxwood, houseleek, euphorbia, sedums and, as a general rule, rockery plants, aromatic plants, ornamental grasses, conifers.

Which water to choose?

As far as possible, do not use tap water: it is cold, chlorinated and increasingly expensive!

Prefer rainwater: many models of rainwater harvesters and cisterns are available in stores. Do not hesitate to choose a large storage capacity: the investment will quickly pay for itself.

Did you know that?

1 m2 of roof space can recover about 600 liters of water in one year (depending on the region).