Greenhouse Watering: How To Do It

Last updated on October 23rd, 2023 at 09:04 pm

Greenhouse Watering: How To Do It

In addition to light, plants need water to grow and thrive. Especially in larger greenhouses and on large growing areas, the plants should be watered daily, especially when the outside temperatures are warm. If you don’t want to water your greenhouse plants by hand every day or don’t have the time, you need an alternative – irrigation systems can be a good and practical option here. Learn here how to water properly in the greenhouse itself and what options there are for watering.

Proper watering
To begin, we’ll explain all the basics about watering your plants in a short digression.

Greenhouse Watering: How To Do It

The perfect water:
In many regions, tap water is rather chalky and thus too hard for some plants. It is therefore advisable to use rainwater for irrigation whenever possible – for example, you can connect the garden irrigation to a rainwater cistern or rain barrel.

The right amount of water:
As a general rule, don’t water until there is a need. Before watering, check the soil to see if it is still moist or already dry. Different plants also have different water needs (more on this below).

The perfect water
When watering, the following applies: For plants that have been standing for a long time, the soil should be soaked to a depth of about 20 cm. Newly planted plants need more water and should be watered daily as needed.

The closer you water to the ground, the less water is lost. Water that does not seep into the soil evaporates directly – especially on very warm days.
The right time:
It’s best to water early in the morning. Then the soil is coolest and the water has the chance to penetrate deep into the soil, to supply the roots sufficiently and not to evaporate again immediately. Especially in the warm summer months, you should not water the plants in the evening, because during the day the soil warms up. If you now water the plant, a large part of the liquid evaporates and a moist, warm environment is created. This attracts mainly slugs and other vermin and damages the grown fruits and vegetables.

As a rule, it is recommended to water the plants in the greenhouse at least once a week. In hot summer months, it is a good idea to water your plants two to three times a week, depending on the plant species and individual water needs. When watering, be sure to always water crops at the root and keep leaves from getting wet to prevent disease. The use of garden hoses with a sprinkler attachment is therefore not recommended.

Watering systems
Depending on the size and growing area of your greenhouse, watering your plants every day can certainly take a lot of effort – especially if you don’t water your plants with a garden hose, but instead fill individual watering cans. An automatic greenhouse watering system can be a huge labor-saver in this regard, whether for everyday use or when you’re on vacation. As a rule, automatic solutions are also more water-efficient than watering by hand. But which type of irrigation is right for your garden?

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Planning your garden irrigation
Before you start planning your automatic garden watering system in detail, you should clarify the following questions:

Where are your water connections located?
How many square meters of area do you want to irrigate?
Which plants have which water requirements?
Where is no watering necessary?
Which system is the right one?
How many sprinklers, sprinklers and drip systems do you need?
To be clear about the exact planning of the system, it can also help to make a small sketch on which all plants, water connections and devices are drawn.

Automatic watering systems

Automatic greenhouse watering / Automatische Gewächshausbewässerung by  rkemper | Download free STL model | PrusaPrinters

Automatic watering systems can be a tremendous relief in the daily watering of your plants. There are different irrigation systems. So it is basically helpful to familiarize yourself with the exact functioning and basic principle of an automatic watering system: A pressure reducer is connected to the faucet, because some lines such as bead hoses do not tolerate high water pressure. From the main hose (laying pipe), small hoses (distribution pipes) with sprinklers or drippers then lead directly to the individual plants in the garden and greenhouse. Connectors create branches that allow individual paths. Depending on the setting, the same amount of water comes out of all openings or they can be regulated individually. You can also install this system underground with special drip pipes. Once everything is installed, all you have to do is turn the faucet on and off to automatically water your plants.

You can also install an irrigation computer between the faucet and the supply line. You can program this individually and thus determine when and how long the water flows. The watering computer is available either battery-operated or solar-powered. Alternatively, a simple timer can be interposed. With so-called admixing devices, you can add additional liquid fertilizer to the watering water and thus optimally supply your plants.

Smart garden watering via app is also possible. In this case, individual watering zones and times can be defined and specific elements of the watering system can be controlled. Such smart garden watering systems are often equipped with additional sensors that, for example, keep a close eye on the water requirements of the plants and trigger automatic watering as soon as the soil is too dry. Such a smart system is particularly suitable for watering during longer periods of absence, such as a trip.

Drip irrigation systems

Drip irrigation is a very economical irrigation method and ideal for targeted watering of individual plants. Such a system is particularly suitable for smaller areas. It can be installed above or below ground. For this, hose or pipe lines must be laid, which makes the installation somewhat more complex. If individual drippers are used, you can adjust the flow rate of water per hour. In this way, each plant is supplied in a very targeted and individual way.

The principle of drip irrigation is simple:
The water is fed directly to the root area of the plant via the laid pipes and the installed drippers. Depending on the water requirements of your plants, the dripper automatically regulates the water supply. Fertilizer can also be delivered to the plants in a very targeted manner.

Continuous water supplyElaborate laying of the irrigation system
No waste of waterBlockages can severely impair the functioning
Leaves of the plants are not wetted with waterSurface should be as horizontal as possible (due to low operating pressure)

Fog nozzles

Micro-irrigation with fog nozzles distributes water evenly throughout the greenhouse. As the name suggests, this creates a fine mist of water. On the one hand, this sprinkles the plants from above with the finest water particles and wets them. On the other hand, the gentle mist ensures high humidity in the greenhouse and ideal growing conditions for your plants.

For micro-irrigation, a hose system is installed in the greenhouse in such a way that the small rain droplets rain down on the plants from the roof surfaces. Unlike watering from above or an actual rain, the water mist here is so fine that the entire plant is wetted with water. At the same time, the tiny drops lower the air temperature. Such mist nozzles are especially suitable for watering young plants and rooting tables.

As an alternative to mounting them on the ceiling of the greenhouse, the hoses can also be laid between the plants. With special systems, it is possible to place the nozzles specifically between the plants and provide a targeted mist there.

Uniform water mistNot suitable for all plant species
Ideal for seedlingsDo not water the plants directly at the root
Creates high humidity
Lowers the air temperature

Solar powered irrigation pumps

Solar-powered irrigation pumps are ideal for any greenhouse that doesn’t have its own electrical hookup. Compared to mains-powered pumps, there are some differences that you should consider before purchasing:

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A solar-powered rain barrel pump (as available in conventional stores) and its comparatively small solar cell and battery do not achieve the same power output as a classic, mains-powered pump does. On the other hand, a solar-powered irrigation pump is sustainable and ecological – you simply let the sun generate the energy for the water pump.

To take full advantage of sustainable solar energy, it may be worthwhile to put in a little extra effort and install your own small solar system. This way, you can run the pump absolutely off the grid and use the energy for other devices as well. Be sure to seek professional advice on setting up a solar system and get comprehensive advice on the subject.

As an alternative to solar operation, there are also mobile batteries and gasoline-powered electricity generators that can be used to drive irrigation pumps. However, these alternatives are not very environmentally friendly because they use non-regenerative raw materials – if possible, they should only be used in exceptional cases.

Rain barrel pumpSustainable & ecologicalRelatively small solar cell & battery
Mains-independentLower power than a mains powered pump
Small solar systemMains-independentMore effort during installation
Energy can be used for other devices
Sustainable & ecological
Mobile batteryComparatively high performanceLittle environmentally friendly
Gasoline powered generatorComparatively high performanceLittle environmentally friendly

Watering according to plant type
Different plant species have very different needs when it comes to watering. Some, for example, need a lot of water, others should be watered rather infrequently, and still others also require additional support from special fertilizers.

Basically, fruits and vegetables, as the majority of them are grown in greenhouses, can be divided according to location and care requirements as follows:

Strong eaterTomatoes, cucumbers, peppers, zucchini, squash, potatoes, leeks, artichokes, cabbage, melon, rhubarb, many types of beets.Heavy growers Tomatoes, cucumbers, peppers, zucchini, squash, potatoes, leeks, artichokes, cabbage, melon, rhubarb, many types of beets Heavy growers extract many nutrients from the soil during the growth phase. Therefore, the bed should be prepared particularly conscientiously before planting to provide the plants with additional nitrogen-rich fertilizer (such as compost and manure). To prevent so-called soil fatigue, a so-called crop rotation should be carried out after two to four seasons. This means not planting members of the same plant family one after the other in the same bed, but switching to medium or weak growers. However, strong growers not only have a high demand for nutrients, but also need to be supplied with plenty of water. Tomatoes, for example, need around 500 ml of water a day, and as much as 800 ml during the flowering period.
Medium eaterCarrots, lettuce, onions, beet, beans, cabbage, garlic, spinach, kohlrabiMedium growers only need additional fertilization during the main growth phase. Compost is quite sufficient for this purpose. Medium growers also have a moderate water requirement and it is sufficient to keep the soil slightly moist.
Weak growersLegumes, peas, radishes, lamb’s lettuce, cress, herbs, strawberriesLow-growers are very easy to care for and are content with little water; too much water can actually be rather detrimental to some herbs such as thyme. In addition, weak growers do not require additional fertilizer and are content with nutrient residues in the soil left over from previous plants.


Manual watering with a watering can and muscle power can become a burden in the long run. Especially if you have a large greenhouse and grow several different types of fruit and vegetables with different needs and water requirements, investing in an automatic watering system can be worthwhile. The main advantage of such automatic systems is the high degree of customization: each plant is supplied with exactly the amount of water it needs. With the help of programmable watering systems and apps, plants can also be optimally cared for during absences and vacations. In addition to ready-made kits from the trade, do-it-yourself solutions are also available. With a little dexterity, costs can be saved.


  • James Jones

    Meet James Jones, a passionate gardening writer whose words bloom with the wisdom of an experienced horticulturist. With a deep-rooted love for all things green, James has dedicated his life to sharing the art and science of gardening with the world. James's words have found their way into countless publications, and his gardening insights have inspired a new generation of green thumbs. His commitment to sustainability and environmental stewardship shines through in every article he crafts. Jones James

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