Frequently Asked Questions About Garden Irrigation

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Frequently asked questions about garden irrigation – expert answers from practice

Irrigating a garden may seem simple at first glance: you turn on the water, the plants drink, and that's it. In reality, behind every well-functioning garden lie several decisions that have a long-term impact on water consumption, plant health, operating costs, and the comfort of the owner. That's why we receive dozens of questions from customers every day – some of them repeat so regularly that we decided to collect the most important ones and answer them in detail, with numbers and examples from real customer projects.

If you're looking for an answer to a specific question, you can jump directly to the relevant section. If you're planning irrigation from scratch, we recommend reading the whole article – the connections are important.

Do I necessarily need an automatic system, or is a hose and a garden watering can enough?

This is one of the most common initial questions, and the answer depends on the size of the garden, your lifestyle, and how much time you want to dedicate to watering. Manual watering with a hose works reliably for small gardens up to 100–150 m², where the owner spends enough time outdoors. As soon as the garden is larger or regular gardening presence is hindered by work and travel, the manual system starts to fail precisely when it is needed most – during summer heatwaves while on vacation.

From practice: a customer with a 400 m² lawn and a garden with ornamental grasses and vegetables decided to go without automation "for just a few seasons." After two years, we installed a system because the lawn had developed a pattern of dry strips that mirrored the terrain's depressions – areas the hose simply couldn't reach evenly. The total lawn restoration cost more than a complete automatic installation.

An automatic irrigation system is worth it for gardens over 200 m², for plots with vegetables or sensitive plants, for households where the owner travels, and for all gardens with drip irrigation (because manual drip irrigation is technically almost impossible). A more detailed comparison can be found in the article How to choose the right irrigation system for your garden.

What water source is suitable for irrigation?

An irrigation system can draw water from several sources, and each has its own specifics, advantages, and limitations.

Piped water (drinking water from the public network)

The simplest source. The pressure is usually 2–5 bar, which is sufficient for most irrigation systems. The disadvantage is the cost – drinking water is more expensive than other alternatives, and for a garden of 500 m² with a daily consumption of 3–5 m³ in a hot summer, the costs quickly add up. Chlorine in drinking water can clog emitters during long-term drip irrigation, so it is advisable to install a filter.

Well or borehole

A very popular choice for family homes in the countryside. Well water is cheap (you only pay for the energy for the pump), but it requires a separate pump, pressure tank, and often also filtration. The hardness of well water varies regionally – in the Danubian Lowland, carbonate hardness values can exceed 40 °fH, which means faster clogging of nozzles and emitters. Regular water quality checks are essential. The topic of filtration and home water treatment is covered in a separate section of our store.

Rainwater (tanks and ponds)

The most ecologically valuable source. Soft rainwater is well tolerated by plants, contains no chlorine, and has a neutral pH. Pumping from a tank requires a submersible or surface pump with sufficient flow. The limiting factor is the tank volume – for a 300 m² garden with a weekly watering of 10–15 mm, you need a minimum of 3,000–4,500 liters of storage during a dry week. More on this topic can be found in the article Irrigation with recycled rainwater – what you need to know.

Surface water bodies (stream, irrigation channel)

Less common, but relevant for gardens near waterways. It requires a permit from the waterway manager and usually a coarser filtration due to silt, algae, and organic impurities.

How much water does the garden actually need?

This is a question that many underestimate – either they water too much or too little. The real water requirement depends on several factors: type of plants, soil type, climatic conditions, and the season.

Estimated values for central Slovakia in July (the hottest month):

Lawn: 25–40 mm/week (2.5–4 l/m²/day with daily irrigation)
Vegetables (tomatoes, cucumbers, peppers): 30–50 mm/week – vegetables are the most demanding
Ornamental ground covers and perennials: 15–25 mm/week after rooting, more after planting
Trees (first 2–3 years after planting): 20–40 l/tree/week depending on size
Hedge: 10–20 mm/week after rooting

Important: these values are approximate. Sandy soil holds water for a shorter time than clay soil, so it requires shorter but more frequent watering. Clay soil risks waterlogging with too long cycles. If you want precise values for your garden, consider using soil moisture sensors – today's available models can directly communicate with the control unit and automatically adjust the watering schedule.

What pressure and flow do I actually need?

Pressure and flow are the two most important parameters that determine whether the designed system will work correctly. Customers often confuse them or underestimate their impact.

Pressure is the force with which water pushes in the pipe – measured in bars (bar) or kPa. For sprinkler heads, a working pressure of 2–4 bars is usually required. Drip systems operate at a lower pressure, typically 1–2.5 bars, and require a pressure-reducing valve if the network pressure exceeds 3 bars.

Flow is the amount of water that flows through the system per unit of time – litres per minute (l/min) or m³/hour. Each sprinkler head has a minimum flow (for example, 0.8–1.2 l/min for smaller rotating heads, 3–10 l/min for turbine nozzles with a range of 8–12 m). When dimensioning the system, you must add up the flow of all heads in one zone and verify whether your water source can cover it.

Practical example: a garden of 600 m² with a lawn divided into 3 zones. Each zone has 6 rotating heads with a flow of 2.5 l/min = 15 l/min per zone = 0.9 m³/hour. A well with a pump of 1.5 m³/hour easily handles this. Problems arise when the customer wants to run all zones simultaneously – in that case, the required 2.7 m³/hour cannot be covered by a standard household pump. Solution: proper setting of the controller to sequentially alternate zones.

Detailed calculations and tables can be found in the article What pressure and flow do I need for irrigation.

What is better – drip or sprinkler irrigation?

This is perhaps the most common dilemma for gardeners, and there is no single answer – both systems have their place and real gardens often combine them.

Sprinkler irrigation

Sprinkler heads – whether fixed (pop-up) or rotating – spray water into the air and cover larger areas. They are ideal for lawns, where even coverage of the entire area is key. Disadvantages: higher pressure, water loss through evaporation (5–15 % in hot weather), sensitivity to wind (at wind speeds above 15 km/h, water distribution is uneven), and less suitable for ground cover plants, where leaf moisture can encourage mold.

Drip irrigation

Water is delivered directly to the root zone using emitters or drip lines. Minimal evaporation, water goes exactly where the plant needs it, lower pressure and consumption. Ideal for vegetable beds, perennials, shrubs, hedges, pots, and planters. Disadvantages: slower irrigation (longer time required), need for filtration, clogging of emitters (especially with hard water).

In practice, these systems are combined: the lawn gets sprinkler heads, vegetable and ornamental beds get drip lines, trees get point emitters at the base of the trunk. A detailed comparison is available in the article Drip vs. Sprinkler Irrigation – What is Better for Your Garden Type.

How to divide your garden into irrigation zones and why it is important?

Zoning is the foundation of any well-functioning system. A zone is a separate circuit with its own solenoid valve, controlled independently by the controller. Reasons to divide your garden into zones:

Different water needs: a lawn needs a different frequency and intensity of watering than vegetables or a hedge
Limited water source flow: a standard well or water connection cannot supply all parts of the garden at once
Different types of heads/emitters: sprinkler and drip systems operate at different pressures – they should not be mixed in one zone
Sun exposure: a bed next to the south wall of the house dries out faster than a shaded bed next to the fence – they must be in separate zones
Ground slope: a slope and a flat area require different watering times (a slope with sprinkler heads needs shorter and repeated watering to prevent runoff before absorption)

A typical garden of 400–700 m² at a family home has 3–6 zones. Larger gardens over 1 000 m² commonly operate with 8–12 zones. Zoning is a professional task – in the article How to Design Irrigation Zones for a Garden, Lawn, and Bed, you will find the procedure and calculation tables.

When and how long to water – in the morning, evening, at night?

The time of watering significantly affects the efficiency of the system and the health of the plants. From practice, we recommend the following rules:

Best time: early morning (5:00 – 8:00)

Morning watering has the lowest evaporation (the air is still cool and dewy), water is absorbed before the heat arrives, and leaves have time to dry during the day (which reduces the risk of mold). This is ideal for lawns, beds, and vegetables.

Acceptable: late evening (20:00 – 22:00)

Evaporation is also low, but leaves remain wet all night, which increases the risk of fungal diseases in warm and humid weather – especially on tomatoes, roses, and lawns. For drip systems, where water does not reach the leaves, evening watering is fully acceptable.

Not recommended: midday and afternoon (11:00 – 17:00)

Evaporation can reach 30–40 %, water does not have time to absorb, and wet leaves in direct sunlight risk scorching. Despite this: in the case of sudden plant stress (visible wilting), watering during the day is better than none.

How long to water?

The answer depends on the flow of the heads and the required amount of water. Approximate example: a lawn needs 30 mm/week, which is 3 l/m². Sprinkler heads with an intensity of 10 mm/hour (1 l/m²/hour) must run for 3 hours per week. These hours can be divided into 3 watering sessions of 60 minutes each, or 6 watering sessions of 30 minutes each – depending on the soil. Sandy soil better handles shorter and more frequent watering, while clay soil handles longer and less frequent watering better.

What to do if the system is not watering properly or a zone is not working?

Most irrigation system issues have trivial causes – and if the customer knows where to look, they can fix the problem themselves in 15 minutes. Most common problems:

A zone does not start: check the electrical wiring to the solenoid valve (broken cable), the solenoid itself (resilient are e.g. 24V AC solenoids, but they can burn out), the controller settings (zone turned off, wrong time), water pressure (if pressure drops below minimum, the valve will not close or open properly)
Head is not watering, but the zone is running: clogged nozzle with sand or lime deposits – disassemble and flush, or replace the nozzle
Zone is running, but water is leaking around the head: damaged pop-up head gasket or frozen and cracked head body (winterization!)
System does not shut off: stuck valve (foreign object under the seal), incorrectly set controller, solenoid valve malfunction
Low reach of the sprinkler: too low pressure (check pressure at the source), clogged nozzles, too many heads in the zone (pump flow exceeded)

A complete troubleshooting guide can be found in the article Common irrigation system faults and their repair.

How to winterize the system to prevent freezing?

Winterization is a step that customers often underestimate – until in spring we find cracked pipes or broken valves. Freezing causes water expansion, which can crack both plastic and metal fittings.

Winterization procedure (usually in October, before the first frost below −2 °C):

Turn off the controller (or switch it to winter mode).
Close the main water supply valve to the system.
Open manual air and drain valves at low points in the system.
Blow out remaining water from the pipes and heads with compressed air (compressor, pressure 2–4 bar) – each zone separately, for 2–3 minutes.
Store the controller with batteries indoors (or in the case of AC-powered units, check if it is protected from frost).
Surface drip lines can be removed and stored in a dry place or covered with mulch.

More about procedures and winterization of different types of systems can be found in the article Maintenance and winterization of an irrigation system.

Can I install an irrigation system myself, or do I need a professional?

It depends on the system's size and your technical skills. A small single-zone system with a drip hose for a vegetable bed can be installed by almost anyone – it's basically just a hose, a few emitters, and a simple timer on a tap.

Multi-zone systems with solenoid valves, buried piping, and a controller are more complex. Digging trenches for pipes (at least 30–40 cm deep, below the frost line), proper zoning, electrical installation for the controller, and system testing require at least basic practical experience. Mistakes at this stage are expensive to fix – dug-up flower beds, incorrect cable connections, or poorly sealed joints underground.

Our recommended step-by-step procedure for DIY installation can be found in the article Installation of an automatic irrigation system step by step.

How to save water when watering a garden?

Water saving is not just an ecological responsibility – in regions with droughts and rising water prices, it is also an economic issue. These measures deliver real results:

Rain sensor: a simple, cheap device (10–30 €) that pauses watering during and after rain. A customer with a rain sensor saves an average of 15–25 % of water consumption per season.
Soil moisture sensor: even more accurate – watering occurs only when the soil has actually dried below the set level.
Drip irrigation instead of sprinkler: for flower beds, you can save 30–50 % of water compared to sprinklers.
Mulching: a 5–8 cm layer of mulch (bark, compost, wood chips) reduces evaporation from the soil by 40–60 %. Direct effect on watering frequency.
Right watering time: morning watering reduces evaporation compared to midday by 25–35 %.
Rainwater harvesting: connecting a rainwater tank to the irrigation system is an investment with a payback period of 3–5 years for a larger garden.
Leak check: one clogged or damaged valve can waste 50–100 l per night. Regular visual inspection of the system is essential.

A more comprehensive guide on this topic can be found in the article How to save water when watering a garden.

What is a controller and how to choose the right one?

The controller (timer, controller unit, controller) is the brain of an automatic system. It determines which zone starts, when, and for how long. There are three main categories on the market:

Mechanical and simple digital battery-powered timers

They connect directly to the water tap. Suitable for 1 zone, without electrical installation. Price 20–60 €. Limited to a simple daily or weekly schedule.

Multi-zone AC-powered controllers

Standard type for automatic garden systems. They control 4–12 or more zones, powered from a 230V socket, with 24V AC output for solenoid valves. Programming is flexible – multiple programs, different days, sensors. Price 60–200 €.

Smart controllers with Wi-Fi and app

Modern category with internet connectivity. They allow remote control via a mobile app, automatic adjustment of irrigation according to weather forecasts (API connection to weather stations), and water consumption reporting. Price 100–350 €. For technically skilled gardeners and for gardens of higher value, this is an investment that pays off – on average 20–30 % less water consumption compared to a rigidly programmed unit.

What is the difference between a pop-up head, a rotating head, and a turbine sprinkler?

These three types of sprinkler heads differ in range, intensity of watering, and suitability for different areas:

Pop-up fixed nozzles (spray heads): they pop up 5–15 cm above the lawn when activated and spray a fixed pattern (full circle, half circle, quarter circle). Range 1.5–5 m, intensity 30–60 mm/hour. Suitable for smaller lawns up to 5 m in width, flower beds. Lower pressure (1.5–3 bar). Disadvantage: high watering intensity can cause surface runoff on compact soil – shorter and repeated cycles are needed.
Rotating pop-up heads (rotary nozzles): the nozzle rotates and applies water in slow streams. Range 3–7 m, intensity 8–15 mm/hour (2–4x lower than fixed nozzles). Suitable for all types of soil including compacted soil. More even water distribution, less runoff.
Turbine sprinklers (gear-driven rotors): greater range 8–14 m, rotate using a turbine. Ideal for large areas, golf courses, and large lawns. Higher operating pressure 2.5–4 bar, flow rate 3–10 l/min. For a typical family home, they are usually oversized.

Most frequently asked questions (FAQ)

Can I connect the irrigation system directly to the water tap without a pump?

Yes, if you have a direct connection to the water supply with a pressure of at least 2 bar and sufficient flow (depending on the number of heads in the zone). For small systems with one zone and a few sprinklers or a drip hose, it usually works without a pump in most households. If you are drawing water from a tank, well, or pond with insufficient water level, a pump is essential.

How deep should I bury the irrigation system piping?

The minimum trench depth is 30 cm, recommended is 40–50 cm. This is below the frost line in Slovak conditions (10–25 cm depending on the region and winter). In addition to frost protection, deeper burial protects the piping from a spade, lawn aerator, and garden machinery. For supply HD-PE piping (32–40 mm), a depth of at least 40 cm is recommended, for thinner distribution branches (16–25 mm) 30 cm is sufficient.

Why does my lawn stay dry in the corners, even though the system is running?

A classic problem of insufficient or incorrect coverage. Sprinkler heads must be placed so that the range of each head reaches the next head – the so-called "head-to-head coverage" principle. Corners of the lawn are critical areas: a quarter-circle nozzle placed directly in the corner is needed there. If the head is far from the corner, the corner remains dry. Solution: adding another head with a smaller range, or moving an existing head closer to the corner. Another cause may be low operating pressure, which reduces the range of the heads.

Can I use black drip hose on the surface of the garden?

Yes, drip hoses are commonly available for surface and subsurface installation. Surface hoses are easier to install and monitor, but are more sensitive to UV radiation (plastic degradation after 5–8 years) and can interfere with mowing or cultivating flower beds. Covering with mulch prolongs their life and also reduces evaporation from the soil. For permanent solutions in flower beds, it is more advantageous to hide the hoses under a layer of mulch or shallow burial (5–10 cm). Underground installations in lawns require special low-profile drip emitters and protective covering to prevent root intrusion.

What is a solenoid valve and where is it located in the system?

A solenoid (electromagnetic) valve is an automatic valve controlled by an electrical signal. The controller sends 24V AC voltage to the solenoid coil, which opens the valve and allows water to flow into the respective zone. After the cycle ends, the coil loses voltage and a spring closes the valve. Valves are usually grouped in so-called valve boxes (plastic boxes buried in the ground), from which individual branches lead to the zones. Each zone has its own valve. Solenoid valves are quite reliable, but can fail due to clogging with foreign objects, membrane wear, or coil short-circuit.

Is the investment in an automatic irrigation system financially worthwhile?

For a garden of 200 m², average water consumption is 3 m³ per week during the season (20 weeks) = 60 m³ per season. An automatic system with sensors saves real 25–40 % = 15–24 m³ per year. At a water cost of 2–4 €/m³, this is a saving of 30–96 € per year. Add to this the value of saved plants (trees, lawn, perennials), which manual watering cannot manage during a holiday. A system for a 400 m² garden costs 800–2 000 € to install – the payback period from water savings alone is 10–20 years, but the real value is in comfort, saved plants, and garden quality.

Conclusion

Irrigation is an area where the time and technical knowledge invested really pay off. A properly dimensioned and installed system works for years with little attention, saves water, protects plants, and frees the gardener from dependence on a hose and bucket. On the contrary, a system designed without thought brings constant frustration – dry corners of the lawn, clogged emitters, frozen pipes, and unnecessary costs.

If you are looking for more information on specific topics, we recommend articles in our Knowledge Center: How to choose the right irrigation system for your garden, Installation of an automatic irrigation system step by step, How to design irrigation zones for your garden, lawn and flower beds, and How to save water in garden irrigation. A complete range of irrigation equipment can be found in the Irrigation category on atria.sk.

Do you have a question about this topic?

Not sure or dealing with a specific situation in your home? Write to us – we are happy to help.