It is a warm afternoon in late April, you come home from work, and the first thing you do in the garden is fill the watering can. Back and forth, twenty minutes long. And the next day again. Drip irrigation takes exactly that chore off your hands: a thin hose lies in the bed, releases water slowly to the roots, and a small timer at the tap handles the turning-on for you. The best time to plan and build it is now · CW 15 to 20, before the plants grow tall and the rows close over on you.
Let's go through this calmly. You don't need an engineering degree or an expensive system. You need a handful of parts that fit together, and an understanding of why each one matters. One of them in particular tends to get forgotten, and without that part the whole system won't survive a summer.
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- Drip irrigation saves up to 50 percent water compared to watering with a can, because nothing evaporates and nothing lands beside the plant.
- The order at the tap is fixed: first the pressure reducer, then the filter, then the timer, then the supply hose.
- The pressure reducer is the most commonly forgotten part. Without it, emitters and connectors burst.
- Plan and build now · CW 15 to 20, while the beds are still easy to reach.
- Water rarely and deeply rather than often and briefly. That pulls the roots down.
Why drip irrigation pays off
When you water from above, a good part of the water lands on the leaves and on the path. It evaporates before it arrives, or it encourages fungi on the damp foliage. A drip hose lays the water directly onto the soil beside the plant. From there it seeps slowly to the roots, deep rather than wide. That is exactly what you want: deep roots make your plants robust against drought, because they draw water from deeper layers.
On top of that comes regularity. Plants don't like swings between bone-dry and drowned. A calm, even supply keeps the soil moisture constant, and you taste that later in tomatoes that don't split and in lettuce that doesn't turn bitter. And quite incidentally, you are no longer chained to the garden.
Drip irrigation is no substitute for paying attention. It handles the routine, but the control stays with you. Once a week, push your finger two finger-joints deep into the soil. If it feels moist down there, the amount is right. If it's dusty dry, turn up the run time.
The parts at a glance
A drip system is a chain. From the tap to the last emitter, one part connects into the next. Here are the links in exactly the order the water passes through them.
- Tap connectorThe fitting onto the water tap or the rain barrel. Watch the thread: outdoor taps are usually 3/4 inch, some 1 inch. An adapter costs little and saves trouble.
- Pressure reducerReduces the mains pressure to the 1 to 1.5 bar a drip system can handle. The most commonly forgotten part. More on that shortly.
- FilterA fine mesh holds back sand and suspended particles that would otherwise clog the tiny emitter openings. With rain water from the barrel it is mandatory.
- TimerThe watering computer at the tap. It opens and closes the water at set times, even when you're not there.
- Supply hoseThe thick main hose, usually 13 or 16 millimetres, that carries the water from the tap to the beds. Nothing drips out here yet.
- Drip hose and emittersThe thin hose with the emitters that goes into the bed. Either with emitters built in at 30-centimetre intervals, or with individual emitters you place yourself.
- End capThe closure at the hose end. Removable for flushing, so you can wash the dirt out once a year.
The pressure reducer: the forgotten part
When a drip system starts spitting after two weeks, when connectors pop out of the hose and emitters blow off, then in nine out of ten cases the pressure reducer is missing. Mains water quickly delivers 3 to 4 bar, sometimes more. A drip system is built for 1 to 1.5 bar. The difference sounds small, but it isn't: the high pressure forces the push-fit joints apart and widens the fine emitter channels until they run unevenly.
The pressure reducer is a small, unassuming part costing a few euros that goes directly behind the tap. It is not an option but the backbone of the system. Buy it together with the rest, not as a retrofit once something has already broken.
At the rain barrel there is far less pressure than at the mains, often only 0.1 to 0.2 bar from a metre of height. There you need no pressure reducer, but you do need free-flowing, low-pressure emitters that run even at low pressure. When buying, look for the label for gravity operation or low pressure.
This is what the whole exercise is about: a single emitter releases its water drop by drop, not in a gush. The soil absorbs it, instead of it running off at the surface. A common emitter delivers 2 to 4 litres per hour. Over an hour of run time, that adds up to a decent, deeply seeping amount per plant.
Plan step by step
Before you buy anything, go into the bed with a folding rule. A system that is thought through on paper saves you expensive wrong purchases and hoses that are too short.
Measure the beds
Measure the length of each row and the paths between them. Note how many metres of drip hose you need and how much supply hose for the run from tap to first bed. Be generous with the supply hose; corners and detours cost more than you'd think.Estimate the water demand
Count your plants and sort them roughly: heavy feeders like tomato, cucumber and squash want a lot, herbs and onions little. One emitter per single plant; for long rows, a drip hose with emitters every 30 centimetres.Assemble the parts
Fix the chain: tap connector, pressure reducer, filter, timer, supply hose, drip hose, connectors, T-pieces, elbows, end caps. Buy a single brand's system, then the fittings match one another.Lay it out dry
Roll the hoses out in the bed on a warm day and let them lie in the sun for an hour. Warm material is soft and slides easily onto the connectors. Cold hose is stubborn and tears more easily.Connect and flush
Put the chain together at the tap, but leave the end caps open for now. Turn the water on and flush the line for a minute so no drilling swarf stays in the hose. Then close the end caps.Test run and fine-tune
Let the system run for an hour and walk the row. Does every emitter run? Are there puddles or dry spots? Move emitters where a plant comes up short, and plug unused holes with blind stoppers.
Setting the timer right
The timer at the tap is what turns watering into a watering system. You set two values: when it runs and for how long.
The best time is early morning, roughly between 4 and 7 a.m. Then the soil is cool, the water seeps in before the sun evaporates it, and the plants head into the hot day strengthened. Evening works too, but has the drawback that damp foliage stays wet through the night, and slugs rejoice.
For the duration the rule is: rarely and long rather than often and short. A brief daily sip only moistens the top layer, and the roots stay lazy at the surface. Better to run every two to three days for 45 to 60 minutes. The water penetrates deep, the roots follow downward, and your plants survive even the occasional forgotten day.
Many watering computers have a rain-sensor input or a pause button. Use it. After a heavy soaking rain, the bed needs no extra round for two days. Whoever waters on stubbornly drowns the roots and wastes water.
Rain water instead of tap water
A drip system runs most beautifully from the rain barrel or cistern. Rain water is lime-free, at ambient temperature, and costs nothing. Two things to bear in mind: the pressure from the barrel is low, so you need low-pressure emitters or a small pump. And a filter is mandatory at the barrel, because leaves and algae would otherwise clog the emitters. How to collect enough of it to carry the system through summer is in Collecting rain water with a barrel and cistern.
When you go on holiday
A drip system with a timer is half the battle for a carefree holiday. But don't rely on it blindly: test it over several days at least a week before you leave, so you can see whether every corner really gets water. Change the timer's battery beforehand, and have someone check in every few days. The complete plan for being away is at Holiday watering in the garden.
Care through the year
A drip system is low-maintenance, but not maintenance-free. Twice a year, in spring at set-up and in summer after the first heat wave, take off the end caps and flush the hoses through. Clean the filter as soon as the pressure noticeably drops.
Before the first frost, the water has to come out. Take off the timer, the pressure reducer and the filter and store them frost-free in the cellar or shed. Open the end caps and let the hoses drain. Frozen residual water splits connectors and fine channels. It's no drama, just a fixed date in October · CW 40 to 43.
Common mistakes and how to avoid them
The classic is the missing pressure reducer, which we've already covered. Almost as common: too many emitters on too thin a line. If no water reaches the end of the row, the hose is overloaded. Split long runs into two circuits or take a thicker supply hose. The third mistake is the forgotten filter at the rain barrel, the fourth the daily short watering that only wets the surface. All four are easy to avoid if you plan the system through once, calmly.
And remember the chain at the tap, then hardly anything can go wrong: tap, pressure reducer, filter, timer, supply hose, drip hose, end cap. In this order you protect the delicate emitters from pressure and dirt. The best moment to start is now · CW 15 to 20, while the beds lie open.
Water that runs off at the surface never reached the garden. What counts is the drop that arrives at the root.
Old gardener's rule
Häufige Fragen
How much water does a drip emitter use per hour?
A common emitter delivers 2 to 4 litres per hour, adjustable models between 0 and about 8 litres. For a single tomato plant in the heat, roughly one to two litres per day is enough, which is about 30 to 60 minutes of run time with a standard emitter. In the first week, check with your finger in the soil whether the amount fits, and adjust the run time accordingly.
Do I really need a pressure reducer for drip irrigation?
On the mains, yes, absolutely. The mains often deliver 3 to 4 bar, but a drip system is built only for 1 to 1.5 bar. Without a pressure reducer, the connectors pop out of the hose and the emitters run unevenly. Only at the rain barrel can you leave it out, because there is almost no pressure there anyway. There you need low-pressure emitters instead.
When and for how long should drip irrigation run?
Best in the early morning between 4 and 7 a.m., when the least evaporates and the foliage dries off during the day. For the duration the rule is: rarely and long rather than often and short. Run it every two to three days for 45 to 60 minutes, rather than ten minutes daily. That way the water penetrates deep and the roots grow downward, where they reach moisture even in dry spells.
Does drip irrigation work from a rain barrel too?
Yes, and it's actually the nicest solution: rain water is lime-free, at the right temperature, and costs nothing. You need two adjustments. First, low-pressure emitters, because only a little pressure comes from a barrel, or a small submersible pump. Second, a filter directly behind the barrel, because leaves and algae would otherwise clog the fine emitter openings. You don't need a pressure reducer here.
Do I have to dismantle the drip system in winter?
You can leave the hoses in the bed, but all the sensitive parts have to go before the first frost: timer, pressure reducer and filter move frost-free into the cellar or shed. Open the end caps and let the hoses drain, so no residual water freezes and splits the connectors. The best date for this is mid to late October · CW 40 to 43, before the first hard frost night arrives.
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