There is that moment in late July when you walk through the garden with a full watering can and realise this is the ninth one. Your hand is red from the handle, the bed still is not properly soaked, and you have not even looked at the pots on the terrace yet.
There is a better way, just not in the shape of one single device. Watering a home garden is a chain of parts that have to fit together: tap, coupling, hose, manifold, dripper. And the can stays right where it is, because it does things no drip system can do. One thing at a time: what suits what, how much pressure a drip line needs, why rainwater forces you to fit a filter, and what has to come out of the pipes in late autumn.
At a glance
- The can stays, even once you automate. Seedlings, freshly planted stock and pots need a measured amount of water in one specific spot.
- Drip line instead of sprinkler in the vegetable bed. Water at the root, dry leaves, less fungal pressure.
- Pressure is the most common problem. Ordinary soaker hoses want 0.5 to 1 bar, micro drip systems around 1.5 bar. Without a pressure reducer, connectors blow apart.
- Rainwater without a filter clogs the system. A fine filter of 120 mesh or better belongs upstream of the first manifold.
- In autumn the water has to come out. Trapped water that freezes will split couplings and valves.
The watering can: underrated, irreplaceable
Ten litres is the standard size across the German-speaking region, and there is a physical reason for that: ten litres of water weigh ten kilos. Buy a 14 litre can and by the third trip you will be filling it halfway. Two ten litre cans beat one big one, because you can stand both under the water butt at once. Check that the spout rises above the rim of the can, otherwise it will slop over your shoes.
The part that really matters is the rose, or more precisely: the fact that it pulls off the spout. Pushed on, it gives you a soft rain that waters seedbeds without washing the seed out of the soil. Pulled off, you get a focused stream aimed at the root collar. With tomatoes (Solanum lycopersicum) that is exactly what you want: water into the soil, not a drop on the leaf.
Everything hangs off the tap
The outdoor tap decides whether watering is a chore or something that just runs alongside everything else. A tap connector with a click system, a two way splitter on top of it, and you can run hose and drip system at the same time.
Pick one coupling system and stick with it. Click couplings look alike but do not always seat cleanly in each other. Mixed brands are the reason for those little sprays that soak your trouser legs.
A backflow preventer belongs upstream of the first coupling
A hose end lying in the bed or in the water butt will siphon dirty water back into the house plumbing if the mains pressure drops. That is why DIN EN 1717 and the German drinking water regulations require a safety device on garden taps, usually a pipe interrupter or a backflow preventer. Many newer outdoor fittings have one built in, older ones do not, in which case you screw one in for very little money. And: a rainwater pump never gets coupled to the drinking water line. Rainwater gets its own pipe and its own manifold.
Garden hose, click system, hose reel
Three things matter with a hose, and none of them is the colour. The internal diameter sets the flow rate: up to roughly 20 to 30 metres, 1/2 inch is plenty and it is the standard in a home garden. From 30 to 50 metres, on permanently laid runs, or when sprinkler and drip system are meant to run together, 3/4 inch gives you noticeably more flow. The textile reinforcement decides whether it kinks round corners. And be generous with the length, because nothing is more annoying than a hose that runs out three metres short of the last bed.
A hose reel is there to protect the material, not to make life comfortable. A hose that lies in a heap in the corner develops kinks, and sooner or later the reinforcement tears at a kink. How to spread the water once it gets there is covered in Watering the garden properly.
The first water out of the hose does not go on the plant
A dark hose that has been lying in the sun for hours holds water well over 40 degrees inside. Run the first half minute off onto the path until cool water comes through. There is a hygiene angle too: warm standing water in a hose is a breeding ground for germs. Let it run first, then spray, and keep the mist out of your face.
Soaker hose and drip line for the bed
This is where the biggest step up happens, and it is not about litres, it is about where the litres end up. A soaker hose is made of porous material, usually recycled rubber, and sweats water along its whole length. A drip line has built in emitters at fixed spacing, typically every 20 to 33 centimetres. For a vegetable bed laid out in rows it is the tidier answer, because you can line the emitters up with your planting distances. The soaker hose wins where you want an area to stay evenly moist: under a hedge, along a row of soft fruit, in a densely planted perennial border.
For plant health this is the real gain: if you water cucumbers, courgettes or squash from overhead, the leaves go into the night wet, and that is precisely what downy mildew, grey mould and blight are waiting for. On length: depending on the manufacturer and your inlet pressure the limit sits somewhere between 25 and 50 metres per run, and closer to the lower end if pressure is low or the ground rises. Feed from both ends and each side only has to supply half that length. Push a run too far and it drips hard at the front and not at all at the back.
Wet leaves in the evening feed downy mildew and blight
The spores of downy mildew on cucumber and courgette, and those of late blight on tomatoes, only germinate if the leaf stays wet for several hours. Watering overhead in the evening on a warm, still night invites both into your bed. Powdery mildew is the odd one out: it needs no free water at all, in fact free water holds it back. It turns up anyway when days are warm, nights cool and the air humid, and what helps against it is spacing and air movement through the planting, not a watering regime. Where you cannot switch systems, water early in the morning and only at the base of the plant.
Micro drip system: manifold, pressure reducer, emitters
As soon as pots, raised beds and a greenhouse join in, one continuous hose stops being enough. That is when you build a micro system: a 13 millimetre main line, 4.6 millimetre distribution tubing branching off it, individual emitters at the ends. Adjustable emitters run anywhere from 0 to 15 litres per hour depending on the model, pressure compensating ones from 1 to 8; fixed emitters come in 2, 4 or 8 litres. That is how you give the pot holding the tomato ‚Berner Rose‘ a different ration from the shallow herb trough beside it.
The component beginners leave out most often is the base unit at the tap. It brings the mains pressure down to a steady 1.5 bar and usually has a filter built in. Without that reduction, your 3 to 6 bar of mains pressure sits directly on push fit connectors that were never built for it.
The connectors are the weak point
The tubing itself lasts for years. What fails is the joints: the T piece, the elbow, the end plug. In the cold the material goes hard, in the heat it expands and slips.
Walk the whole run once after you first turn the water on, with the system under pressure. Wherever it squirts instead of dripping, push the tubing a bit further into the connector.
Measure the bed and fix the rows
Sketch out the planting rows and add 15 per cent spare for bends and the supply line. With lettuce or Chinese cabbage one run sits centrally between the rows.
Fit the base unit and filter at the tap
Tap connector first, then the base unit with pressure reducer and filter, then the supply line. With rainwater, add a fine filter on top.
Relax the main line in the warm
Roll the tubing out on a warm day and leave it in the sun for half an hour. Tubing pushed together cold pops back out of the connectors later.
Place the emitters and close the ends
Push the emitters in at the planting positions, not on an even grid. A pot of basil needs one, a big tomato pot needs two set opposite each other.
Calibrate the run time with a spade
Let the system run for twenty minutes, then push a spade in next to an emitter. It has to be moist 20 to 25 centimetres down. If it is not, double the time and check again. That number is your run time, not the one in the instructions.
Cover with mulch
Grass clippings, straw or wood chip protect against UV and keep evaporation down. More in Mulching: protecting the soil.
Rainwater: the filter is not optional
Rainwater is soft and free of lime, and it costs nothing. That is exactly why most people end up using it for irrigation, and exactly why most drip systems clog: strands of algae, pollen residue and fine grit off the roof all come out of the butt with it. Butt water does not belong on the leaf though, certainly not on lettuce, herbs and anything else that goes on the plate raw. Water at the base, and rinse the harvest with tap water. The butt needs a lid anyway, against algae, against mosquitoes, and because small children and hedgehogs drown in open ones.
A mesh filter between pump and manifold catches all of it. The mesh should be no coarser than 120 mesh, which is about 130 micrometres; with fine emitters running 0.5 to 2 litres per hour you are better served by 155 mesh. Rinse the cartridge out monthly, and every two weeks through a hot August.
The second issue is pressure. Gravity out of a butt gives you around 0.1 bar per metre of height difference, and no normal drip system will run on that. Two routes get you past it. Either you buy a soaker hose explicitly built to run unpressurised off a butt, which exists as its own type alongside the 0.5 to 1 bar models. Then you stand the butt on a plinth, at least 50 centimetres of outlet height above bed level, lay the run without any uphill sections and keep it to roughly 10 to 25 metres, depending on what the manufacturer says. Or you fit a small submersible pump, in which case pressure works exactly as it does off the mains: base unit with pressure reducer in front of it. How to collect enough of the stuff in the first place is covered in Collecting rainwater: butt or cistern.
Build a flush point into the end of each run
Fit a small shut off valve at the end of every drip run instead of a fixed plug. Once a month, open it, flush for thirty seconds at full flow, close it again. The silt goes out before it can block the last few emitters.
Timer and soil moisture sensor
A watering timer on the tap turns a drip system into an installation that keeps running while you are sat in the office. The mechanical countdown timer you wind up by hand, it shuts off after the set time and needs no battery to do it. The electronic kind handles start time, duration and days of the week. One rule when programming: early and infrequent. A start between 4 and 6 in the morning puts the water down in the coolest hour of the day.
Work out the duration in litres, not in minutes. With no rain, a vegetable bed wants roughly 15 to 25 litres per square metre per week, split across one or two soakings that really get down there. How long that takes depends on your emitters: target amount divided by emitter output times the number of emitters per square metre. One run per row with 2 litre emitters every 30 centimetres and 60 centimetres between rows adds up to around 11 litres per square metre per hour, so for 15 litres the timer runs a good hour and a half. Pots are the exception, they need water daily in high summer and twice a day when it is hot.
The soil moisture sensor sits about 15 centimetres deep in the bed and interrupts watering when the soil is wet anyway. Put it in the driest spot, not the wettest, and calibrate it once by hand: spade in, look at the soil, compare the reading.
What makes sense when
- Balcony and terrace with pots
Can plus a micro drip system with adjustable emitters and an electronic timer. Pots dry out faster than any bed.
- Vegetable bed in rows
Drip line with fixed emitter spacing, laid under mulch, pressure reducer at the tap. The can stays parked beside it for anything freshly planted.
- Fruit hedge and perennial border
Soaker hose snaked through the area. One run of 25 to 50 metres depending on pressure, otherwise split it.
- Greenhouse
Drip system plus soil moisture sensor, because no rain helps you under glass and demand can double from one kind of weather to the next.
- A fortnight away
Timer plus drip system plus one person who looks in after the first week. Details in Watering while you are on holiday.
What decides whether your plants have had enough is not the equipment, it is how deep the water gets into the soil. Anything that only wets the top five centimetres trains shallow roots.
Gartenkern editorial team
Making it winter proof and draining it down
Across most of the German-speaking region, late October to mid November · CW 44 to 46 is the point at which the water has to come out of everything. Higher up and near the Alps you are two to four weeks earlier, and at the latest once two nights below zero are forecast back to back. Do not wait for the first frost warning, because by then the evenings are already cold enough to freeze the water left in a thin distribution tube.
The order never changes: shut the stopcock inside the house, open the outdoor tap and leave it open so that expanding ice has somewhere to go. Then open the drain screw on the stopcock, bucket underneath, and let the stretch between them run empty. It is precisely that column of water between the inner valve and the tap that otherwise freezes and splits the pipe. Both stay open over winter. Frost proof outdoor fittings drain themselves, but they still want the hose uncoupled. Take the timer off, remove the battery, keep it dry. Unscrew the filter, rinse the cartridge, store it open. Uncouple the hose, let it drain and store it somewhere frost free.
Drip lines and soaker hoses can stay in the bed, but opening the ends is not enough on its own: water sits in every dip in the ground. Flush the run through at full flow first, then let it drain downhill, or lift it and pull the water through. Pressure compensating emitters, manifolds, valves and anything with a thread all come off, and soaker hoses made of recycled rubber are best rolled up and stored frost free if you are unsure. What to do with the rest of the tools is covered in Putting garden tools away for winter.
Cans upside down, not upright
A can that stands upright under the porch roof all winter collects rain and meltwater. On a zinc can that splits the seam, on a plastic one the base bursts.
The order to buy things in
Buy it all at once and you will buy too much of it, and mostly the wrong things. Start with a can and a decent hose on a click system. In the second year add a drip line for whichever bed has cost you the most time. Only once that runs reliably is the timer worth it. Planning a complete system is covered in Planning a drip irrigation system.
What makes the kit valuable is not the catalogue, it is what you remember. Which year the kohlrabi went woody because you did not water for ten days. When the drip line clogged for the first time. Whether the strawberries were sweeter the year you ran the soaker hose. Note it in the garden journal, along with the date you drained everything down in autumn. After three years you can read off what your garden needs instead of guessing.
Common questions about watering kit
How much pressure does a drip line need?
Considerably less than comes out of the mains. Soaker hoses work best at around 0.5 to 1 bar and micro drip systems at about 1.5 bar, while the mains usually delivers 3 to 6 bar. That is why a pressure reducer belongs directly behind the tap. Outlets that squirt rather than drip are telling you the pressure is too high.
Can I run drip irrigation off rainwater from the butt?
Yes, but only with a filter and usually with a pump. Standing water carries algae residue, pollen and fine grit that block the emitters. A mesh filter of at least 120 mesh belongs upstream of the first manifold, and you rinse the cartridge monthly. At one metre of height difference the butt only delivers around 0.1 bar. Without a pump that leaves you only a soaker hose built for unpressurised butt operation, and even that wants the butt at least 50 centimetres above bed level and a run of no more than 10 to 25 metres.
Should the drip line go over or under the mulch?
Under the mulch. The layer protects against UV, which makes the material brittle, and keeps the water in the soil. Lay the line first, do a test run, check every joint, and only then cover it up. Do not bury it completely, or you will never find a blocked spot again.
When do I need to make the irrigation winter proof?
Between late October and mid November · CW 44 to 46, before the nights drop below zero for good, and two to four weeks earlier near the Alps and in higher country. Stopcock in the house closed, outdoor tap left open, drain screw on the valve opened and the run emptied, hoses drained and stored frost free, timer removed and battery taken out. Drip lines can stay in the bed if you flush them first, let them drain and take off everything with a thread on it.
How often should the timer run?
Rarely and long rather than often and briefly, and you work it out in litres, not minutes. With no rain, an outdoor vegetable bed wants roughly 15 to 25 litres per square metre per week, split across one or two soakings that really penetrate. How long the timer has to run for that depends on emitter output: at around 11 litres per square metre per hour you are looking at a good hour and a half per soaking. Check it once with a spade, it has to be moist 20 to 25 centimetres down. Pots are the exception, they need water daily in high summer.
Do I really need a soil moisture sensor?
Not as your first purchase. It pays off once drip system and timer already run reliably and you want to protect the automation against rainy days. Then it saves you real waterings and keeps the raised bed from getting waterlogged.
Sources and further reading
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