Tropf Blumat set 3 meter

The 3 metre set serves twelve plants or roughly three metres of balcony trough. It holds twelve sensors, seven metres of supply hose, a tank fitting, an elbow, a T-piece and an end piece, and it runs from a tank, not from a tap.

How many sensors per trough or pot

This is where people most often miscalculate, because you count root balls rather than plants. Blumat's rules of thumb:

• Four sensors per 1 metre balcony trough
• Three sensors per 80 centimetre trough
• One sensor per individual pot up to around Ø25 centimetres

The reason lies in how the sensor measures: it reads moisture tension in the patch of soil it sits in, and nothing else. To the system a long trough is therefore not one plant but a row of separate measuring points, because the substrate at one end knows nothing about the other. Twelve sensors cover three metres of trough, or twelve separate pots, or a mixture.

Where the drip point goes

This is the adjustment almost nobody thinks about, and it works more powerfully than the screw.

The drip hose protrudes about 8 centimetres from the sensor, and that distance decides how quickly the water you deliver finds its way back to the cone. With the drip point close to the sensor, the cone notices the water quickly, the negative pressure eases quickly and the membrane closes sooner: the plant gets less. Move it further away, to 9 or 10 centimetres, and the water takes longer to reach the cone, so the Blumat gives more.

In a trough, aim the drip points between the plants so water spreads both ways rather than running past one root ball. And do not be misled by a dry-looking surface: water travels underground, and usually only the spot beneath the hose looks damp.

What is in the set, and what is not

Twelve sensors with hose and T-pieces, seven metres of supply hose, the tank fitting, an elbow, a T-piece and an end piece. Seven metres looks generous for three metres of trough and is not: the line runs from the tank to the first trough, then past every measuring point, and each point takes length in its branch.

The tank is not included. One is needed, and the water level must stand at least half a metre above the sensors, preferably a metre.

Technical Specifications:

• Serves: 12 plants or around 3 metres of balcony trough
• Contents: 12 sensors, 7 m Ø8 mm supply hose, tank fitting, elbow, T-piece, Ø3-8 mm end piece
• Rule of thumb: 4 sensors per metre of trough, 1 per pot up to Ø25 cm
• Drip distance: around 8 cm overhang; more gives wetter
• Water supply: from a tank, by gravity

Frequently asked questions

How much trough do twelve sensors cover? Around three metres, at four per metre.

Why not one sensor per trough? A sensor reads only the root ball it sits in; it never notices the rest of the trough.

My plant is getting too little water. Open the screw half a marking, or extend the protruding hose to 9 or 10 cm.

Is a pressure reducer included? No. This set runs from a tank. For a tap connection, see the 10 metre set.

Can I connect larger pots? From Ø30 cm and 25 cm deep, use Maxi sensors.