Tropf Blumat starter set (incl. 5 sensors + 5m supply tubing)

The starter set is the smallest complete Blumat installation: five sensors, five metres of supply hose, a tank fitting, an end piece and the manual. Enough to water five plants automatically and find out whether the system suits you before building further.

What happens inside the ceramic cone

The water in the cone is only for measuring. It is not the water your plant receives, and that is the most confusing point in the whole system.

The cone goes into moist soil, filled and sealed. As that soil dries it draws water out through the porous ceramic. Inside the sensor this creates negative pressure. That vacuum pulls on a membrane in the head, and that membrane normally holds the thin drip hose pinched shut. As soon as the membrane gives, it releases the hose and dripping begins.

Water spreads through the soil, reaches the cone again, the negative pressure eases and the membrane pinches the hose closed once more. The dripping stops by itself. So there is no electronics and no timer: it is a tensiometer operating a pinch valve, driven by nothing but the moisture tension in your root ball.

The preparation you must not skip

This is where new users usually come unstuck, and it takes ten minutes to do properly.

Unscrew the head and lay the ceramic sensor in water for at least fifteen minutes, so the ceramic saturates. Then screw it back together under water, up to the stop ring. That last part is not fussiness: any air left inside the cone is compressible, and a sensor with air in it no longer reads moisture tension reliably.

Water your plants thoroughly afterwards and push the cone into moist soil. A Blumat placed in dry ground starts dripping at full rate immediately and has no reference point.

Setting up: start at the last one

Begin adjusting at the last Blumat in the installation, not the first. Doing so bleeds the air out of the whole supply line as you go.

Open the adjusting screw until water runs from the drip hose, which should protrude about 8 centimetres from the Blumat. Then close slowly until just a single drop hangs there, and then a further quarter turn (two marker arrows). In wet soil it should not drip at all.

The sensor needs settling time, so the final adjustment happens the next day. Then watch how it runs for one to two weeks. Too dry? Open half to one marking, or extend the protruding hose to 9 or 10 centimetres instead of 8.

This set runs from a tank, not from a tap

The set contains a tank fitting and no pressure reducer. You fit it through the wall of a bucket, drum or butt, and gravity does the rest. The water level must stand above the sensors, half a metre minimum and preferably a metre. A bucket on the floor beside the plants will not work; on a table or cabinet it will.

The tank itself is not included. Any vessel does, provided you can drill a 12 millimetre hole in it. If you use rainwater, add a tank filter too, or the drip points will block.

Technical Specifications:

• Contents: 5 Tropf Blumat sensors, 5 m Ø8 mm supply hose, tank fitting, end piece, manual
• Operation: tensiometer with membrane pinch valve, no power
• Water supply: from a tank, by gravity
• Required head: at least 0.5 m above the sensors, 1 m recommended
• Not included: water tank, pressure reducer

Frequently asked questions

Why assemble the cone under water? To avoid trapping air; air is compressible and upsets the measurement.

Can I connect it to a tap? Not without a pressure reducer. This set is for a tank.

Why start at the last sensor? It bleeds the supply line while you adjust.

It is not dripping, is it broken? In sufficiently moist soil it should not drip. Check again after a day.

The soil looks dry. Water spreads underground; usually only the patch under the hose looks damp.