Growing Systems — Drip Systems

Drip irrigation gives a little often rather than a lot occasionally, so the substrate stays evenly moist instead of swinging between soaked and bone dry. Nearly everything on this page is Blumat, and that system is unusual for a reason you only appreciate during a power cut: there is no pump, no timer and no plug on it.

How a ceramic cone manages that

A Tropf-Blumat is a ceramic cone you fill with water and push into the substrate. As the soil around it dries, it draws moisture out through the ceramic; the suction that creates opens the valve and water flows. As it becomes moist again, it closes on its own. So the system responds to the tension the plant itself creates, rather than to a clock. The weather, the pot size and the growth stage set the watering rhythm without you adjusting anything.

Laying out a line

You build it from two diameters. The 8 mm supply hose is the main line, in white or black, by the metre or on 10, 25, 50 and 100 metre rolls. From it you branch with a T-piece into 3 mm drip hose running to the sensors. Working from your own tank, the feed-through passes through the wall; working off a tap, a 1 bar pressure reducer belongs in the line, because mains pressure is far too high. The individual parts are under System Parts.

Starting without buying everything at once

The trial set with five sensors and five metres of hose is meant for trying the system out small, and that is wiser than it sounds: where you place the cone determines how it behaves, and you learn that faster on five plants than on fifty. After that there are sets of 3 and 10 metres, the maxi set for up to twelve large pots from 30 cm across, and a box of 50 sensors. For houseplants there is a separate cone with a suction hose, and two bottle adapters delivering 0.2 or 0.3 litres a day.

Where it works less well

The cone reads the tension around it and is therefore most predictable in a medium that holds moisture, such as soil and coco. In Clay Pebbles most of the water runs straight through and a system that keeps dosing suits better. For watering from below there is the separate drainage hose.

Frequently asked questions

How deep do I set the sensor?
So the cone sits fully in the substrate and reads at root depth, not just under the surface where things always dry first. Fill it with water before placing it, or it reads nothing at all.

Does the system keep running in a power cut?
Yes, no power is involved. The tank only has to stand higher than the plants, since gravity does the transport.

Why does one sensor give more than another?
Usually placement, or a height difference in the line. Get the supply level and check whether there is air in the 3 mm hose.