Drip irrigation for balconies

A drip kit is the most useful thing on a balcony with more than a dozen pots. It gives each plant a measured amount of water at the same time every day, whether you are home or not, and it waters slowly enough that the mix soaks it up rather than letting it run off onto the balcony below. The parts are simple. Once you know what each one does, you can adjust it yourself and spot problems early.

How the kit fits together

It starts at the tap. A tap adapter screws or clamps onto the balcony tap, and a battery timer fits onto that; the timer opens and closes the water on a schedule. Most kits have a small filter after the timer, which stops grit blocking the drippers. From there a 16 mm main line, a black pipe, runs along the base of the wall or behind the planters. At its far end is a cap you can open.

Along the main line, thin 4 mm tubes branch off to each pot, pushed into small holes punched in the pipe. Each tube ends in a dripper held in the mix by a small stake. Drippers are rated in litres per hour, so a two-litre dripper running for ten minutes gives a pot roughly a third of a litre. Most balconies need somewhere between five and fifteen minutes a run, and the team sets that on install day.

How many drippers per pot

The rule we use is one dripper for a small pot, up to about 10 inches, and two for a large one, placed on opposite sides of the root ball so all of it gets wet. Big planters and troughs may need three or four. Plants that like to dry out, such as succulents, jade and snake plant, are better off the line entirely, or on a dripper with its own small shut-off valve. Palms, ferns and herbs benefit most.

When one plant looks too dry or too wet, change its dripper, not the timer. The timer serves the whole balcony.

Setting the timer through the year

In April and May, most balconies need one or two runs a day: early morning, and on west-facing balconies sometimes late afternoon too. In winter, one short run a day or every other day is plenty. In the monsoon, cut the run time well back once the rain sets in, or pause the timer altogether during the wettest weeks in Mumbai. In Bengaluru, halving the run time is usually right; in Delhi, adjust for July and August. Whatever the season, check the mix with a finger once a week.

Flushing, and going away for a week

Once a month, open the end cap of the main line and run the timer manually for a minute to flush out silt and algae, then close it. Clean the filter at the same time. If a dripper stops, pull it out and rinse it, or replace it; they push in and out by hand. Tap water in much of India is hard, and drippers slowly scale up over a year. If one pot starts drying out while its neighbours are fine, the dripper is the first thing to check.

Before a week away, change the batteries in the timer even if they look fine, and do a test run three days before you leave. Walk the line and check that every dripper is dripping. Group any pots that are off the line close together in the shade, water them well, and ask a neighbour or the care team to glance at the timer once midweek.