Run Drip Irrigation Any Time

Q. Should drip irrigation run during daylight hours or at night? I'm assuming there would be less water loss from evaporation if they run at night but that makes finding bad emitters more difficult.

You can turn on drip irrigation just about any time but running it at night is best. Running drip irrigation at night doesn't wet the leaves so disease is not a problem. There is less surface evaporation from the soil.

A. Time of day doesn’t matter if you’re using real drip emitters and not adjustable emitters that flood water on the soil surface. If there is standing water after using your drip emitters, then evaporation is a problem and it’s best if it’s done at night.

Drip irrigation like from this drip tubing releases water slowly over periods of hours so that it is less likely to puddle and run to low spots.

            Drip irrigation is designed to slowly release water in one small area so this water enters the soil and doesn’t puddle on top.  When adjustable emitters are used, the kind that can be adjusted to release more or less water, then this water may form water puddles on top of the soil.

            The key to evaporation is whether there is standing water. If it is truly drip and not adjustable drip emitters which flood the area, then evaporation is minimal.

            Always check first with local laws, regulations or policies regarding when it is lawful or advisable to irrigate.

Basin and bubbler irrigation is very efficient but, unlike the irrigation around this very large pine tree, the basin should be enlarged each year to hold more water. The basin under the tree should occupy at least about half of the area under the canopy.

            Consider applying wood chips to the soil surface instead of rock to conserve water. Wood chips on the surface of the soil where water is released will slowly “rot” wood chips and improve the soil in only a few months. This soil improvement helps water released from drip emitters to enter the soil more quickly and reduce puddling and evaporation.

Woodchips on top of desert soils and in contact with water improve these soils and help water to penetrate more deeply to the roots of plants. This improvement can happen in the first year after the surface mulch of woodchips is applied in the irrigated area.

            Free woodchips are available from the University Orchard in North Las Vegas or the Cooperative Extension office south of the airport. Call the Master Gardener helpline at 702-257-5555 to get directions where to get it.