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Watering Efficiently

Originally published in the Lynn Haven Ledger
By Julie McConnell

We are still a few weeks away from the official start of summer, but the recent hot dry weather pattern has been hard on landscapes. Sun exposure in yards has increased for most properties which tends to increase water needs for plants when rainfall is inadequate. However, just adding extra days to your automated irrigation system may not be the right answer if the system is not setup for maximum efficiency.

Let’s look at a few things that need to be assessed to determine your watering efficiency.

Is your system designed to match your plant needs? Proper irrigation methods are not the same for turf, flowers, and trees. These plants have different water needs from each other, yet many people assume that irrigation that fits one type of plant fits all.

Consider turfgrass – the roots for turfgrass are in the top 4 inches of soil and the leaf surface area is limited. If you were to capture irrigation in a catch can, the ideal amount to apply to turf per cycle is ½” so that it penetrates the top 4-6 inches of sandy soil.

Tree roots occupy the top 8-12 inches of soil and the plant and surface area of leaves is exponentially larger than turf grass tissue. A newly planted tree needs 2-3 gallons of water per inch trunk diameter applied slowly to the roots.

Trying to use an automated system to water turf and trees without different zones and emitter types will result in either overwatering of turf or underwatering of the tree.

Is the water being applied uniformly? Turning on an irrigation system and only visually assessing the uniformity can be misleading. Although it may look like water is evenly reaching an entire zone, unless you measure you can’t be sure. Water pressure, wind speed, and vegetation density can all impact the ability of irrigation to reach the root zone. Rather than using only your eyes to assess your system, take the time to set out catch cans to measure output. You can purchase irrigation audit supplies or simply use a clean cat food or tuna fish can. Set 5-6 cans within a zone, run the system for 15 minutes then measure and take an average.  Adjust your time so that you are applying an average of ½-¾ inch to turfgrass areas. If you noticed areas that turn brown quickly during hot spells, make sure to measure that area and adjust as needed.

When should you water? This is really a two-part answer.

  1. The best time of day to water is 4-10 a.m. There are a few reasons why this time is ideal. The first is that winds are typically calmest at this time of day, reducing interference with the path of the water being applied. The second reason is related to disease management. Most plant diseases are caused by fungi, which need prolonged moisture to reproduce. Since we have dew most mornings if we water at the same time we are not increasing the length of time that plants stay wet. If we water in the afternoon or evening that adds hours to the amount of time foliage is wet which favors disease growth.
  2. How frequently you water is going to depend on a lot of factors including how established the root system is, soil type, and weather conditions. New plants with reduced root systems will need water more frequently for a time until they can generate robust roots. Established plants can go longer between irrigation events and can be allowed to wilt a little bit before watering. It can be hard to tell if turf is wilting, but if you look closely you can see the leaf blades start to fold in at the vein – that is an indication that it’s time to water. In general, water when rainfall is not enough to support plant growth. Because rainfall varies all over the county, place a rain gauge in your yard and look for signs from plants that they need water. Sandy soil that has very little organic matter and drains well may need to be watered more frequently than loamy or muck soil that has a greater water holding capacity. This can vary greatly throughout a landscape, so you should be watching for areas that stay moist after other areas have dried out after irrigation or rainfall. Irrigation systems may need to be adjusted to reduce or increase frequency based on soil types.

For more information on watering your Florida yard efficiently, please visit https://ffl.ifas.ufl.edu/FFL/water-efficiently.html.

An Equal Opportunity Institution. UF/IFAS Extension, University of Florida, Institute of Food and Agricultural Sciences, Nick T. Place, dean for UF/IFAS Extension. Single copies of UF/IFAS Extension publications (excluding 4-H and youth publications) are available free to Florida residents from county UF/IFAS Extension offices.

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