With the potential for drought looming across the country, water options and conservation efforts remain at the forefront of nursery operators’ priorities. Water is not optional, so having a good source is a top priority.
“Look at the Southeast, they don’t have any water,” said John Bartok, extension professor emeritus from
“Conservation of any resource is critical,” said Tony Avent, owner of Plant Delights Nursery in
Water supply is critical
Bartok said the standard amount of water required is usually one-third of a gallon to water a square yard of plants.
“Examine the number of gallons you need per day by how many hours you’ll water in the daytime and then you divide the total gallons you need per day by how many hours you’ll be watering. That gives you gallons per hour. Then you can divide by gallons per minute for the yield that you need to water that area in the summer. It will be a fairly large amount,” he said.
Designing a system to the amount of water available at your site is crucial, Avent said.
“You need to know how much water you have because there are certain systems you can use with capacities of water,” he said.
Groundwater vs. well water
The quality of water from a surface source is generally not as good as it is from a well or an aquifer, Bartok said.
“You have particulate matter in the water, runoff from adjacent farms and algae growth,” he said. “A lot of nurseries tend to have lot of algae because of high fertilizer levels.”
Ground sources like ponds, streams and rivers are generally less expensive to set up if there is a pond or brook on the property. If you have to build a pond, it is more expensive because of the equipment, which can be costly, and the time it takes, Bartok said.
Sometimes water is not as plentiful and pollution of the water is something to consider, he said. Nurseries are set up so that runoff from the irrigation area is recollected in ponds and reused again. That is factored into the use rates if they are able to collect and reuse that water.
One advantage to a well is that it generally provides a constant source of water, without drying in the summer like brooks and ponds tend to do.
“I like wells because you have clean water. When you’re pumping out of a pond, you have to deal with weeds and disease potential. That can be expensive to get that clean. With a well, you have clean water coming out of the ground,” Avent said.
Well water is generally cleaner. It may have some chemicals in it or particulate matter like sand or particles of sledge that require some filtration. The problem with wells is that the yield is variable.
In
“Wells are hit or miss,” he said. “You may drill a well at one location and not hit any water; but 6 feet over you might hit water. But, wells provide clean water with very few impurities. The yield is usually limited and as additional greenhouse space is added, another well may have to be drilled.”
“For us, we have a series of wells,” Avent said. “It was one of the things we did early on; tying all the wells together, so if we had a failure on one, we can backfeed until that one is fixed. It just saves having an emergency if one goes out, because that will eventually happen.”
Avent said linking the wells didn’t affect the cost of having multiple wells.
“We irrigate out of our wells and have ponds as a backup if they’re ever needed,” he said. “We grow in containers and it is very important to fit the water to the crop. If you don’t, you have a lot more rot problems. Conservation goes hand in hand with growing healthy crops and often people over-irrigate.”
For Plant Delights, growing is done only in square pots, so there is no place for water to fall in between them, maximizing irrigation efficiency.
“We grow small plants, in a standard 10 to 20 plat fitting 15 plants to a plat. We grow 18 in a square foot and lose no water. We maximize everything, especially the nonrenewable resources,” he said.
Well technology
When one of Avent’s wells collapsed six years ago, the redundancy of linking the wells was a lifesaver. But when he wanted to drill a new well, he hoped to do it near the old one. But, he didn’t want to do it blindly.
So he brought in H. Dan Harman Jr., senior hydrogeologist with Groundwater Services Inc. in
“He was able to pinpoint the aquifer, and we were able to drill back into the same aquifer by using technology from the oil and gas industry,” Avent said. “I tend to like more scientific technology.
“(Harman) was able to walks the property and use equipment to pick up the ultra-low-frequency waves on his monitor showing where the big rock cracks are. From there, he drove a rod with 5,000 volts, measured the resistance, plot the two together and gave me a chart with how much water was located at certain depths. You can give that to the driller and have more accuracy in where you drill. Lots of nurseries don’t realize this technology is available.”
With geophysical surveys it is easier to locate where the fractures are and, subsequently, where the water is, Harman said.
“It is analogous to a dentist conducting an X-ray of the teeth to find a cavity before he drills,” Harman said. “He knows which tooth to drill into. If he is says ‘I’m just going to start drilling into each tooth until I find a cavity’ you’re going to find a new dentist.”
Even though a landowner may have wells in the area, finding specific locations of where the water is can be difficult.
“There could be abundant water on one side of a road and nothing on the other,” Harman said. “The objective is to find the most favorable geological location in which to drill.”
While some people still use dousers and water witchers to locate drilling sites, Harman said the stick or wires simply respond to the naturally occurring electromagnetic energy coming from the Earth. Water, which conducts electricity, has its own electromagnetic energy field when confined in rock fractures. The water-filled fracture is electrically distinct from the surrounding non-electrical rock. This is why dowsing works.
However, in addition to water-filled fractures, mineral veins such as quartz also have their own electromagnetic properties. The dowser cannot tell the difference between the water-filled fracture and the quartz vein. This is why some dowsers fail to find water.
“I believe the modern geophysical approach gives you more information of what is underground,” he said.
Well requirements
For growers who aren’t sure where to start, Avent said state nursery associations may be a good first contact. Some extension services can work with nurseries or perhaps the state department of agriculture can advise on water availability.
Additionally, most states have a registry for wells. That information gets reported to the state department of health, which keeps a registry of location and yield, Bartok said. So, checking water laws regionally and by state is crucial when it comes to well-drilling.
“All states have some regulations or laws related to water usage that will vary between states quite significantly,” he said. “In
Often, Harman said, the state geological survey will have information on groundwater in most parts of most states, making it a good first source of information to seek. He also said most local well drillers are experienced and have knowledge of the areas in which they work. A hydrogeologist familiar with the area is also a good resource.
For more: John Bartok, jbartok@rcn.com, (860) 429-4842. Tony Avent, Plant Delights Nursery Inc.; (919) 772-4794; office@plantdelights.com; www.plantdelights.com. Groundwater Services Inc., (770) 924-3251; support@groundwaternrock.com; http://groundwaternrock.com.
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- Tonie Auer
Tonie Auer is a freelance writer in
June 2008