Tina Ellis and James Kurtz moved to Ashland from San Diego a year and a half ago. In Southern California, they got used to having a year-round vegetable garden and weren't used to the kind of snap frosts of their first year here that wiped out plantings.
They decided a greenhouse was the answer, but they wanted a watering system that would allow them to take off for a few weeks and not have to worry about coming back to dead plants.
Zack Williams of Regenesis Ecological Design in Ashland gave them a state-of-the-art watering system for their 20-by-20-foot greenhouse.
Instead of a timer, the system uses an advanced, "smart" controller and sensors that determine the amount of water in the soil available to the plants. The controller can water up to 200 zones, though only four zones are needed in the greenhouse.
"We put in a sensor that knows when the system needs to be replenished," says Williams. He explains that this is an improvement on a timer system because if the weather suddenly changes, if there is a sudden heat wave, for instance, the sensor will tell the system to increase the watering, something a simple timer can't do.
The advanced Solar Sync sensor also knows it shouldn't water if the temperature has fallen close to freezing or if it rains, and it will wait for the weather to change. It gathers both temperature and sun-ray data to calculate evapotranspiration and determine the plants' water needs. This is not a standard application for a home greenhouse but is being beta tested for residential use in the Ellis-Kurtz greenhouse.
Plants in the greenhouse are watered by drip emitters, spray emitters or foggers.
"This is a cold house," says Ellis, explaining that a backup heater keeps the greenhouse from freezing but doesn't go on otherwise. It keeps their four, dwarf, citrus trees alive, and they are able to grow lettuces, garlic, carrots, parsnips, spinach and peas during the winter. Fifty-gallon drums of water hold up the plant shelves and serve as passive thermal mass, storing heat from the sun during the day and releasing it into the greenhouse at night.
The greenhouse is a standard, aluminum-frame model with double-wall, polycarbonate sides.
"Dumb systems overwater everything to make sure they don't underwater," says Williams. "The smart system uses only as much water as the plants actually need."
The smart system uses approximately 40 percent less water than a system that relies only on a timer. It also is more cost-effective because fewer plants die and have to be replaced, and fruit and vegetable plants watered correctly have higher yields.
"I just love having the greenhouse and being able to grow things in it year-round," says Ellis. "It's just a passion for me."