Cut Costs with Less Heat and Water
Thanks to extensive university research, our industry continues to become more efficient in crop production.

by Michael Kovalycsik, National Sales & Marketing Director, Delta T Solutions


Moist Heat
Hydronic heating systems circulate hot water through rubber tubes installed in greenhouse bench systems. Growers can heat different crops efficiently through the use of zone heating, easily accomplished with hydronic bench heating.

As growers look for ways to cut costs using less heat and water, they increasingly look to ongoing research for more ideas. With several horticulture departments at land grant universities nationwide, all of which are dedicated to helping growers improve their growing methods, the horticulture industry continues to flourish and, despite trying times and struggling economies, become more efficient and sustainable.

Dr. Erik Runkle and his team of graduate students at Michigan State University have studied new ways to grow crops efficiently with less heat for the past six years. In a series entitled “Energy-Efficient Annuals,” published in Greenhouse Grower, the MSU team provided crop-specific information in response to growing temperatures.

“What we learned from our research, reported in the “Energy-Efficient Annuals” series, is that it is not possible to make blanket statements about growing temperatures because answers depend on the crop, time of year, greenhouse location and characteristics, desired plant quality, etc,” Runkle says. “In other words, it's very situational.”

With this knowledge, Dr. Runkle was kind enough to provide a few key points in response to our questions about ways to grow crops cooler.

Delta T Solutions (DTS): What are 5 things every grower should know about reducing temperature in the greenhouse to save on costs?
1. Crops develop in response to the average daily temperature (day+night) so a lower greenhouse temperature means crops take longer to develop and flower.
2. Lower temperatures may not actually lower energy costs. Although a cooler greenhouse temperature may reduce energy consumption for heating on a daily basis, it may actually increase energy consumption on a per crop basis since crop timing is longer at lower temperatures.
3. Perform your own analysis of the effects of temperature on crop timing using the Virtual Grower and FlowersOnTime (under the Growers Tools topic) tools.
4. Generally, crops grown at lower temperatures are of higher quality (have more and larger flowers) than when grown at high temperatures, especially for cold-tolerant crops.
5. Avoid low temperatures (e.g., <65 F) with cold-sensitive crops such vinca and celosia.

Hydronic heating
Hydronic heating is an economical, efficient energy alternative that promotes healthy plants and saves
growers money.

DTS: What are the rules of thumb for reducing temperature in the greenhouse?
1. There is no such thing as a free lunch; if you lower the average temperature, crop timing will be delayed.
2. Growers can potentially save on daily energy costs by providing a warm day and cool night temperature, although this creases a +DIF, which promotes stem elongation in most crops.
3. If crops are ready for shipping but for some reason can not be shipped, provide cool temperatures to slow down development.

DTS: What should a grower NEVER attempt to do, regarding crop temperature?
Runkle: Never go below the estimated base temperature (which usually ranges from 34-38 degrees F for cold-tolerant crops to 46-52 degrees F for cold-sensitive crops).

DTS: How important are heating/growing zones in controlling temperature in the greenhouse?
Runkle: Ideally, crops would be grown at different temperatures based on their sensitivity and responses to temperature. For example, cold-tolerant crops could be grown 10-15 degrees F lower than cold-sensitive crops.

DTS: For growers new to this concept, where do you suggest they start, to improve efficiency and reduce temperature for lower heating costs?
Runkle: Spend time using FlowersOnTime and Virtual Grower. An investment in time with these tools now can reap cost savings and improve crop scheduling in the future. Finally, here are some additional relevant articles and websites that you may wish to review:


Flood and Bench
Delta T Solutions offers automated irrigation systems for efficient, sustainable watering.

Automating irrigation is one of the best and most efficient ways of watering crops — a fact we at Delta T Solutions are happy to promote. Recent findings by a collective body of researchers has found that one of the latest innovations in irrigation automation is the use of substrate moisture sensors, which trigger irrigation. These inexpensive sensors can help conserve water, reduce pollution and improve efficiency by reducing electricity for well pumps. Researchers found that a wide variety of annual and perennial plants can be irrigated with as little as 0.3 to 1.3 gallons of water for an entire cropping cycle, when using substrate moisture sensors.

Researchers also found that substrate moisture sensors help reduce pathogens, in addition to preventing water waste and saving money through automated irrigation in your greenhouse. Although sensors are currently used in drip irrigation or capillary mat systems, they are likely to be used in other sustainable irrigation systems such as sub-irrigation, as well. Click here for the whole story.

Meanwhile, to learn more about sustainable automated irrigation systems from Delta T Solutions, including our Flood and Bench Irrigation Line, warm water irrigation systems and constant pressure irrigation systems, contact one of our representatives by calling 800-552-5058 or email:


Delta T Solutions
27711 Diaz Rd, Suite B, Temecula, CA 92590 • 800.552.5058 • 760.682.0428 (fax) •