Understanding Plant Nutrition: Common High Media-EC Problems

Slideshow: Common High Media-EC Problems

High electrical conductivity (EC) in the growing medium makes it harder for roots to take up nutrients and water–it is like trying to grow plants in sea water and can result in “salt burn” (damage to sensitive root tips) and toxicity symptoms in foliage (Figure 1). In this article, we will discuss the causes and corrections of high media-EC.

What Causes High Media-EC?

Media-EC is a measure of the total dissolved salt concentration contained in the soil solution and is often used as a measure of the overall nutrition status of the crop. You can think of the soil nutrient level as similar to a bank account. Our account balance (media-EC) is made up of deposits and withdrawals. The deposits are made with salts contained in the irrigation water, with water-soluble fertilizer, or by slowly soluble or controlled-release nutrients. Withdrawals are made through plant uptake or leaching.

The account balance (media-EC) increases when deposits are greater than withdrawals. This can occur for a number of reasons, including too much starter fertilizer at mixing, using high fertilizer concentrations for extended periods of time when the leaching rate is low, or using a high incorporation rate of controlled-release fertilizer when the leaching rate is low. Plants also require (and “withdraw”) less fertilizer from the growing medium early in the crop when they are small, or late in the crop when growth rates decrease at flowering.

Correcting High Media-EC

The recommendations for removing fertilizer salts from the media depend on the causes of the problem. When media-EC is excessive, find out which salts are contributing to the high media-EC with a laboratory soil test. This will influence the corrective actions needed.

For example, if the salts contained in the media are made up of a balanced ratio of plant nutrients (containing nitrogen, phosphorus and potassium) and you are using a water-soluble fertilizer, then switching to clear water until the media-EC drops to a more acceptable level may be all that is necessary. In this case, you can use plant uptake to reduce the media-EC. If the media-EC is very high or the salt levels still don’t come down, apply excess water with 50 percent-plus leaching as the next option.

If the salts are made up of a balanced ratio of plant nutrients and you are using a controlled-release fertilizer, you should apply excess clear water with 50 percent-plus leaching. Controlled-release fertilizer cannot be turned off like a fertilizer injector, so if media-EC gets too high when using controlled-release fertilizer, leaching becomes the only option for salt removal. In addition, you may have to continue with higher-than-normal leaching rates to keep the salts from building up again during the crop.

If the high media-EC is from unusable ions such as sodium or chloride, then you should leach twice, once with clear water to remove the excess salt, and a second time with a complete fertilizer to reestablish adequate nutrition in the pot.

Avoiding High Media-EC

Avoiding over-fertilization is an important part of managing micronutrient concentrations. Most growers are using fertilizers (both controlled release and water soluble) that contain both macronutrients (e.g. nitrogen, phosphorus and potassium) and micronutrients (e.g. iron and manganese). As the concentration of nitrogen in the fertilizer solution increases, the concentration of all nutrients increases, including micronutrients like iron and manganese. For example, increasing the concentration of one brand of 20-10-20 from 100 ppm nitrogen to 400 ppm nitrogen will increase the concentration of iron from 0.5 ppm to 2.0 ppm in the applied solution.


The goal of any nutrition program is to supply nutrients to the root media at a similar rate to those taken up by the plant. Leaching can play a key role when the media-EC gets too high, because it can be controlled by the grower. If you find you constantly have to leach the crop because of high salts, you may need to re-evaluate the fertilizer concentration or incorporation rate being used.

Leave a Reply

More From Plant Culture...
Colorado State University 2015 Container Field Trials

November 29, 2015

2015 Colorado State University (Fort Collins, Colo.) Field Trials Results

See the 2015 field trials results (includes photo gallery) for Colorado State University in Fort Collins, Colo.

Read More
Coleus 'Colorblaze Velveteen' (2015 University of Tennessee Field Trials)

November 28, 2015

2015 University of Tennessee Gardens (Knoxville and Jackson, Tenn.) Field Trials Results

See the 2015 field trials results (includes photo gallery) for University of Tennessee Gardens in Knoxville and Jackson, Tenn.

Read More
Feature Image Cob 700 (NewLux)

November 28, 2015

16 LED Lighting Solutions For Your Greenhouse

Narrowing in on the right LED lighting product often comes down to considering your specific crop needs and growing requirements to see what works best for your application. Here are 15 LED products to take into account when choosing the right fit for your greenhouse.

Read More
Latest Stories

September 20, 2015

Technology Improves Orchid Production At Green Circle G…

Green Circle Growers in Oberlin, Ohio, has a commitment to using production practices that are efficient and sustainable. The operation has been growing Orchids for nine years, and is entering its second full year with its current system, which entails three camera grades. “The camera grading — first at production into a 5-inch pot, then 12 weeks later and a final grade after the stem and buds have developed — is raising our overall quality,” says Wesley Van Wingerden, director of growing for Green Circle Growers. Greenhouse Grower visited the operation to take a tour of its facilities and learn more about its Orchid production. Read on for more details about the process. The first of the camera grades is incorporated into the transplant process, which involves placing the Orchids from a community tray into 5-inch pots. The plants are separated into three sizes with the smallest returning to the […]

Read More

September 15, 2015

Young Plant Growers Weigh In On Crop Gains, Sales Trend…

Almost 100 young plant producers participated in Greenhouse Grower’s 2015 Young Plant Grower Survey, which asked growers questions abot crop categories, sales, order fulfillment and more.

Read More
Top20YPGrowers feature image

September 15, 2015

The State Of The 2015 Young Plant Market

Young plant growers in North America are changing their strategies to stay competitive in today’s market. Here is how 2015 shapes up in trends and statistics.

Read More
Vivero International_Endisch

September 8, 2015

Vivero Internacional Continues To Expand Unrooted Cutti…

The tenth largest cuttings farm in the world, Vivero Internacional was founded in 1991 and began exporting unrooted cuttings in 1993. Based in Tepoztlan, Morelos, just outside of Mexico City, Mexico, the operation opened with 2 hectares or 5 acres. With time and new customers, the farm has experienced rapid growth, now spanning 40 hectares or 99 acres, says Vivero’s Dennis Hitzigrath. “The first 10 years, production was doubling every season,” Hitzigrath says. “In the last three years, it’s been about 20 percent.”     The independent operation grows 100 million cuttings annually for several breeders, serving the North American market. Hitzigrath says consolidation among breeders has brought more of a focus on Vivero Internacional from third-party breeders in recent years. This growing interest is spurring even more growth. “We are planning for a minimum growth of 20 percent,” Hitzigrath says. “We are adding more production space and hope to be […]

Read More

August 19, 2015

Greenhouse Growing Recommendations For Lobularia

Modern-day Lobularias are garden classics with good vigor and long bloom times. These growing recommendations will help keep your crop in prime condition.

Read More
Mike McGroarty, owner of Mike’s Backyard Nursery

July 29, 2015

Backyard Success: Mike McGroarty Educates Aspiring Grow…

Mike’s Backyard Nursery sits on a long, narrow, 5-acre property located in Perry, Ohio. There, customers can find a variety of flowering shrubs available, all in 2-quart pots, and all for sale for $5.97 each. Owner Mike McGroarty, a lifelong resident of Perry, says the town has a lot of plant nurseries, including 100 wholesale growers within a 10-mile radius of his house. That doesn’t discourage McGroarty, because he knows that while there are a lot of nurseries in his area, no one else is doing what he is doing. McGroarty has learned about plants — and marketing them to his audience — through decades of experience. He has never hesitated to pass along his knowledge to other growers looking to start their own backyard operations, and has created an entire program to educate aspiring growers. McGroarty Likes To Practice What He Preaches McGroarty’s operation serves as the laboratory for […]

Read More
cannabis, marijuana plant

June 27, 2015

Concern Grows Over Unregulated Pesticide Use On Cannabi…

As most growers know well, the federal government regulates all insecticides, fungicides, herbicides and other commercial chemicals used on agricultural crops. Therein lies the problem with use of chemicals on cannabis crops – so far, the feds want nothing to do with legalized marijuana. According to “Concern Grows Over Unregulated Pesticide Use On Cannabis,” a June 17 article on the National Public Radio (NPR) network by Agribusiness Reporter Luke Runyon, the lack of regulated chemicals for cannabis has left growers to experiment on their own. “In the absence of any direction the subject of pesticide use on the crop has just devolved to whatever people think is working or they think is appropriate,” said Colorado State University Entomologist Whitney Cranshaw in the NPR report. “Sometimes they’ve used some things that are appropriate, sometimes unsafe.” Denver officials held tens of thousands of marijuana plants earlier this year due to safety concerns, but […]

Read More

June 16, 2015

The Butterfly Effect: Insect’s Wings Key To Azalea Poll…

A researcher from North Carolina State University (NC State) has found that in the case of the flame azalea (Rhododendron calendulaceum), all pollinators are not created equal. In fact, due to the flower’s unique reproductive structure, butterflies — and specifically, their wings — are the key to pollination. The flame azalea is commonly found in the Appalachian Mountains, ranging from as far north as New York to Georgia in the south. Like most azaleas, the flowers are large, and have an unusual structure: both the anther (male) and stigma (female) parts are very elongated and separated from one another. NC State biologist Mary Jane Epps was interested in how the azalea’s flower structure affected its pollination. “In order for a plant to reproduce, a pollinator — usually an insect — has to spread the pollen from the anther to the stigma,” Epps says. “In the case of the flame azalea, […]

Read More
Bee on a Sedum

March 17, 2015

4 Key Pollinator Research Projects To Be Funded By Hort…

The Horticultural Research Institute will grant $125,000 in financial support for four key projects as part of the Horticultural Industry Bee & Pollinator Stewardship Initiative. The Initiative has three primary goals. First, to convene a task force to develop a bee and pollinator stewardship program, including creation of best management practices for plant production. Second, to identify and fund research that will help answer key science questions and fill gaps needed to design and refine the stewardship program. Third, to seek to positively position the horticultural community and its customers by collaborating with other compatible groups interested in augmenting pollinator habitat and protection.

Read More

March 11, 2015

Pollinator Initiative Promotes Bee-Friendly Talking Poi…

AmericanHort and the Society of American Florists are working tirelessly with the ornamental industry's Pollinator Stewardship Initiative on a number of new projects.

Read More

February 11, 2015

Infusion Technology Boosts Seed Performance, Study Sugg…

Seven-year-old wheat seed germination can increase by as much as 83 percent, according to a Vital Force Technology Study that looks at the effects of energy infusion technology on plant vitality.

Read More

February 3, 2015

American Floral Endowment Accepting Research Pre-Propos…

If you are pursuing a floriculture research project, now is the time to apply for funding through the American Floral Endowment. Research pre-proposal applications for 2015-2016 funding are due to AFE by June 1, 2015.

Read More

January 27, 2015

Marijuana’s Trajectory And Ascent To Horticultural Cr…

Marijuana growing is poised for change as growers and researchers focus on improving production practices.

Read More

December 9, 2014

Greenhouse Production: Two Years Of Basics & Beyond…

Greenhouse Grower's Basics & Beyond articles cover some of the latest news and research going on in greenhouse production. Here are article links for the last two years.

Read More
GrowIt! App Wins Gold At Design100 2014 US Mobile & App Design Awards

November 24, 2014

GrowIt! App Wins Gold At Design100 2014 US Mobile &…

The social garden app GrowIt! takes the Gold Winner award at the design100 2014 Mobile & App Design Awards.

Read More

November 10, 2014

The Perennial Farm Joins HGTV HOME Plant Collection

The Perennial Farm joins the HGTV HOME Plant Collection growers' network for 2015.

Read More

November 4, 2014

AmericanHort Publishes Revised American Standard For Nu…

AmericanHort announces the revised American Standard for Nursery Stock (ANSI Z60.1) is now available for industry use. The Standard reflects the consensus of the industry regarding how nursery stock — living plants other than annuals — should be specified and sold within the trade.

Read More

September 26, 2014

Master The Art Of Watering

Watering is elemental to healthy plants, but one of the hardest concepts for new employees to master in the greenhouse. Recommend these tips to start them off right.

Read More
[gravityform id="35" title="false" description="false"]