Understanding Plant Nutrition: Low Media-EC

Slideshow: Understanding Plant Nutrition: Low Media-EC

When growers talk about “lack of feed” or “hungry plants” (Figure 1), the issue is usually insufficient supply of fertilizer nutrients. The easiest way to measure fertilizer level in the root media is with an electrical conductivity, or “EC,” meter.

What is Media-EC?

 
 
 

What Causes Low Media-EC?

The initial concentration of nutrients in a container media is provided by the pre-plant nutrient charge, which may include lime (providing calcium and magnesium), and other fertilizers such as superphosphate, gypsum or urea-formaldehyde. Part of the initial nutrient source is immediately soluble and therefore affects the initial media-EC. Other nutrient sources are bound to the soil particles or are in a slow-release form (e.g. limestone, resin-coated fertilizers), and only affect EC as nutrients dissolve into the soil solution.
Most media components, such as peat, bark or perlite supply a small amount of nutrients, whereas compost can supply significant nutrients as it decomposes and releases nutrients. 
Because of differences between batches of growing media, even from commercially blended products, it is important to not only know what your starting nutrient intensity is (as measured by EC), but also the composition and balance of the nutrients making up the EC (as measured with a complete soil test at a laboratory).
After planting, the goal is to balance deposits and withdrawals, in order to supply nutrients to the plant within an optimal level so they don’t get too high or too low. This is measured during the season by regular on-site EC testing.
You can picture the nutrients available for plant uptake in a pot using the analogy of a bank account (Figure 2).
We can increase the account balance by making deposits through salts contained in the irrigation water, with water-soluble fertilizer, or by surface-applying nutrients. Certain nutrients (carbon, nitrogen, oxygen and hydrogen) can be fixed from the air and water, but they do not contribute to soil EC unless they are dissolved ions in the soil solution.
The account balance is decreased by several types of withdrawal. These include nutrients taken up by roots for plant growth. The faster the crop is growing, the more nutrients are withdrawn from the crop and the more fertilizer needs to be deposited. Plants often require greater amounts of nutrients as growth rate increases during the middle of the crop, and less nutrients both when plants are very small or are mature and flowering. Some growers may increase the fertilizer concentration during this rapid growth phase, but keep the fertilizer concentration lower during the early and later stages of the crop.
Leaching is a very important type of withdrawal, because nutrients leaving the container can enter the environment and it is the one type of withdrawal that is completely controlled by the grower. 
Many growers routinely leach, but this is not needed if irrigation water contains few impurities such as sodium and chloride. Leaching washes nutrients from the pot, and leaching with clear water is therefore one way to reduce EC when the nutrient concentration is too high. However, the more a crop is leached on a routine basis, the higher the applied fertilizer concentration that is needed to maintain adequate nutrient levels in the root media. In other words, lower fertilizer concentration with low leaching can have the same effect on the EC account balance, with less cost, compared to a high leach/high concentration approach.
An excessively low EC means the nutrient balance can become “bankrupt” (i.e. there is inadequate nutrient level for healthy growth and plant stress occurs). You then need to deposit additional fertilizer. Figure 3 shows a low EC may occur if the starting balance is low, or if the withdrawals are occurring more rapidly than deposits.

Summary

Leave a Reply

More From Fertilization...
cannabis-nutrients

October 21, 2016

How To Select The Best Nutrients For Growing Cannabis

With a little bit of knowledge about the requirements of cannabis plants and how they absorb and utilize nutrients, you can confidently select the products you need without breaking the bank.

Read More
dramm-ferticart-feature

September 19, 2016

New Fertilizer Injector Cart Provides Full Aeration And Agitation

The new 50-gallon Ferticart from Dramm is designed to keep chemicals such as fungicides and plant growth regulators — as well as nematodes — viable through constant recirculation.

Read More
Roots with plant media background XL-W

July 2, 2016

University Of Florida Offering Online Nutrient Management Course In July

Topics include common nutrient problems, essential nutrients, fertilizer types, how to interpret a fertilizer label, managing total nutrient level, pH, and EC, onsite testing, and growing media.

Read More
Latest Stories
cannabis-nutrients

October 21, 2016

How To Select The Best Nutrients For Growing Cannabis

With a little bit of knowledge about the requirements of cannabis plants and how they absorb and utilize nutrients, you can confidently select the products you need without breaking the bank.

Read More
dramm-ferticart-feature

September 19, 2016

New Fertilizer Injector Cart Provides Full Aeration And…

The new 50-gallon Ferticart from Dramm is designed to keep chemicals such as fungicides and plant growth regulators — as well as nematodes — viable through constant recirculation.

Read More
Roots with plant media background XL-W

July 2, 2016

University Of Florida Offering Online Nutrient Manageme…

Topics include common nutrient problems, essential nutrients, fertilizer types, how to interpret a fertilizer label, managing total nutrient level, pH, and EC, onsite testing, and growing media.

Read More
Agro-K

May 19, 2016

Agro-K Expands Distribution In New England Through Part…

Agro-K, which manufactures conventional and organic foliar plant nutrients, will distribute its full line of foliar fertilizers and soil biological products through NEAG.

Read More
Fertilizer Rates Feature Image

January 29, 2016

Bioworks Releases New Higher Nitrogen Fertilizer For Or…

Verdanta N-Vita 9-4-3 promotes foliar growth and features a slow release process, making nutrients available for a longer period of time.

Read More
Primrose Downward Leaf Roll From Calcium Deficiency

January 11, 2016

How Calcium Plays A Critical Role In Plant Health

Supply vegetables and poinsettias with a healthy amount of calcium to avoid tip and leaf burn.

Read More
Sustane Research Greenhouse 2015

January 7, 2016

Fertilizer Manufacturers Aim To Deliver Sustainable Sol…

Industry experts discuss the latest trends to help ensure 2016 is your best year yet.

Read More
Fertilizer Rates Feature Image

August 12, 2015

Selecting Fertilizer Rates For Several Spring Bedding P…

Fertilizing bedding plants can be difficult due to the differing needs of the large variety of plants that we grow. Many operations do not grow enough of any one crop to cater the fertilizer specifically for each crop. Therefore, grouping crops with similar fertilizer requirements and having two to three fertilizer strengths available is a practical way to ensure plants are getting the fertilizer they need. With many new plant varieties on the market, we wanted to conduct a trial at Cornell University to determine best fertilizer rates for several common bedding plant crops. 22 Bedding Plants Studied To Establish Fertilizer Rates Plugs and rooted liners of 22 crops (Table 1) were transplanted into 4-inch (500 mL volume) round pots with a commercial peat/perlite based substrate. The plants were grown in a glass greenhouse at Cornell University during the spring season at a spacing of one plant per square foot. Heating set […]

Read More
NSOrganicPlantFood3-1-1_featured

June 13, 2015

UMASS Fertilizer Trials Recommend Nature’s Source Organ…

In a recent online fact-sheet at its Extension website, the UMass Amherst Center for Agriculture, Food and the Environment lists Nature’s Source Organic Plant Food 3-1-1 as “the best liquid organic fertilizer,” according to Dr. Douglas Cox, Stockbridge School of Agriculture. It is called-out by the Extension after a number of years of studying the use of organic fertilizers for growing commercial greenhouse crops. The trials evaluated traditional water soluble and granular slow-release chemical fertilizers. Dr. Cox recommends Nature’s Source Organic Plant Food 3-1-1 as a liquid fertilizer that is readily available, cost effective, OMRI-listed and with good label directions for greenhouses. He also mentions the ease-of-use in how it mixes well with water and can pass fertilizer injectors. “Nature’s Source is currently the best liquid organic fertilizer,” Cox wrote in his article “Organic Fertilizers – Thoughts on Using Liquid Organic Fertilizers for Greenhouse Plants,” “I have seen no foliar chlorosis yet with this fertilizer. Nature’s source is widely available and a great […]

Read More

January 9, 2015

6 New Fertilizer Products For Healthy Plants

These five products add even more options for delivering nutrients to the root zone.

Read More

January 7, 2015

Fertilizers And The Future

As growers look for new ways to cut costs and conserve resources, fertilizer and equipment companies are offering products that strive to save water, reduce toxic runoff and keep chemicals out of the equation.

Read More

December 31, 2014

Gain Greater Control Of Fertilizer With Automated Ferti…

University researchers look at integrating irrigation and fertilization with the help of water sensors to reduce fertilizer treatments and improve application timing.

Read More

October 30, 2014

Basics & Beyond: Comparing Substrate Fertilizer Ame…

Cornell University researcher determines if substrate-incorporated slow-release fertilizers can be used to replace or reduce the need for liquid fertilizer for four spring crops.

Read More

July 24, 2014

Using Controlled Release Fertilizers To Produce Garden …

Researchers determined whether or not garden mums can be grown with controlled-release fertilizer, and if it reduces fertilizer leaching, as compared with water-soluble fertilizers.

Read More

March 14, 2014

New Foliage Pro Fertilizer Offers Complete Nutrition Pl…

Dyna-Gro Nutrition Solutions has developed a process it says is capable of keeping all 16 essential plant nutrients in solution form.

Read More

January 30, 2014

OASIS Grower Solutions Introduces New One-Bag Hydroponi…

The new 16-4-17 Hydroponic Fertilizer from OASIS Grower Solutions (OGS) is a one-bag solution that replaces two-part systems traditionally used by commercial hydroponic growers. It is specifically formulated for commercial hydroponic production of lettuce, herbs and vegetables.

Read More

December 30, 2013

Fertilizer Changes Growing Mix pH

When considering a fertilizer's influence on media pH, you need to know its acid or basic reaction.

Read More

December 30, 2013

Basics & Beyond: Fundamentals Of Phosphorus Nutriti…

Phosphorus is an essential element, after all.

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