Switching To Organic Fertilizer

Basil seedlings, Control and 3 organic fertilizer treatments
Basil seedlings treated with organic fertilizers four weeks after sowing. Left to right: Control, no fertilizer; Sustane 8-4-4; Worm Power vermicompost extract drenches; Sustane plus vermicompost extract.

Converting an operation to using organic fertilizer is a more complex process than simply using a new brand. There are several factors a grower needs to consider and plan for before making the decision to change.

Most growers who make the switch, says Neil Mattson, associate professor of horticulture at Cornell University, do so because the market demand is there for it to make sense financially.

If you are thinking of growing organically, here are the issues you need to consider, according to Mattson.

It’s Easier For Short Term Crops

Mattson says those growers who change from using conventional to organic fertilizers, who have had to make the biggest adjustment, are usually the ones producing plants with a longer production cycle.

“For growers who are producing vegetable seedlings or transplants, the change to organic fertilizers has not been too difficult,” he says. “For growers producing vegetables hydroponically or growing longer-term crops that will be in a greenhouse for several months, the transition is more difficult.”

Look For The Right Fertilizer

Mattson has done numerous research studies comparing the differences between conventional and organic fertilizers and says he has not yet found an organic fertilizer that offers the same amount of control and flexibility as conventional fertilizers.

“Growers have to adapt their cultural practices to the type of organic fertilizer choices that they have available to them,” he says.

One of the difficulties for growers of long-term organic crops is making sure plants are supplied with enough nutrients.

Also, some organic fertilizer sources are high in salts, which can accumulate and can have a negative impact and damage the plants over time.”

Mattson says another concern with organic fertilizers is the potential for nutrient imbalances. For many organic fertilizers, some quantity of all nutrients are being supplied. It can be difficult to pick and choose a fertilizer or complementary fertilizers to supply exactly what the plants need and nothing else.

“With conventional fertilizers, growers can supply specific elements in the ratio required by the plants,” he says. “With organic fertilizers, if a deficiency develops, such as an iron deficiency, there are not a lot of individual nutrient tools available to increase the rate of that element.”

Match The Fertilizer To The Crop

Growers who have been successful using organic products have been able to determine the right use for them in their production systems, Mattson says.

The most successful growers of short-term vegetable or bedding transplants use organic fertilizers, added to their potting mix ahead of time.

“These are usually granular poultry-based fertilizers, such as microSTART and Sustane or a blend of several components such as EcoVita,” he says. “They are quite high in the nutrients they supply, in regard to nitrogen, phosphorus and potassium.”

Mattson has been successful incorporating these granular fertilizers (microSTART60 Plus 7-2-2l Sustane 8-4-4 and EcoVita 7-5-10) into the potting mix for vegetable transplants like tomatoes. He found a rate of 0.64 pounds of nitrogen per cubic yard worked well.

The granular fertilizers performed well for several weeks before their effectiveness eventually dwindled, he says.

“That’s when a grower basically has two choices. He can either topdress with more of the granular fertilizer or supplement with a liquid fertilizer.”

Organic fertilizers tend to be a little more expensive than their mineral counterparts, but Mattson says granular formulations have become a cost effective way for growers to apply organic fertilizers.

Consider How Water Impacts Fertilizer

Changing to organic fertilizers for a long-term vegetable crop would be similar to using them for a long-term ornamental crop, Mattson says.

“For the first few months, a grower would have to reapply organic fertilizer several times,” he says.

The most difficult production method would probably be growing vegetables hydroponically, because the grower is has to rely solely on the hydroponic solution to deliver nutrients.

Mattson recommends vegetable growers use a bag culture with a large reservoir, such as a 5-gallon bag.

“This would help to supply a larger reservoir of nutrients,” he says. “That’s going to get more nutrients to the plants. Also, granular organic fertilizers could be applied to build up the fertility in the potting mix.”

The potting mix would also act as buffer for pH and salts. A grower could monitor the substrate and leach if necessary to keep the salt levels under control.

“If it was a true hydroponic production setup and the grower was collecting and recycling the irrigation water, the salt levels could buildup relatively quickly,” Mattson says. “The alternative would be to dump out the fertilizer solution and start all over again.”

A grower using a hydroponic solution to fertilize would have to monitor his water for salt buildup.

“Many growers monitor pH and salts manually at least once a day and make the appropriate adjustments,” he says.

Sensors can also be problematic, since they can change over time.

“They should occasionally do some manual monitoring to make sure that the pH hasn’t changed,” Mattson says. “Those sensors may need to be recalibrated.”

Water alkalinity can cause the pH to change, and water supplies in the Midwest and West often have high alkalinity.

“Water alkalinity includes dissolved carbonates and bicarbonates in the water,” he says. “The pH of the water is going to naturally rise over time as the carbonates build up, whether growers are using grow bags or a hydroponic solution.”

Another thing that can affect the pH is the form of nitrogen fertilizer. As plants take up ammonium nitrogen, the pH is going to decrease. As plants take up the nitrate form of nitrogen, the pH is going to increase.

“With conventional fertilizers, we can closely predict what is going to happen with the pH because we know exactly the ratio of ammonium and nitrate,” Mattson says. “For example, a 21-5-20 fertilizer consists of 60 percent nitrate nitrogen and 40 percent ammoniacal nitrogen. That tends to be a slightly acidic fertilizer.”

Most of the nitrogen is not in the nitrate or ammonium forms of organic fertilizer, rather, the organic material needs to be digested by microbes to release the nitrogen, Mattson explains.

“That results in ammonium, which the microbes can further convert to nitrate,” he says. “With organic fertilizer, the microbial process is necessary to create ammonium and nitrate forms of nitrogen.”

Temperature Affects Performance

Organic fertilizers are dependent on microbes to break them down into nitrogen forms the plants can use. Mattson says the nutrient availability of organic fertilizers is temperature dependent.

“If a crop is being grown at cool temperatures, it is going to be very difficult for the organic fertilizer to supply enough nutrients,” he says. “Whereas with the conventional fertilizers, nitrates are soluble in water and are ready to be taken up by the roots.”

Mattson conducted an experiment with tomato transplants that were grown for six weeks with either organic or conventional fertilizers at 50ºF, 60ºF and 70ºF.

“The organic fertilizers performed well at 60ºF and 70ºF, but they did not perform very well at 50ºF,” he says. “Tomato plants, in general, don’t grow very fast at 50ºF, but at 50ºF the plants that received conventional fertilizer were twice the size of the organic-fertilized plants. When the air temperature is cool, the microbes are still going to be less active in converting nitrogen to forms that the plants can use.”

Topics:

Leave a Reply

More From Crop Inputs...
Bees And Pesticides

August 23, 2016

Studies Offer Conflicting Views On Neonic Effect On Bee Health

How much exposure to neonicotinoids do bees need before their health becomes affected? That’s the question two research teams look to answer.

Read More
Chrysanthemum Aphid

August 22, 2016

How To ID And Manage Black Aphids In Chrysanthemums

Growers in Michigan have recently been reporting a higher presence of this pest. Here are some tips on how to control it.

Read More
Cannabis Crop Protection

August 22, 2016

Cannabis Group Stays Focused On Consistent Standards For Crop Protection

The Foundation of Cannabis Unified Standards (FOCUS), is an independent, third-party, not-for-profit organization, is in the process of developing cannabis-specific standards for everything from cultivation and extraction to packaging and retail.

Read More
Latest Stories
Bees And Pesticides

August 23, 2016

Studies Offer Conflicting Views On Neonic Effect On Bee…

How much exposure to neonicotinoids do bees need before their health becomes affected? That’s the question two research teams look to answer.

Read More
Chrysanthemum Aphid

August 22, 2016

How To ID And Manage Black Aphids In Chrysanthemums

Growers in Michigan have recently been reporting a higher presence of this pest. Here are some tips on how to control it.

Read More
Cannabis Crop Protection

August 22, 2016

Cannabis Group Stays Focused On Consistent Standards Fo…

The Foundation of Cannabis Unified Standards (FOCUS), is an independent, third-party, not-for-profit organization, is in the process of developing cannabis-specific standards for everything from cultivation and extraction to packaging and retail.

Read More
Leaf Septoria In Cannabis

August 21, 2016

Three Diseases To Watch For In Cannabis Production

The development of root rot, powdery mildew, and leaf septoria can damage cannabis to the point of complete crop loss.

Read More
Greenhouse Whitefly

August 18, 2016

Vestaron Planning For More Research And Development Of …

On the heels of launching Spear-T, its first bioinsecticide, Vestaron has received additional financing that will be used to develop new products with new modes of action.

Read More
BioWorks Mycotrol

August 17, 2016

New Organic Mycoinsecticide From BioWorks Now Registere…

BioWorks’ Mycotrol can be used to manage whitefly, thrips, aphids, and other insects in greenhouses and nurseries.

Read More
Downy mildew lesions on light coleus cultivars feature

August 12, 2016

How You Can Control Downy Mildew In Coleus, Roses, And …

Downy mildew diseases are potentially devastating to ornamental crops and at the very least can cause unsightly damage. Check out the latest research and recommendations for preventing it.

Read More
Jen Browning BASF

August 4, 2016

Horticulturist And Entomologist Jen Browning To Speak A…

Browning will discuss the use of nematodes in managing pests in greenhouses and nurseries.

Read More
Poinsettia, Heavy Whitefly Infestation -Lower Leaves, Insect - Feature

August 3, 2016

Tips For Successful Late-Season Whitefly Control

Managing late-season whiteflies successfully on poinsettia requires preventative measures put in to action early in the production cycle.

Read More
Cannabis Crop Protection

July 28, 2016

Solving The Cannabis Crop Protection Problem

A largely unregulated sector of the industry, state departments of agriculture, biocontrols companies, and other industry pros are dedicated to helping growers make the right pesticide decisions for their operations.

Read More
Aphids On Older Leaves

July 25, 2016

How You Can Stop Aphids By Understanding Their Interact…

Knowing which aphids target which crops and how aphids colonize and move on plants goes a long way toward setting up an effective management plan.

Read More
BASF Orkestra Intrinsic

June 21, 2016

New Mode Of Action From BASF Offers Deeper Disease Cont…

When it comes to disease control, you need all the help you can get. BASF recently hosted growers, Extension personnel, and trade media to present its newest fungicide with two active ingredients, offering dual modes of action.

Read More
Nematodes-feature

June 4, 2016

New Biocontrols Provide Effective Pest Control In Green…

Biological chemistry manufacturers have introduced several new products recently that offer a range of insect and disease management options. Here’s a look at some of them.

Read More
Whitefly

June 2, 2016

Breaking News: Florida Growers Reporting Major Whitefly…

Reports have come from the Florida Keys to Palm Beach County that whitefly populations in landscapes are reaching unprecedented levels and are not responding to pesticide applications. Biotype-Q has been found in four different communities. University of Florida/Institute of Food and Agricultural Science researchers are working with USDA-APHIS, USDA-ARS, the Florida Department of Agriculture, and growers and landscape professionals to manage the developing problem.

Read More
Triathlon BA container shot

May 24, 2016

OHP’s Triathlon Biofungicide Now Listed By The Organic …

Triathlon BA is a broad-spectrum preventative biofungicide that provides control of many foliar and soilborne diseases in ornamentals and herbs.

Read More
Two-spotted spider mites, adults and eggs

May 11, 2016

SePRO Launches Summer Insecticide Management Program Fo…

The program is designed to help growers use SePRO’s insect management tools to prevent plant damage from a variety of pests.

Read More
Small Aphid Colony on Calibrachoa

May 2, 2016

How To Stop Aphids In The Greenhouse

When untreated, aphids damage ornamental crops and act as vectors for disease. Integrated Pest Management combined with vigilant scouting can help you stay ahead of the problem.

Read More
Cicada (Greg Hoover, Penn State)

April 26, 2016

Cicadas Set To Emerge In Several Eastern States This Sp…

While there’s no immediate cause for alarm, experts say the cicada’s egg-laying process can damage woody ornamentals and make them vulnerable to diseases.

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