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.”


Leave a Reply

More From Crop Inputs...

November 30, 2015

Four Garden Retailers Share Their Secrets To Selling Sustainable Products

Some garden retailers have the magic touch when it comes to selling organic and other natural products. We reached out to four such retailers to find out why the category sells so well for them. Take a look at what they say is the secret to selling sustainable products. Educating Customers Is A Must-Do It’s vital to educate customers about the ingredients in organic products, as well as how to apply them and setting expectations about efficacy and the amount of time they take to work, experienced retailers say. Doing so ensures success on the part of the customer and continued profitability of the product line. “We do a weekly eMail and a weekly Saturday morning garden walk, as well as a daily blog,” notes Nancy DuBrule-Clemente, owner of Natureworks in Northford, Conn. “We update our Facebook page all of the time and we have more than 50 handouts on […]

Read More

November 30, 2015

A Guide To How Organic Active Ingredients Work [Cheat Sheet]

There are few resources that spell out how organic active ingredients work, so we looked up the most commonly used active ingredients and began hunting them down (primarily through USDA and EPA). Here's a quick guide to organic active ingredients and how they work to share with your staff.

Read More
2015 Trial beds at the Dallas Arboretum (2015 Dallas Arboretum Field Trials)

November 30, 2015

2015 Dallas Arboretum (Dallas, Texas) Field Trials Results

See the 2015 field trials results (includes photo gallery) for the Dallas Arboretum in Dallas, Texas.

Read More
Latest Stories
Stockosorb Crystals_with water Agriculture leaf (Evonick)

November 21, 2015

9 Sustainable Growing Media Products For Superior Green…

Manufacturers are delivering new growing media products to help growers attempt to minimize their footprint without sacrificing quality. Here are nine new products to consider for your greenhouse operation.

Read More
Suzanne Wainwright-Evans

November 16, 2015

Real-World Biocontrols Trends From The Buglady

During ,em>Greenhouse Grower's Top 100 Breakfast at Cultivate'15, Suzanne Wainwright-Evans of Buglady Consulting discussed trends in biocontrols, including what she has seen from breeders, growers and even public gardens.

Read More

October 13, 2015

Bayer CropScience And OHP To End Marketing Partnership …

The move allows Bayer to market its ornamental products directly to greenhouses and nurseries, although OHP will still service a limited line of Bayer products.

Read More
RISE 2015 Governing Board

October 13, 2015

RISE Annual Meeting Celebrates 25 Years of Industry Adv…

The annual meeting for RISE (Responsible Industry for a Sound Environment), held the last week of September in Orlando, was more than just presentations, awards and the election of new officers. It was also a celebration of 25 years as a leading advocate for the specialty pesticide and fertilizer industries.

Read More

October 9, 2015

New Biochemical Miticide Is Designed To Combat Varroa M…

EPA recently registered Potassium Salts of Hops Beta Acids (K-HBAs), which is intended to fit into a rotation program to battle resistance.

Read More

October 7, 2015

Ball FloraPlant Eliminates Neonicotinoid Use On Its Off…

Ball FloraPlant has announced its offshore cuttings farms did not use neonicotinoid-based pest management chemicals during its spring crop production last shipping season, and will continue to be neonic free this year. Instead, the company and its greenhouse managers have relied on alternative means to supply insect-free cuttings to its global customer base.

Read More
Nemasys And Millenium Beneficial Nematodes from BASFm_Nematodes

October 7, 2015

How BASF’s UK Biological Production Facility Expa…

BASF has expanded its biologicals production facility in Littlehampton, UK. The new capacity increases the company’s ability to double the production of beneficial nematodes and inoculants.

Read More

September 25, 2015

Canadian Sphagnum Peat Moss Association Announces Early…

According to an August 31 survey of members of the Canadian Sphagnum Peat Moss Association (CSPMA), whose members represent approximately 95 percent of all North American peat production, the peat harvest season has been adequate, but not strong, and could cause shortages and potentially higher transportation costs. Down To The Dirty Details The survey inquired about the status of CSPMA members’ 2015 Actual Harvest (including an estimate of what can be expected to be harvested for the remainder of the season) as a percentage of their 2015 Expected Harvest. The lack of a strong harvest overall may challenge peat availability. The Prairie Provinces (Manitoba 98 percent, Saskatchewan 88 percent and Alberta 94 percent), experienced early favorable weather conditions and a strong start to the year. This helped to minimize periodic, negative, weather-related conditions during the balance of the harvest season, and the harvest numbers are close to achieving the expected amounts. […]

Read More

September 23, 2015

New Crop Protection Products And Label Updates

Here are some of the most recent products released and label updates for crop protection agents in the greenhouse and nursery market. Fame Fungicides (FMC Corp.) FMC Corp. has introduce Fame fungicides, a family of FRAC 11 group (Strobilurin) products that delivers fast-acting, patented fluoxastrobin protection against major soil and foliar diseases. Rainfast in 15 minutes, Fame fungicides can be used on most greenhouse and nursery plants and provide fast foliar and root uptake. “Proven by university research, Fame fungicides offer fluoxastrobin action, which ensures a high degree of systemic activity to provide very rapid disease protection and stop further growth of established disease,” says Naimur Rahman, strategy and fungicide marketing product manager for FMC. The Fame fungicide family includes: • Fame SC: a suspension concentrate fungicide containing fluoxastrobin that controls major diseases, including anthracnose, downy mildew, powdery mildew, scab and leaf spot. It provides rapid foliar and root uptake […]

Read More
Offshore farm profiles Dummen Orange Las Mercedes Solanaceas GH

September 8, 2015

Dümmen Orange Implementing Consistent Standards On All …

Owning and operating several locations can be a challenge in maintaining consistent quality and cleanliness across the board. This is true of both breeders and growers. But those who do it right have invested in technology and practices that ensure that plant quality matches, no matter where their plants are shipped from. That’s the goal for Dümmen Orange. Now the world’s largest producer of unrooted cuttings, the company has a combined 150 hectares or 370 acres of production space worldwide, dedicated to cuttings production. Recent acquisitions of product portfolios, both this year and in the past few, has raised the company’s cuttings production expectation to more than 1.4 billion, including 350 million in North America. It has farms all over the world (see the 2015 Top Cuttings Producers ranking to see where), and produces cuttings for its own genetics, as well as collaborating with more than 30 third-party breeders across all […]

Read More
Bill Lewis grower manager at Delray Plants

August 31, 2015

Delray Plants Takes Preventative Approach To Pest Contr…

Trying to control pests effectively on a wide variety of crops is a major undertaking. Delray Plants in Venus, Fla., has been using biological controls as a part of its pest control program for more than 10 years. It operates 300 acres, which includes covered structures and 7 acres of outdoor field production.

Read More
Bob’s Market and Greenhouses’ Ron Morris pours Stockosorb into the hopper for distribution on the conveyor line

August 13, 2015

How Bob’s Market And Greenhouses Improved Growing…

My father started our company 45 years ago growing bedding plants, mainly early season production and finished plants for our West Virginia market. It was in the early 1980s that we started growing earlier spring production and shipping materials to southern markets, and by the late 1980s, we also produced pansies for fall. We started using hydrogels when they first came on the market in the early 1990s and found that they really helped with our production by keeping plants healthier for these new markets. Over the years, we’ve grown to be a large young plant producer and have a sizable business growing finished plants in cell packs, 4 1/2-inch pots, 6-inch pots, gallon containers, hanging baskets, multiple sizes of large containers and large baskets for municipal use. Creating The Ideal Soil Mix With our old system, it took several workers to mix pre-made soil with slow-release fertilizers in cement […]

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
Feature image The Aphid Guard Aphid Banker Plant, coming soon to the market, supports beneficial insect populations.

June 21, 2015

The Latest In Crop Protection

Protecting your plants from the latest threats is no easy task, but new product lines promise to safely and effectively eliminate a wide range of pests and diseases, without harming your employees or the environment.

Read More
Bee On Flower

June 18, 2015

Pest Management And Marketing Strategies For Bee-Friend…

Michigan State University Extension shares pest management practices to produce plants that are safe for pollinators and marketing strategies for clearing up confusion about bee-friendly plants.

Read More

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

June 10, 2015

BASF’s Sultan Miticide Receives California Regist…

BASF Sultan miticide recently received registration in California, giving ornamental growers a new rapid, targeted mode of action for mite control. Sultan miticide, with active ingredient cyflumetofen, offers ornamental growers targeted knockdown of all life stages of tetranychid mites, with long residual control. It has practically no toxicity to beneficial insects, including predatory mites and pollinators. Sultan miticide offers a new mode of action to combat cross-resistance with other commercial miticides, and is compatible with integrated pest management programs (IPM). “The long-awaited California registration of Sultan miticide is exciting news. Greenhouse, nursery and landscape professionals in the state now have a new class of chemistry that gives them fast control over all life stages of plant-damaging mite populations,” says Joe Lara, senior product manager for BASF. “Sultan miticide now provides California growers with a much needed new first choice for miticide resistance management programs that won’t disrupt populations of beneficial […]

Read More
Bee on a Sedum

May 27, 2015

Industry Associations State Their Support Of National P…

AmericanHort, Society of American Florists, American Floral Endowment and Horticultural Research Institute joined together to embrace key aspects of the federal government’s recently announced National Strategy for the Protection of Honey Bees and Other Pollinators. The long-awaited strategy has three major goals: reducing honey bee colony losses, increasing Monarch butterfly populations, and restoring or enhancing millions of acres of land as pollinator habitat through public and private action. According to the statement, the associations are studying the details, but they agree that the overall approach appears balanced and mostly sensible. The rest of the statement reads as follows: “The national strategy’s overarching goals dovetail well with the focus of the ongoing Horticulture Industry Bee and Pollinator Stewardship Program. Under that initiative, we have directly funded several priority research projects, and collaborated on additional research funded by others, to provide critical scientifically sound guidance for professional horticulturists. We are developing a grower […]

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