December 3, 2008

New Technologies In Nutrition

The Scotts Company celebrated its 140th anniversary this year, and it evolved greatly since the days of O.M. Scott. The last 25 years have certainly brought many innovative changes to the ornamentals industry as a whole. What will happen in the next 25 years? There will surely be many changes in ornamental production, some that will be impossible to predict at this point in time. However, some recent trends are expected to continue into the foreseeable future: more large production operations, more automation, increasing pressures to reduce material costs, labor and shrinkage, and additional need to reduce waste, environmental impact and adopt sustainable practices. There’s little doubt that the sustainability movement within the horticulture industry will continue to be at the forefront of our industry’s consciousness. As a result, Scotts has developed “The e3 Approach to Sustainability,” which advocates the balance of three important elements–efficiency, economy and ecology–for a more […]

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October 21, 2008

Understanding Plant Nutrition: Managing Media pH

Managing the pH of container media is a challenge in the greenhouse and nursery industry. Many growers face problems associated with their media pH either drifting up or down to levels that result in loss of crop quality and sales. In this article, we will discuss how the factors that we have discussed in previous articles (media, lime, water, fertilizer, etc.) interact to affect pH management. Balancing Factors Consider pH management as a balance (Figure 1). One side of the balance has the basic reactions commonly found in container media (i.e. the reactions that make the media pH increase). The four main basic reactions are: nitrate (NO3-N) fertilizers, irrigation water alkalinity, reactive lime and residual lime. On the other side of the balance are the acidic reactions (i.e. the reactions that make the media pH decrease). The three main acidic reactions are ammoniacal (NH4-N) fertilizers, media lime requirement and plant […]

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September 17, 2008

Understanding Plant Nutrition: Controlled- And Slow-Release Fertilizers

Using controlled-release (CRF) and slow-release (SRF) fertilizers allows growers to supply nutrients for an extended duration without the specialized equipment needed to apply water-soluble fertilizers. These fertilizers are added to the media at mixing or applied to the media surface after planting. Nutrient runoff can be reduced using CRF and SRF, especially compared to applying water-soluble fertilizer through overhead sprinklers. Relying on CRF alone is not always the best solution for nutrient management. For example, even distribution of CRF prills from plant to plant is difficult when growing in cell packs or trays. The correct CRF should be matched to the crop and growing environment so that nutrients are released at the rate required for optimal plant growth – too rapid a release rate can cause media-electrical conductivity to climb too high and damage roots, or too slow a release can result in nutrient deficiencies. In some cases, a combination […]

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August 25, 2008

Powerful Poinsettias

Producing poinsettias in today’s competitive market requires a great commitment of time and energy (and a bit of Tylenol). Taking steps that make your operation more sustainable can greatly increase your overall efficiency, reduce waste and boost your price per finished plant. Preventing nutrient imbalances that lead to deficiencies and toxicities can add a few extra steps at the start of the season, but you will reap the rewards, not to mention avoid the devastating damage a disease can spread throughout your entire greenhouse. Tracking the nutrient and disease status of your crop will improve your efficiency by saving you time on the end. Here are some ways crop tracking can improve your plant quality as well as overall sustainability. An ounce of prevention is worth a pound of cure; it may be a cliché, but its message is worthwhile. As we come into another poinsettia season, we often are […]

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July 8, 2008

Understanding Plant Nutrition: Fertilizers And Media pH

Choosing fertilizers can be one of the most important decisions you can make for managing the media pH of container grown crops. It is therefore important to understand how fertilizers raise or lower media pH, which results largely from the form of fertilizer nitrogen (ammoniacal, nitrate or urea). This article will help you understand why fertilizers are classified as acidic or basic and how the reactions produced by the fertilizer affect media pH.  You Can’t Measure Fertilizer Acidity With A pH Meter! Here is a trick question: Which is the most acidic fertilizer in Table 1? The table shows the nitrogen (N):phosphorus (P2O5):potassium (K2O) ratio, the fertilizer label description in terms of potential acidity or basicity, along with the percent of nitrogen in the ammoniacal form (the rest of the nitrogen in these formulas is made up of nitrate). We prepared a solution of 200 parts per million of nitrogen […]

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June 20, 2008

Managing Nutrition In Spring Crops

The spring season presents some unique challenges for even the best growers. It can be a time of rapidly changing environmental conditions – some beyond the grower’s control – that may negatively impact crop quality. Often, growers plan multiple crop turns to meet desired shipping dates that are subject to last minute shifts due to fluctuating weather and market conditions. Plus, there are hundreds of different spring crops available, making even more it difficult to stay on top of their various nutritional needs. To further complicate matters, this enormous list of spring crops continues to expand every day. Managing the nutrition of spring crops can be compared to running a diner with a gigantic menu that includes various eclectic offerings from Italian to Chinese. I’ve often wondered how the cooks in those establishments are able to efficiently supply such a wide variety of meals on demand at a relatively low cost. […]

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June 20, 2008

Misconceptions With Controlled Release Fertilizers

Pilon: How do rates vary between incorporation and topdressing? Passchier: There are two factors involved when speaking about incorporation and topdressing the fertilizer. The first is the potential differences in nutrient availability for the plant when incorporating versus topdressing. The second is the amount of fertilizer that is used when incorporated compared to the topdressing rate. Let’s remember that CRF fertilizers are released by temperature and research shows that different technologies are affected by the temperature changes around the CRF prill that can alter their expected release. Just think about the temperature fluctuations and moisture consistency in the media versus the temperature fluctuation and moisture consistency on top of the media. In general, there is likely to be less temperature fluctuation and more moisture consistency in the pot than on the surface of the pot. The surface of the media is subject to greater temperature changes between night to day […]

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June 19, 2008

Q&A On Controlled-Release

Pilon: What are the methods controlled-release fertilizers (CRF) are applied? Passchier: The two most common methods of applying controlled-release fertilizers in greenhouses and nurseries is to incorporate them into growing mixes prior to planting (incorporation) or placing the fertilizer on top of the potting substrate (topdressing). Topdressing entails placing a predetermined amount of fertilizer on top of the growing medium of each container. Generally, topdressing is reserved for second-season crops, but there are some growers who topdress crops just after planting new liners. Care should be taken with this practice to make sure you have a first-season fertilizer and not a second-season topdress fertilizer. The first method I was exposed to 15 years ago was the "big hand" method. The grower/owner would show the hired help how much fertilizer to put in their hands and then place it on the surface of the container. Needless to say, the size of […]

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June 18, 2008

Misconceptions About Controlled—Release Fertilizers

Delivering and managing nutrition is one of the primary tasks associated with producing greenhouse crops. Most growers deliver nutrients using various water-soluble fertilizers, some growers use controlled-release fertilizers (CRF), while others use a combination of controlled-release and water-soluble fertilizers. As I travel across the country to visit various growers, I’ve come to recognize that many growers would like to consider using controlled-release fertilizers at their facilities but do not understand these products well enough to implement them into their production systems. With a shift in irrigation and fertility practices, where growers must control leaching and water runoff from their production sites, the use of controlled release fertilizers will allow growers to produce high-quality crops and manage the nutrients that leave their production sites more effectively. From my perspective, there is a great need to educate growers of the benefits and risks associated with the use of controlled release technology. To help […]

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June 18, 2008

What’s In Controlled-Release?

In the first installment of this four-part series, we began to introduce several important aspects regarding controlled release fertilizers (CRFs). Slow-release fertilizers are reacted urea formaldehyde products. Each has its own characteristic chain of polymers, which are gradually broken off by microbial activity and then made available for roots to uptake. Controlled-release fertilizers are fertilizers with nutrients that are encapsulated or coated, similar to an M&M candy, where there is an outer candy coating and the good stuff inside the coating. Fertilizer is released when moisture is drawn into the covered coated prill and turns the fertilizer salt into a semi-soluble form. The release of nutrients from the prill varies slightly with the technology used to formulate the coating. All CRFs typically have either a resin or polymer coating. The main difference is how the water soluble fertilizer comes out of the prill. The rate of release is often a function […]

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June 18, 2008

Talking Temperature

Pilon: How does temperature affect release? Passchier: As we discussed previously (see the July 2007 issue), controlled release fertilizers can be compared to M&M candy since the good stuff is inside of the coating of each of these products. As the temperature increases so does the solubility of the candy and fertilizer on the inside. The main difference is the inside of the coated prill of the fertilizer contains some form of salt. Moisture needs to be present around the coated fertilizer prill in order for moisture to be drawn inside allowing the solid fertilizer salt to turn into a semi-soluble state. As the temperature increases, so does the solubility and the pressure inside the prill. Consequently, with higher temperatures and increased internal pressure, it requires less time for the fertilizer to come out of the prill and be available for plant uptake. The trick to formulating and using CRFs […]

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