June 4, 2009
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 […]
April 25, 2009
Understanding Plant Nutrition: High ph Problems
High media-pH (above 6.4) induced iron deficiency is the most common nutritional problem for certain iron-inefficient crops (Figure 1), including calibrachoa, diascia, nemesia, pansy, petunia, scaevola, snapdragon and vinca. Plants only take up dissolved nutrients through their roots. When the media-pH is too high, micronutrients (especially iron) are less soluble and unavailable for uptake by plant roots. High-pH induced iron deficiency can develop within one to two weeks, resulting in chlorosis of new growth and overall stunting. This problem is not occurring because plants need more “feed” or are “heavy feeders.” Instead, it occurs because the iron supplied in fertilizer becomes insoluble due to the high media pH. Getting Started We have undertaken considerable research and worked closely with growers to develop strategies to rescue crops that are stressed from high media-pH. If you think there is a problem, the first thing to do is test the pH and electroconductivity […]
March 23, 2009
Understanding Plant Nutrition: Correcting Low Media pH
Iron/manganese toxicity is a common problem when media-pH drops below the ideal level in certain crops, including geraniums, marigolds, lisianthus, and pentas. As media-pH decreases (meaning the pH becomes more acidic), iron and manganese become more soluble, resulting in higher concentrations in the soil solution. For each drop in media-pH by one unit, for example from pH 6.0 to 5.0, solubility of inorganic iron in the growing medium (and availability of this iron for uptake by plants) increases by a factor of 1,000. Geraniums, marigolds and certain other species are very “iron-efficient” at taking up the soluble iron and manganese into their tissue. These species evolved to grow in calcareous (low-iron, high-pH) soils and “harvest” extra iron by exuding acid or chelating agents from their roots into the soil, growing extra root hairs and other processes. When we place those plants into an iron-rich greenhouse media and fertilizer regime, they […]
February 10, 2009
Energy-Efficient Annuals: Perfecting Temps & Light
Bedding and garden plants are the largest category of floriculture crops in the United States with a wholesale value of $1.76 billion in 2007. Scheduling these crops in flower for specific market dates, at different times of the year, can be a challenge. In addition, most bedding plants are produced when energy for heating a greenhouse is a large production cost, particularly in northern climates. To optimize the greenhouse environment and produce crops as energy efficiently as possible, more information is needed on how bedding plants respond to temperature and light. Figure 1. The effects of average daily temperature on time to flower and number of flower buds in petunia. Plants were grown under a 16-hour photoperiod and an average daily light integral of 20 molâˆ™mâˆ’2âˆ™dâˆ’1. The photograph was taken four weeks after transplant from a 288-cell plug tray. During the past several years, we have performed greenhouse experiments […]
January 6, 2009
Understanding Plant Nutrition: The Series
Understanding Plant Nutrition: An Introduction Read about the basics on essential nutrients for plant growth, uptake of nutrients and pH’s effect on nutrient solubility. Nutrient Sources: Media Cation Exchange Capacity The authors take a look at the myth that cation exchange capacity is important to soilless media. Limestone and pH Why does limestone need to be added to soilless media? It’s all about pH management. Limestone, Calcium And Magnesium Limestone provides calcium and sometimes magnesium to container media. This article looks at the nutrient content of different types of limestone and how it influences calcium and magnesium levels. Irrigation Water Alkalinity & pH Water alkalinity and pH are two different measurements. This article explains the difference, how to interpret testing results and how to adjust management strategies accordingly. Irrigation Water As A Nutrient Source Water rarely contains enough primary macronutrients, but can be rich in secondary macronutrients. Check out this […]
December 16, 2008
Understanding Plant Nutrition: Managing Media EC
High fertilizer levels can be too much of a good thing, leading to excess growth, nutrient toxicity and potential runoff of nutrients into the environment. Conversely, low fertilizer levels can lead to nutrient deficiency symptoms. A basic goal for a nutrition program is to supply nutrients to the crop within an acceptable range for healthy and controlled growth. One way to ensure that nutrients are being supplied at adequate levels is with a soil test. So long as your irrigation water has salt concentrations within an acceptable range and you use a balanced fertilizer containing both macro- and micronutrients that doesn’t contain a lot of useless salts (like sodium or chloride), then there is a good relationship between the nutritional status of the root medium, and the media electrical conductivity (EC) measured using common soil testing methods (Table 1). This last article of our series discusses how to manage media […]
November 18, 2008
Universities Uniting by Paul Fisher
Writing this essay reminded me of “A Christmas Carol.” There are different futures for Extension depending which path we collectively choose to take. When the Agricultural Extension Service was created by Congress in 1914, agriculture was a dominant player in the U.S. economy. Recent trends in global food supply, biofuel and sustainability have led to a “rediscovering” of agriculture by the U.S. media. But agricultural production now represents less than 1 percent of the Gross Domestic Product (GDP) in our service-based economy. If our industry values the outreach and applied research components of Extension in the future, we need to lobby for limited resources against other worthwhile competing societal needs. In the Spanish language there is an expression–no llora, no mama–and it will take a strong collective voice (llorar) to keep Extension services as a high policy priority (la mama). I have been fortunate to work with growers in several […]
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 […]
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 […]
August 25, 2008
Understanding Plant Nutrition: Fertilizers And Micronutrients
Micronutrient (iron, manganese, zinc, copper, boron and molybdenum) nutrition is different from managing macronutrients, such as nitrogen, in three fundamental ways. First, the solubility and plant availability of micronutrients is affected by media pH to a much greater extent than is macronutrient solubility. Second, the difference between acceptable concentrations of micronutrients and concentrations that are either too low (deficiencies) or too high (toxicities) is small compared to a broader range for macronutrients. Finally, while most macronutrients are mobile within the plant, most micronutrients are immobile, and so a constant supply is needed for the duration of the crop or growth and plant appearance may be affected. In this article, we will focus on micronutrient sources, and how they are applied to a crop. Preplant Sources In soilless media, preplant sources of micronutrients are often added at mixing. In general, the sources in starter fertilizers can include both soluble forms (sulfates) […]
May 3, 2016
Migrant Farm Workers Moving Around Less Than In The Pas…
The number of farm workers who migrate and work on multiple farms during the growing season dropped from 55% in 1998 to 20% in 2009.
May 3, 2016
Hot Pink Wave-Rave Van Making Its Way To The Big Apple …
Imagine driving down the road, minding your own business, when you’re passed by two smiling, waving, happy women driving a hot-pink van that’s adorned with petunia and pansy flowers. That’s not something you see every day, but motorists in the Midwest and Northeast may catch a glimpse of the Wave-Rave van this week as Ball Horticultural Co.’s Claire Watson, Product Marketing Manager, and Katie Rotella, Marketing Communications Manager, make their way to a media tour and plant giveaway in New York City. Watson and Rotella visited Cleveland’s WOIO Channel 19 news on Tuesday morning to tell consumers about Wave Petunias and Wave Pansies, and remind them to visit their local garden centers to purchase gifts for Mother’s Day this weekend. Check out this clip on Periscope. After the morning news, the ladies stopped by to visit the Greenhouse Grower staff at Meister Media Worldwide in Willoughby, OH. Next stop: Chelsea Garden Center in Brooklyn, NY, where […]
May 3, 2016
5 Things Gardens Bloggers And Writers Learned At Califo…
For the second year in a row, the National Garden Bureau hosted five popular garden bloggers and writers on a trip to California Spring Trials. Here’s what each of them had to say about their experience.
May 2, 2016
A Fire At A New Hampshire Garden Center Challenges Spri…
Petal Pushers Farm in Laconia, NH, suffered a two-alarm fire two weeks prior to Mother's Day Weekend. It is already back up and running, but is scrambling to replace its losses.
May 2, 2016
Surprise Customers With Over-The-Top Service This Mothe…
The day before Thanksgiving a few years ago, I reluctantly pulled into Central Market’s parking lot. Central Market is a popular, high-end Texas grocery store chain, the luxury brand for the middle-of-the-road HEB stores. As expected, the parking lot was packed. There wasn’t a space in the main part of the sizable lot, so I had to park some distance away. It wasn’t a promising start to what I fully expected to be an irritating afternoon. But I was making butternut squash soup and providing wine for the holiday dinner the next day, and so I couldn’t procrastinate any longer. I was doomed to endure the busiest shopping day of the year for grocery stores. I grabbed a mini double-decker cart, resigned to cranky crowds and jostling for space in the produce aisles. I walked in and paused to figure out where I could find the butternut squash. Almost instantly, an […]
May 1, 2016
Produce Marketing Association Plans Floral Supply Chain…
The PMA Fresh Connections: Floral events will unveil new market research and trends, while offering insights into the changing landscape of floral retailing.
April 30, 2016
Registration Is Open For Farwest 2016 In Portland, OR
This year’s show takes place Aug. 25-27 and features educational sessions, nursery and retail tours, and an expansive trade show floor.
April 29, 2016
Kelly Norris: Why The Plant Collector Market Is Set To …
In his latest column for Greenhouse Grower magazine, Kelly Norris says there are more plant collectors out there than we think, which opens the way for the gift plant market to explode.
April 29, 2016
Do Customers Really Care How Plants Are Grown?
The consumer uprising against neonicotinoids has roiled the industry over the past couple of years. In June 2013, someone applied pesticide to a tree in full bloom, using the product in an off-label manner. That misapplication killed tens of thousands of bees, capturing the attention of activists. A short three years later, that activism has led to policy changes for big chains like The Home Depot and Lowe’s. Several cities and towns across the country have banned the sale of neonicotinoids. All of this made me curious. How was all the publicity affecting consumer attitudes at local garden stores? Traditionally, customers have shown little interest in how flowering plants are grown, other than they like the idea that they are from a local source. They have been much more particular about food plants than they have ornamentals. So I sent questions out to a few retailers across the country, and […]
April 28, 2016
Why Ornamental Grasses Are Great For People In Condos A…
Allan Armitage says breeders need to do a better job of making growers, brokers, and garden centers aware of better ornamental grass cultivars for the increasingly shrinking garden space.
April 28, 2016
Holistic, Integrated Approach To Pest Control Rooted In…
Greenhouse growers have been practicing integrated pest management for decades, but it’s becoming increasingly more important with the continued scrutiny of conventional pest control by a number of “regulators” — government, retail, and consumers. I just returned from Meister Media Worldwide’s Biocontrols USA 2016 Conference, in Monterey, CA, at the beginning of March this year, which served 450 attendees and 50 exhibiting supplier companies. It’s clear from the presentations and the growing attendance at this specialized event — now only in its second year — that use of biocontrols in IPM will continue to be adopted widely, as more growers get past their personal hurdles of doubt and intimidation, and embrace a new way to approach pest and disease control. Many growers think of using biocontrols as an all-or-nothing approach, but ultimately, IPM is about balance. Growers will need to continue to focus on IPM, integrating chemistry with biology, because […]
April 26, 2016
Fine Americas Offers A Digital Resource For Plant Growt…
The blog section of Fine America’s website is updated regularly, with input from both technical managers and independent researchers