January 23, 2010
Understanding Plant Nutrition: Managing Multiple Species
Multiple species are often grown in the same greenhouse section, or even in the same container. Often, these species have different acceptable pH ranges and iron requirements (Table 1), which can lead to growing difficulties that affect plant quality. In this final article, we give tips on managing multiple crops in the same greenhouse. Management Tips Organize greenhouse zones so plants are grouped by similar nutritional requirements. One of the most useful groupings is based on the plant’s ability to absorb iron from the soil solution (Table 1). For example, grouping all iron-inefficient species together and away from all iron-efficient species will simplify your nutrition program because all the plants in a specific group should be able to be treated the same. Other factors to consider when grouping plants include acceptable EC levels and fertilizer requirements, light requirements (both intensity and day length) and moisture requirements. If […]
January 16, 2010
Understanding Plant Nutrition: The Complete Series
An Introduction Read about the basics on essential nutrients for plant growth, uptake of nutrients and pH’s effect on nutrient solubility. Nutrient Sources 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 article for tips on making the most […]
December 28, 2009
Understanding Plant Nutrition: Geranium Nutrition
Seed and zonal geraniums are iron-efficient crops that are prone to iron/manganese toxicity when the media-pH gets too low. Once plants show toxicity symptoms of necrotic spots and marginal burn (Figure 1), the affected leaves do not completely heal. The only options become shipping lower-quality plants–to take additional time to produce healthy new growth that will cover the older damaged foliage–or throwing plants away. Therefore, the best approach is to prevent iron/manganese toxicity (and low media-pH) from occurring. Here are some pointers for growing geraniums: Pointers – With normal fertilization practices, the acceptable pH range for iron-efficient crops like geraniums is 6.0 to 6.6. – Pre-test your root medium to determine its acceptability for growing geraniums. Often, moistening the media to near container capacity and giving it three to seven days to incubate allows the limestone a chance to react and gives a more realistic starting pH measurement than […]
November 30, 2009
Understanding Plant Nutrition: Calibrachoa
Calibrachoa are often described as a “high feed” or “high iron” requiring crop. This is not exactly true. Calibrachoa are an iron-inefficient crop and are prone to iron deficiency because they lack the ability to take up iron from the soil solution if the media pH is too high. Once iron deficiency sets in, calibrachoa will often lose vigor and become susceptible to secondary problems like overwatering or root diseases. Therefore, to succeed with calibrachoa, you need to monitor media pH regularly and take the proper corrective actions when the media pH gets too high. Here are some pointers for growing calibrachoa. Points To Consider – With normal fertilization practices, the acceptable pH range for iron-inefficient crops like calibrachoa is 5.5 to 6.2. Once the media pH increases above 6.2, iron deficiency is likely (Figure 1). – Make sure the iron deficiency symptoms are being caused by high media […]
September 16, 2009
Understanding Plant Nutrition: Stock Plant Nutrition
Nutrient management for stock plants is similar to other long-term crops. We have worked with several leading stock plant growers both in the United States and overseas over the past decade. Together, we have found the keys for success are fairly straightforward: have an organized plan that includes media and fertilizer selection, organize crops into pH or EC groups, monitor nutrition regularly and ensure adequate levels of all nutrients are present in cuttings harvested from the stock. 1. Start with a quality growing medium. Some growers consistently produce excellent quality cuttings from stock plants grown in gravel, soil or locally produced compost to save costs. However, these locally produced substrates will often present the stock producer with challenges including inconsistent mixing, excess compaction or composting, limited root growth because of lack of aeration or excessive drying, and micronutrient toxicity (often manganese, depending on the rock type) when substrate pH decreases […]
September 1, 2009
Understanding Plant Nutrition: Poinsettias
Profit margins are extremely tight for poinsettias, so minimizing shrinkage that results from crop losses is essential. If nutritional stress occurs, you will be struggling from that point onward to produce a high-quality plant for sale. Poinsettias hang around your greenhouse for several months, much longer than short-term spring crops. Therefore, a preventative approach that breaks the crop down into stages can help avoid the usual problems. Here are some pointers to consider at each stage. Pointers 1. Poinsettias have four stages in which fertilizer needs vary: propagation, initial growth, rapid growth and flowering phases. Figure 1 represents the goals in each stage. The amount of fertilizer taken up by plants varies depending on how quickly the crop is growing. 2. During propagation, avoid solutions that have a high electrical conductivity (EC) (above 0.75 mS/centimeter) or fertilizers containing phosphorus to avoid foliar damage (Figure 3). Rooting can be delayed as […]
July 24, 2009
Understanding Plant Nutrition: Environmentally Induced Plants
Most nutrients are actively taken up by the plant from the soil solution. With active uptake, the plant roots use energy to scavenge the root environment for soluble nutrients. For nutrients that are taken up actively (like nitrogen or phosphorus), their concentration in the root medium (as measured with soil tests) tends to correlate well to uptake by the plant. The exceptions to this rule are calcium and boron. Calcium and boron are taken up passively by the plant. With passive uptake, nutrients only move into the plant along with the water used for transpiration. No transpiration, no uptake, regardless of the concentration of those nutrients in the soil solution. The environment where the plants are being grown will directly affect transpiration rates, and calcium and boron uptake. The types of environments that suppress transpiration can include: – Hot, humid conditions, especially when light levels have been reduced with excess […]
June 19, 2009
Understanding Plant Nutrition: Common High Media-EC Problems
High electrical conductivity (EC) in the growing medium makes it harder for roots to take up nutrients and water–it is like trying to grow plants in sea water and can result in “salt burn” (damage to sensitive root tips) and toxicity symptoms in foliage (Figure 1). In this article, we will discuss the causes and corrections of high media-EC. What Causes High Media-EC? Media-EC is a measure of the total dissolved salt concentration contained in the soil solution and is often used as a measure of the overall nutrition status of the crop. You can think of the soil nutrient level as similar to a bank account. Our account balance (media-EC) is made up of deposits and withdrawals. The deposits are made with salts contained in the irrigation water, with water-soluble fertilizer, or by slowly soluble or controlled-release nutrients. Withdrawals are made through plant uptake or leaching. The account balance […]
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 […]
February 22, 2017
Emerging Industry Leaders Earn Business Management Cert…
Dr. Charlie Hall, Ellison Chair for International Floriculture at Texas A&M University, recently announced the graduation of the fourth cohort of the elite Executive Academy for Growth & Leadership (EAGL) program for nursery and greenhouse growers.
February 21, 2017
Learn How Drones Could Eventually Replace Bees in Polli…
Researchers in Japan are using the principle of cross-pollination in bees to make a drone that could potentially transport pollen between flowers.
February 21, 2017
Ian Baldwin: 2017 is Off to a Strong Start For Plant Re…
Many garden retailers are telling garden retail consultant Ian Baldwin that sales and the consumer’s attitude toward spending have been very strong the last two months.
February 20, 2017
5 New Varieties Shaking Up the Poinsettia Tradition
With poinsettias trending toward non-traditional colors, growers may find new opportunities to spread sales beyond the winter holidays. Here are five of the newest euphorbia varieties to hit the market that may play a role in redefining the future of the poinsettia market.
February 17, 2017
How to Keep Customers Coming Back With Top-Notch Servic…
A recent article on Forbes.com outlines seven ways organizations can take their customer service from good to great and beyond.
February 17, 2017
Proven Winners Makes Improvements to Its Retailer Certi…
Understanding the challenges of training new and seasonal staff at independent garden centers, Proven Winners says it is working to equip managers with tools to prepare their employees to better handle customers’ questions and boost their confidence in selling plants this season.
February 17, 2017
Industry Veteran Tom Foley Discusses His New Role as Vi…
Foley, a greenhouse industry veteran who was most recently with EuroAmerican Propagators, will be responsible for North American sales of WaterPulse’s patent-pending capillary mats and associated irrigation systems to nurseries and growers.
February 17, 2017
Dan and Jerry’s Greenhouse Buys Iowa-Based DeJong Green…
The acquisition will allow Dan and Jerry’s, a bedding plant grower headquartered in Minnesota, to extend its seasonal product offerings and service a new customer base with local distribution.
February 16, 2017
Pleasant View Launches Updated Website for its Savor Ed…
The site is designed to offer a friendly and informative vehicle that delivers product information in an easy-to-navigate format.
February 15, 2017
Syngenta Introduces Two New Flower Series for 2017
‘Sunfinity’ Sunflower produces multiple branches with numerous flowers that bloom all season long, while ‘Obsession Cascade’ Verbena quickly fills containers with vibrant flower patterns.
February 15, 2017
New Greenhouse Cooling System in Development for Hot-Cl…
Researchers at McGill University in Quebec have developed an alternative evaporative cooling solution for greenhouses in warm climates, and are now seeking commercial partners.
February 14, 2017
Suppliers Comment on Plant Genetics’ Fate After EuroAme…
Since the operation’s bankruptcy filing on January 23, 2017, suppliers associated with EuroAmerican Propagators have updated Greenhouse Grower on what the operation’s bankruptcy means for them – and how it will impact grower customers.