eGRO Alerts
This page lists alerts from the current season (vol.15) and vol.14 from 2025.
For earlier seasons please click here for the archives dating back to 2012.
15.18 - Chemical Control of Weeds for Greenhouse Ornamental Production
In this e-GRO alert, growers will learn how to control weeds inside greenhouse conditions using chemical, effective methods.
15.17 - Consider the Lilies: Lily Leaf Beetle
When asked about one of their most annoying garden pests, our volunteer gardeners are unified in quickly singling out lily leaf beetle for the most earnest and precise invective. As damaging as the bright scarlet beetles are beautiful, I tend to agree.
15.16 - Pinch or Spray? Timing Branching in Spring Crops
As spring growth accelerates, early and well-timed decisions to promote branching can determine whether a crop finishes full and uniform or requires action later.
15.15 - Space Spring Crops Before Stretch Starts
As spring light and temperature increase, crop growth can shift from uniform to uneven quickly, and spacing decisions made too late often lead to reduced aesthetic quality and increased inputs.
15.14 - Downy mildew on Hellebores
Downy mildew has become an increasing problem within hellebore production. Symptoms range from speckled, blotchy purplish-black leaf spotting to purplish, vein-delimited leaf spots that resemble foliar nematode infection. You need to know the difference.
15.13 - Stay Focused on Scouting and Sanitation This Spring
Regular scouting and the use of sound cultural and sanitation practices can prevent many future problems for greenhouse and nursery producers, retailers, and ultimately, consumers
15.12 - Preventing Non-Phosphorous Related Purpling in Unrooted Cuttings
Undesirable purpling of unrooted cuttings propagated under LED supplemental lighting can be mitigated by adjusting air or root-zone temperature or the supplemental lighting intensity.
15.11 - Uniform Crops Start with Uniform Watering
Uniform irrigation is the foundation of uniform crops, and small differences in moisture management during spring production can quickly translate into measurable differences in crop growth and aesthetic quality.
15.10 - Phytotoxicity from incorrect iron chelate applications
Iron deficiencies can be common in spring bedding plant production and iron chelates are frequently applied to green crops up quickly. However, more selective applications followed by thorough foliage rinsing help avoid plant damage.
15.09 - Ironing Out Chlorosis: Selecting and Applying Iron Chelates Correctly
Iron chlorosis is most often caused by elevated substrate pH and irrigation water alkalinity that tie up iron, and this Alert outlines how to confirm the problem and choose and apply the right iron chelate for reliable correction and prevention.
15.08 - Local Cut Flowers - A Niche Market
Local cut flowers are gaining popularity among growers. This e-GRO Alert shares insights from a southeast U.S. consumers study addressing local cut flower preferences.
15.07 - Increasing Success with Tissue Culture Acclimation
Plant acclimation is a crucial step in preventing plant loss when propagating tissue culture plants.
15.06 - Rehydrating Unrooted Cuttings: A Systems Approach to Uniform Liners
Rehydrating unrooted cuttings is not a single action but a coordinated system that integrates receiving practices, holding environments, sticking workflows, humidity management, and vapor pressure control throughout the rooting process.
15.05 - Don't get burned! Always review pesticide labels before application
A grower asked me to come out and help diagnose a problem with some plugs. What caused this damage? What was the solution? How could it be avoided in the future? After investigating potential causes, we determined it was phytotoxicity from a pesticide application. But it didn't have to end like this!
15.04 - Branching Out: Controlling Branching and Apical Dominance
Producing a compact and well-branched plant is essential for success in the floriculture industry. By understanding the mechanisms of apical dominance and how cultural and chemical strategies can influence it, growers can reliably produce uniform, shelf-ready crops.
15.03 - Little Plant, Big Plans: Starting Strong
Successful spring plant production starts in the liner. It is important to promote vigorous shoot growth early to prevent production stalls and achieve the desired finish plant size and target dates.
15.02 - A Less than Ilex-cellent Situation: Strategies to Treat Spider Mite Infestation in Holly
Spider mite populations can explode under winter greenhouse conditions. Targeted integrated pest management strategies are key to recovery and ensuring crop quality.
15.01 - Herbaceous Perennial Plant Growth Regulator Guide Update
The 2026-27 Growth Regulators for Containerized Herbaceous Perennial Plants guide now available with new, research-based content focused on rooting, growth control, and updated crop recommendations for herbaceous perennial production.
14.52 - Meter Matters: Selecting a pH and EC Meter
Setting up an in-house nutrient monitoring program requires a reliable and easy-to-use pH and EC meter. Here are a few options that meet the needs of growers.
14.51 - Stem Miner Madness
Stem miners are insects with limited references in grower or scientific reports on poinsettias. Recently, in a poinsettia research study, a few scattered plants were found to have mines on the stems due to stem miners.
14.50 - A Yellow Halo: Low 2025 Sponsors Micronutrients in Poinsettia
Yellow chlorosis on recently matured leaves in the middle of the plant is a common symptom of micronutrient deficiency in poinsettia.
14.49 - Seal the Leaks and Save the Heat: Managing Cold Air Infiltration in Winter Production
Cold air infiltration is an often overlooked but expensive source of heat loss and crop stress in heated greenhouses and covered retail spaces. This Alert outlines how to recognize infiltration problems and provides practical steps to reduce drafts, protect crops, and improve heating efficiency during the production and sales season.
14.48 - Cyclamen: Targeting INSV
Impatiens necrotic spot virus (INSV) is a detrimental virus that can be easily spread by Western Flower thrips.
14.47 - Christmas Cactus: Low pH-Induced Iron Toxicity
Christmas Cacti are sensitive to low substrate pH conditions which can lead to mature phylloclades developing chlorotic blotches and necrosis
14.46 - Downy Mildew on Creeping Phlox
Downy mildew on creeping phlox can cause irregular leaf yellowing followed by leaf necrosis and browning. This disease can spread rapidly in cool and wet conditions.
14.45 - Preseason Checklist for Greenhouse Unit Heaters
A quick preseason inspection of every unit heater in production and retail greenhouses helps ensure heaters will start, run safely, and protect crops during the winter.
14.44 - Ornamental Pepper: End of Season Wrap-up
The fall ornamental pepper season is nearing the end of its cycle. This Alert contains a 2-page handout (pages 3 and 4) of problems encountered this season.
14.43 - Pansy: End of Season Wrap-up
The fall pansy season is nearing the end of its production time. This Alert contains a 2-page handout (pages 3 and 4) of problems encountered this season.
14.42 - Marigold: Fall Season Wrap-up
The production cycle for Halloween or Dia de los Muertos marigolds is complete. What were some of the issues that growers faced this season? Part of Best Management Practices is being able to recognize the primary problems that can occur and prevent them
14.41 - Preventing Late-Season Potential Poinsettia Problems
Poinsettias are a high-value fall crop that can often run into problems during the last few weeks of the production cycle. Best management practices can prevent many problems from occurring.
14.40 - Osteospermum: Lower Leaf Olive-Green Spotting
An osteospermum cultivar was exhibiting olive-green spotting on the lower leaves and eventual necrosis due to a phosphorus deficiency.
14.39 - Begonia Leaf Necrosis: A Common End-of-Season Problem
Lower leaf necrotic spotting can be problematic on Dragon Wing and large leaf begonias.
14.38 - Hungry Gerbera: A Multitude of Symptoms
Diagnosing gerbera with pale-green lower leaves, lower leaf purpling, and interveinal chlorosis of the upper and lower leaves.
14.37 - Application Timing of PGRs affects Plug Outcomes
In this Alert, we present research where we evaluated the application timing to apply Sugar Mover, an EPA-registered plant growth regulator that contains cytokinin, boron, and molybdenum, on rooting of coleus.
14.36 - Interpreting a Laboratory Water Test
The Cleanwater3 interpretation tool makes it easier for growers to understand water test results from an analytical laboratory.
14.35 - Non-chemical greenhouse weed management strategies
In this e-GRO alert, growers will learn how to control weeds inside greenhouse conditions by non-chemical, effective methods.
14.34 - Fight Mites Right
When the tough get going, use Natural Intelligence (NI), no nonsense and basic strategies to sock it to 'em.
14.33 - Ornamental Plant - Repurchase Intent
Repeat plant purchasing behavior may vary based on where customers purchase their plants (online vs in-store).
14.32 - Lace Bugs on Asteraceae
Though uncommonly encountered in greenhouse settings, growers with containerized native plants in the Asteraceae family might encounter an influx of Chrysanthemum lace bugs and the damage they cause.
14.31 - Diagnosing Calcium Deficiency of Marigold Blooms
Diagnosing calcium (Ca) disorders in flowers and fruits can be challenging due to the lack of comparative standards. Evaluation of marigold blooms for Ca was completed to fill the void.
14.30 - Magnificent Marigold Information Library
Marigolds offer wonderful spring and fall color. This Alert contains a listing and hyperlinks to cultural information available about marigolds and specific resources about producing plants for Dia de los Muertos.
14.29 - Herbicide damage to greenhouse plants and residue testing
Diagnosing herbicide symptoms can be challenging, especially when there has been no direct application near a crop. More information is usually needed about local spray applications and there are labs that can test for pesticide residue when all other avenues have been explored.
14.28 - Strategies and Guidelines for Herbicide Application During Outdoor Fall Crop Production
Effective weed management in outdoor mum and fall crop production requires proactive removal strategies, integrated weed control, and when necessary, careful herbicide application to protect surrounding sensitive plants from injury.
14.27 - Consumers Motivations for Purchasing Melons
Understanding what truly motivates a customer to select a particular melon at a farmers market is invaluable information for any grower.
14.26 - Clean Up Your Act: Readying the Greenhouse for Poinsettia Propagation
As poinsettia propagation season nears, completing a thorough sanitation plan—including proper cleaning and disinfection of the propagation environment before cuttings arrive—is essential for producing healthy transplants and ensuring a successful start to the production cycle.
14.25 - Identification and Control of Common Chickweed (Stellaria media) in Greenhouse Container Production
Chickweed and other fast-growing annuals can quickly colonize bare ground. They are often referred to as pioneer species or "weedy" plants and are one of the first steps in ecological succession.
14.24 - Botrytis in mixed containers and cell-pack flats
Large mixed plant containers can harbor Botrytis infection that may kill plants. Scout containers and cell-pack flats to catch Botrytis infection before crop loss occurs.
14.23 - Wildlife Appeal In Ornamental Plant Choices
Landscapes benefit wildlife which may be a value-added opportunity for homeowners. Here, we discuss a 2023-2024 study addressing U.S. consumers' preferences for wildlife in their landscapes.
14.22 - Keep Your Cool: Maintenance Essentials for Fan-and-Pad Cooling
Higher light intensity and air temperatures can overheat greenhouses, creating an environment that is non-conducive for plant growth.
14.21 - Dragon Wing Begonia: INSV
Symptoms Impatiens necrotic spot virus (INSV) of leaf mottling and distortion were seen on a dragon wing begonia.
14.20 - Monitoring Magnesium: Late season considerations
Magnesium is a common nutrient deficiency that can occur later in the growing season if supplemental magnesium is not supplied.
14.19 - Eats Shoots and Leaves
Although are not often pests of flowers crops, some caterpillars keep re-appearing in production. Here are some we see most often in northeast US floriculture.
14.18 - Fuchsia Rust
Fuchsia rust is not something we have seen too often, but a couple of cases have been seen in greenhouses this spring. Learn what to look for and some tips on how to manage.
14.16 - What wood cause this? Unexpected fertilizer injector problems
"If it’s not one thing, its another" culd be a motto in the greenhouse. But taking a systematic approach to solving problems will lead you to the cause!
14.15 - Powdery Mildew is out and about. Scout for it
With the extreme fluctuations in weather, conditions are right for powdery mildewdisease. Scout plants to catch the early infections.
14.14 - Heliotropium: Inconspicuous INSV
Heliotropium (Heliotropium arborescens) plants with necrotic spots on the lower leaves and stems were observed. The leaf necrosis was non-descript, but the stem necrosis made us test for viruses, which to our surprise was positive for INSV.
14.13 - Something Wicked This Way Comes
Uninvited visitors who come to stay and make pests of themselves are nothing new apparently. Each year a new pest or three turns up in our eastern Long Island, NY Insect Diagnostic Lab.
14.12 - Beware of Boron Deficiencies in Young Plants
Growers are reporting distorted growth on calibrachoa, gerbera, petunia, and pansy young plants. Given the cold and cloudy weather that most of the country experienced this winter, calcium (Ca) and boron (B) deficiencies are the first suspects. Before jumping to conclusions, learn how to differentiate between Ca and B deficiencies.
14.11 - Rooted in Success: How Branding Elevates Plant Value
Brands can generate value among customers through communicating the value proposition. Here, we discuss the importance of brands, how they influence behavior, and opportunities in the ornamental plant industry.
14.10 - Stacking without Packing- Success with Prefilling Containers
Saving time by prefilling containers and trays with substrate can be a great way to get ahead in the spring, but there are a few tips to keep in mind to avoid problems.
14.09 - Shrimp Plant: Impatiens Necrotic Spot Virus (INSV)
Shrimp plant (Justicia brandegeeana) leaves with necrotic ringspots were observed. These are typical virus symptoms.
14.08 - Avoid Holding Rooted Cuttings and Plugs Too Long
Holding rooted cuttings and plugs too long in propagation trays can lead to plant stretch, uneven growth, premature flowering, nutritional disorders, and increased pest and disease risks
14.07 - Young Plant Nutrition Tips
Dialing plant nutrition begins well before transplant day, monitoring environmental factors including moisture and temperature, fertilizer type, and fertilizer rate.
14.06 - Strong Starts for Stunning Finishes: Best Practices for Floriculture Transplants
Successful floriculture production begins with a successful transplanting season and is the foundation for producing high-quality plants.
14.05 - Proper Installation and Maintenance of a Double-Poly Greenhouse Inflation Blower
Proper installation of double-poly inflation systems requires outdoor air to reduce condensation between layers while optimizing energy efficiency and crop production.
14.04 - Black root rot is still a problem
Black root rot continues to be a problem in spring bedding plant production. Early detection, preventative fungicides, and sanitation are key to reducing disease losses.
14.03 - Best Practices for Transplanting Plugs and Liners for Spring Production
Mastering the critical steps of handling and transplanting plugs and liners is essential for maximizing crop establishment, plant uniformity, and overall greenhouse production efficiency.
14.02 - NEW - Plant Growth Regulator Guide for Annuals
The 2025 version of the Plant Growth Regulator Guide for Annuals is now available.
14.01 - Rooting for Success: Best Practices in Unrooted Cutting Propagation
Short description: Mastering the critical steps of handling and sticking unrooted cuttings is essential for maximizing propagation success, crop uniformity, and overall production efficiency in greenhouse operations.
Vol 11.04 - Three methods to check fertilizer compatibility
Mixing concentrated stock solutions is common practice in fertilization of controlled environment agriculture (CEA) crops. This article addresses three ways to check fertilizer compatibility before mixing....
Vol 11.03 - Understanding direct vs. diffuse light in the greenhouse environment
The diffuse light component in sunlight delivers light to underside of plants where direct light cannot reach. This article introduces the basic understanding of diffuse light, its benefit by improving horizontal and vertical light distribution, and ...
Vol 11.02 - Proper Plant Clip Positioning Prevents Flower and Fruit Injury in High-Wire Crops
Correct placement of plant clips and support strings is a simple, repeatable practice that prevents costly fruit damage or scarring high-wire greenhouse tomato, pepper, eggplant, cucumber, and melon crops....
Vol 11.01 - Vivipary in Greenhouse Tomatoes
Vivipary is the premature germination of tomato seeds inside the fruit and is most often associated with overmature fruit, cool storage, and plant stress. This alert highlights contributing factors in greenhouse production and practical steps to redu...
Vol 10.11 - Some Considerations in Pursuing Indoor Vertical Farm Strawberry Production
From sourcing clean planting materials to pest and disease management, from cultivar selection to crop management, this article discusses the specific requirements and unique challenges in strawberry indoor vertical farming....
Vol 10.10 - Making Financial Decisions with the HortCalculator
Leafy Greens growers face tough choices. Consumers want fresh, local produce, but pests, labor costs, and unpredictable markets make it hard to stay profitable. Deciding whether to invest in practices like biological control agents (BCAs) isn't alway...
Vol 10.06 - Lighting up strawberry: Dormancy management for maintaining productivity in winter crop production
As the day length gets shorter it is time to consider photoperiodic lighting for your greenhouse strawberry. This article describes extension lighting or night interruption lighting to improve the productivity of your strawberry plants....
Vol 10.05 - A simple tool to assess crop transpiration demand in your facility
Measurement of crop water use (transpiration) is not a trivial task, as it is affected by many different environmental factors. We have developed a simple tool that growers can use to assess crop transpiration demand via direct measurement of water e...
Vol 10.04 - A Produce Safety Primer: Selecting 2025 Sponsors Sanitizers to Control Human Pathogens
While the risk of Listeria, Salmonella, and E. coli contamination is real and documented, a grower's adherence to incorporating good agricultural practices is crucia to prevent contamination....
Vol 10.03 - Square foot weeks: quantify space-use efficiency for greens and herbs
Learn how to calculate an important metric for lettuce, herbs, and container plants....
Vol 10.02 - Heater (got you) down? Avoiding cold damage on basil
this eGRO Edible Alert will review some of the common causes of cold damage on basil int he greenhouse and how to avoid it....
Vol 10.01 - Managing Daily Light Integral to Improve Vegetable Transplant Quality
Optimizing light management is crucial for producing high-quality vegetable transplants in greenhouse environments....
Vol 9.11 - Financial Tools for Leafy Green Growers
This publication highlights the development of an online tool HortCalculator. The tool provides economic feasibility analyses of adopting integrated pest management in leafy greens production....
Vol 9.09 - UV radiation transmission of common greenhouse glazing materials
Selection of glazing materials is a critical process as it significantly affects light environment (intensity, quality, and uniformity) in addition to the structure type and construction costs. Greenhouse glazing materials have high transmission in p...
Vol 9.08 - A Primer of Artificial Intelligence for Greenhouse Control
Artificial Intelligence (AI) is disrupting industries by enabling computers to learn and perform tasks that once required human processing. In controlled environment agriculture (CEA), AI offers a potential to optimize crop management and environment...
Vol 9.07 - Disease management in edible greenhouse crops
The occurrence and severity of plant diseases within greenhouse and hydroponically produced crops is dependent on the choices growers make....
Vol 9.06 - Do Microgreens Respond to Fertilizer Concentration and Substrate Depth?
Microgreens represent a quick turn, potentially high value crop increasingly popular with consumers. In this Alert we’ll present results on how microgreens respond to fertilizer concentration and seedling depth....
Vol 9.05 - The US Market for Salad Mixes
This publication illustrates the findings from a study conducted by the author and collaborators titled “Characterizing the US Market for Salad Mixes Through the Lens of Environmental Preferences” (Ulloa et al., 2024), published in HortScience Jo...
Vol 9.04 - Do Microgreens Respond to Daily Light Integral and Carbon Dioxide Enrichment?
Microgreens are defined as a wide range of vegetable and herb seedlings that are harvested shortly after the emergence of the first true leaf. Because there are a wide diversity of species used, recommendations for cultural practices are lacking for ...
Vol 9.03 - CEA is Growing: Trends from the U.S. 2022 Census of Agriculture
Every five years the United States Department of Agriculture collects comprehensive farm level data across all agricultural commodities. The most recent Census of Agriculture based on 2022 production data was just released....
Vol 9.02 - Powdery mildew on Rosemary
An outbreak of powdery mildew was recently seen in greenhouse-grown rosemary plants. Powdery mildew management relies on scouting, removal of infected plants, environmental control, and chemical applications....
Vol 9.01 - How to grow grafted watermelon transplants
Author: Jason Hollick and Chieri Kubota (the Ohio State University) Vegetable grafting combines two plants for better plant growth and productivity. Recently we observed a fast increase in adoption of watermelon grafting in the U.S. In this article...
