AgNet DEMO

Category: Vegetables

  • La Nina a Concern for Fruit, Vegetable Producers

    Graphic from UGA Extension Blog.

    A La Nina weather pattern is expected to last through early spring and bring warm and dry conditions to the Southeast.

    According to the Climate and Agriculture in the Southeast blog, Pam Knox, University of Georgia Extension Agricultural Climatologist, said that the NOAA’s Climate Prediction Center predicts a 100% chance of a La Nina through the winter and better than 90% chance through early spring.

    This scenario could be gloomy news for vegetable fruit farmers, especially peach growers in Alabama, Florida and Georgia who need chill hours to make a crop for the following year. It also means pests could linger longer than desired since the lack of cold temperatures will alive them to survive longer.

    Pam Knox Comments

    Knox

    “In La Nina years, they’re much less likely to get the chill hours that they need. That’s going to be a problem for fruit producers,” Knox said.

    “Another thing is when you have warm temperatures, it’s not cold enough to kill the bugs very effectively. So you have more overwintering of bugs like whiteflies and other things that will bring disease to the plants next year. They could get an earlier start, but they’re also going to be more numerous because they’ve been able to survive the winter because of the warmer temperatures.”

    The lack of sufficient chill hours does not mean there will be zero cold weather. That’s still expected but will be overshadowed by the warmer temperatures to follow.

    “Even in La Nina years, we have some outbreaks of cold weather. It’s still winter, so we’re still going to see some of those cold outbreaks. There’s a lot of variability over time. I would definitely expect to see some colder weather. We could have some pretty big outbreaks,” Knox said.

    “It’s just that over the course of the whole winter, we’re likely to see those outbreaks punctuated by warmer spells. That’s not at all surprising. Winter is like that any way. It’s just that the whole average is a little higher. Those outbreaks come less frequently because the storm track is pushed to the north. The storm track is what controls whether we’re in the warmer air, because the warmer air is usually south of the storm track and also whether or not we’re getting rainfall because the rainfall usually happens along the storm track.”

    Prolonged Dry Spell?

    Winter is also a time when the soil moisture gets recharged due to rainfall. That’s not expected to happen this year amid La Nina, but it does appear the Southeast is in decent shape to withstand prolonged dry conditions.

    “Temperatures are lower and evaporation is lower, and plants are dormant so they’re not using a lot of water. I think from a water standpoint, at least right now, it doesn’t look too bad,” Knox said.

    According to the US Drought Monitor, southeastern counties in Georgia, as far south as Pierce and Ware, stretching as far north as Burke and Jefferson are classified as abnormally dry. The rest of Georgia, Alabama and Florida have sufficient moisture.

  • Mulch Improves Water Conservation in Vegetable Production

    Sweet onions are shown growing in Tifton, Georgia, with two types of mulch: organic (wheat straw mulch) on the left and inorganic (plastic mulch film) on the right.

    By Juan Carlos Díaz-Pérez

    For centuries, horticulturists have modified the crop microenvironment to extend the production season and enhance crop growth, yield and quality. Some of the techniques to achieve environmental modification include the use of mulches, high tunnels, greenhouses, etc.

    Mulches are widely used in both conventional and organic vegetable production. According to Wikipedia, “a mulch is a layer of material applied to the surface of soil with the goal of conserving soil moisture, improving fertility and health of the soil, and reducing weed growth.”

    Mulch may be organic (straw, leaves, cover crop residue, newspaper, wood chips, etc.) or inorganic, such as plastic film. Mulch effects on crops may vary depending on different factors.

    Factors affecting organic mulches include source of organic material (plant or animal), size of the particle, thickness of the mulch (amount applied) and age of the material. Factors affecting plastic mulch films include color, thickness, composition and permeability.

    In a vegetable crop field, soil water may be: 1) evaporated from the soil, 2) evaporated from the surface of the leaves of the crop, in a process called transpiration, 3) lost from surface runoff or 4) lost by percolation. In this article, we will focus on ways to improve soil water conservation.

    SOIL WATER EVAPORATION

    Both organic mulches and plastic mulch films act as barriers to water evaporation from the soil. These two types of mulches differ, however, in how they diminish soil water evaporation.

    In bare soil, water tends to evaporate from the soil. Soil water evaporation is proportional to the evaporative demand. Evaporation increases with increasing air and soil temperatures and decreasing relative humidity.  The rate of soil water evaporation also decreases as the soil water content decreases.

    According to the Food and Agriculture Organization of the United Nations, organic mulches may reduce soil water evaporation from 40 to 90 percent relative to bare soil. A thickness of 2 to 4 inches is effective in reducing evaporation. Soil evaporation tends to decrease with decreasing particle size of organic residues.


    Plastic mulch films are, in general, more effective in reducing soil water evaporation compared to organic mulches. Plastic mulch films differ in permeability to gases due to differences in film composition. For example, virtually impermeable film and totally impermeable film provide greater fumigant retention compared to low-density and high-density polyethylene film. With respect to soil evaporation, however, all plastic mulch films seem to be effective in conserving soil moisture.

    Physical damage or deterioration decrease the effectiveness of a plastic film to reduce soil water evaporation. Biodegradable mulches may be more prone to rapid deterioration compared to plastic mulch films.

    RAINFALL PENETRATION INTO SOIL

    Water-use efficiency increases when the crop uses rainfall water. Although organic mulches reduce soil evaporation, they allow for water penetration to the soil after a rainfall event. In fact, by reducing water flow through the soil surface and improving soil structure, organic mulches improve the water penetration to the soil and reduce soil runoff compared to bare soil.

    In contrast to organic mulches, plastic mulch films are impermeable to liquid water. Thus, they do not allow rainfall water penetration into the soil covered by the film. Rainwater that reaches the plastic film flows to the soil area between the beds and may result in soil runoff and soil erosion.

    In conclusion, both organic mulches and plastic mulch films are useful tools that help growers conserve soil moisture and increase irrigation efficiency.

  • Popular UF/IFAS Vegetable Gardening Guide Available in Spanish and as an App

    Robbie Griffin of the Family Nutrition Program harvesting leafy greens being harvested from a vegetable garden. Photo taken 02-02-20.

    November 10, 2020

    By: Brad Buck, 813-757-2224, bradbuck@ufl.edu

    With COVID-19 lingering, it might be a good time to use your green thumb to grow some vegetables in your garden. While you’re at it, you can get help from the UF/IFAS Florida Vegetable Gardening Guide — now also in Spanish — and as a downloadable web app.

    Because we’re nearing the holidays, let’s look at some vegetables you can grow in November and December throughout Florida: beets, broccoli, Brussels sprouts, carrots, collards, kale, spinach and others.

    “It’s a great time to be growing veggies in Florida,” said Sydney Park Brown, co-author of the Florida Vegetable Gardening Guide. A just-released Spanish version is also available.

    The Vegetable Gardening Guide is a collaborative effort of faculty from three UF/IFAS departments: horticultural sciences, environmental horticulture and entomology and nematology. Danielle Treadwell, associate professor of horticultural sciences and Francisco Rivera, an agent for UF/IFAS Extension Hillsborough County, spearheaded the new Spanish translation.

    The Florida Vegetable Gardening Guide was created in the 1970s by Jim Stephens, a UF/IFAS professor emeritus of horticultural sciences. It has proven to be the most popular UF/IFAS Extension document year after year. Park Brown led an effort in 1999 to substantially revise the original guide, and it’s undergone several revisions since then.

    But the app really refreshes the approach to residential vegetable-gardening efforts.

    “The Florida Fresh web app offers a modern-day way to access the information in the vegetable gardening guide,” said Park Brown, a retired UF/IFAS Extension educator. “Gardeners simply enter their zip code, and the app generates a list of the vegetables that can be planted at that time of year and in that part of the state – whether that’s north, central or south Florida.”

    The free app also offers detailed information on each vegetable links to a host of helpful publications in the UF/IFAS Electronic Data Information Source (EDIS), and refers gardeners to UF/IFAS Extension experts in their county, and lots more, Park Brown said.

    “It also lists the Florida-grown veggies and fruits that are in markets at that time of year,” Park Brown said. “This part of the app was a collaboration with the Florida Department of Agriculture and Consumer Services’ ‘Fresh from Florida’ campaign.”

  • Hurricane Eta a Threat to South Florida Vegetables

    Graphic courtesy of weather.com.

    The latest hurricane activity to threaten the United States could impact South Florida vegetable production early next week.

    According to weather.com, Hurricane Eta is threatening to approach South Florida this weekend and bring rain, high winds or a combination of both as early as Monday morning.

    Vegetable producers are feeling anxious right now, says Gene McAvoy, University of Florida Regional Vegetable Extension Agent IV Emeritus, especially since they’re at the height of the fall season.

    “We’re watching it anxiously. No matter what happens, I’m sure we’re going to get a bag of rain out of it,” McAvoy said. “Even if it doesn’t directly hit Florida and we don’t have any wind; right now it looks like it will remain a tropical storm and not a hurricane; but there’s one model that has it coming into Southeast Florida as a Category 3 (hurricane) or more.

    “We’re anxious about it because we’re at the stage now where our crops are pretty far along.”

    What’s Being Harvested?

    McAvoy said farmers are harvesting eggplants, peppers, squash, cucumbers, herbs and specialty vegetables. They’ll begin harvesting tomatoes next week.

    “It’s a little different than if they’re baby plants and you can replant rather quickly. Even if (Eta) misses Florida completely, I’m sure it’s going to result in a lot of rain, and we don’t really need any. The past several tropical systems that went through the Gulf, while they didn’t directly impact us, they’ve pumped a lot of moisture into Florida and we’ve had a lot of heavy rains and flooding,” McAvoy said.

     “We’re approaching the height of the fall season. Our big market in the fall is Thanksgiving. The next couple of weeks are critical in Florida.”

    The state’s citrus crop could also be impacted.

    “Citrus, we’re not harvesting yet, but the fruit is big enough that if you do get a lot of wind, the fruit is big enough it could start swinging around on the trees and you’ll have a lot of fruit dropping on the ground,” he added.

  • Registration Ongoing for SE Regional Fruit and Vegetable Conference

    The Southeast Regional Fruit and Vegetable Conference typically includes a trade show of hundreds of exhibitors. This year it will be held virtually amid COVID-19. Photo courtesy of the Georgia Fruit and Vegetable Growers Association.

    Registration is ongoing for the 2021 Southeast Regional Fruit and Vegetable Conference, which will be held virtually on Jan. 5 through Jan. 7, 2021.

    All events this year, including the educational sessions from university researchers and industry leaders, will take place online this year amid COVID-19 concerns. The conference will have the latest in production and crop operational information that attendees have come to expect from the SE Regional Conference.

    All educational and exhibitor content will be available for on-demand viewing until April 30 to all registered attendees.

    An All Access pass is $125 and includes access to all educational sessions, virtual trade show, poster sessions and networking events until April 30. A Trade Show Pass is free and includes admission to the virtual trade show and networking sessions but does not include access to any educational sessions. Access to the trade show floor will be available until April 30.

    You must register for the trade show to access the trade show floor.

    To register, click here.

  • Weather Could be Decisive Factor in South Georgia Farmer’s Fall Vegetable Crop

    Watson

    Weather has wreaked havoc on one South Georgia farmer’s fall vegetable production.

    Sam Watson, managing partner of Chill C Farms in Colquitt County, Georgia, said his crop has not progressed as far along as it should have by this point in the growing season. He’s concerned a potential frost could derail his plans for a productive fall season.

    “We’re Oct. 9 and not even halfway with our crop. It’s all going to depend on the weather. If we get an early frost, then we’re all going to be in trouble. It’s not going to matter what the market is because we’re not going to get our crop harvested,” Watson said. “(I’m a) little bit nervous about that. Everybody is just really late.”

    Vegetable Production

    Watson produces squash, zucchini, bell pepper, cabbage, eggplant and cucumbers in Colquitt County, Georgia, one of the leading vegetable-producing counties in the state. From the first day of planting until now, though, almost a month removed from the remnants of Hurricane Sally, weather challenges have been almost unbearable for producers like Watson.

    “Our stuff, it was stressed when we put it out because of the high heat temperatures. Then it got saturated. It wouldn’t quit raining. Then it turned off cold,” Watson said. “When it’s overcast and cloudy, bees don’t pollinate, the stuff doesn’t grow. It’s got to have sunshine. It’s been like the rest of 2020, it’s been crazy.”

    The unpredictability of the weather has delayed progress of Watson’s vegetables and has put them at risk if there is an early frost. According to weather.com, the upcoming forecast for Moultrie, Georgia includes low temperatures of 56 degrees F on Friday and 55 degrees on Saturday.

    “We should be at the halfway point and blowing and going. We just started (last week) with pepper. I should have been in pepper probably two weeks ago,” Watson said.

    “We’ve got some squash that we just started, we’ve got squash that we haven’t even started yet. We’ve got a lot of stuff that we haven’t even touched yet. They’re talking cooler weather (this week). I don’t know, we’re just going to have to see what happens.”

  • Fire Ant Control Important for Alabama Vegetable Producers

    Majumdar

    Fire ant control is essential for Alabama vegetable growers hoping to protect their crop this fall. Alabama Cooperative Extension warns producers that fire ants are known to be pests of numerous vegetable crops, including okra and potatoes.

    Ayanava Majumdar, Alabama Extension Professor, said fire ants can especially be harmful to vegetables because they’ll congregate on plants that have a heavy load of aphids. They will tend to protect aphids and other honeydew producers on vegetables. Fire ants can also damage the crops themselves and contaminate the produce.

    “I think the issue is they get on plants that get a heavy load of aphids. They follow aphids. If plants have aphids you often have the ants protecting the aphids,” Majumdar said.

    Few Management Options

    Alabama Cooperative Extension offers producers a few management options. Control fire ant mounds around or outside the vegetable production area to prevent them from moving into the garden or field. Also, manage excessive plant residue on the soil. This will help increase detection of foraging ants, provides ants fewer places to hide and make it easier to scatter bait insecticides on open ground.

    The best time to apply broadcast baits is now through Oct. 15. Mound treatments may be done year-round on warm, sunny days above 65 degrees F when the fire ants are active. Majumdar attests that the ants are active now.

    “They’re pretty active in my peanut fields. They’re pretty active in and around my vegetable fields and my garden. They’re very active,” Majumdar said.

    For more information on fire ant control, read Managing Fire Ants with Baits located on the Alabama Extension website. More information is available in Fire Ant Control: The Two-Step Method and Other Approaches on the eXtension Foundation website.

  • United Fresh Releases Fresh Facts on Retail Report

    A new report covers the increasing popularity of e-commerce and the unprecedented rise of in-home consumption triggered by COVID-19, including the continued growth of fresh fruit and vegetable sales.

    Pictured is the strawberry cultivar, Keepsake.

    United Fresh Produce Association released its Q2 2020 issue of FreshFacts on Retail this week. The report measures retail price and sales trends for the top 10 fruit and vegetable commodities and other value-added produce categories. The report says growth continues in fruit and vegetables as sales surge across categories driven by consumers seeking versatile cooking and salad staples for home meal preparation, and healthy home snack options.

    Meanwhile, packaged salads are a top-selling organic produce commodity, followed by apples and strawberries. Consumer response to value-added fruit remains muted, while value-added vegetable sales grew. Products typically consumed in group settings declined, while products that are more challenging for consumers to handle and prepare at home drove consumer interest.

    (From the National Association of Farm Broadcasters)

  • South Georgia Producers Facing Mounting Obstacles This Fall

    Kichler

    South Georgia vegetable farmers are facing their share of challenges this fall. Between heavy whitefly infestations, increased disease pressure and extreme cloud cover over the past two weeks, producers continue to deal with obstacles during this fall production season, according to Jeremy Kichler, University of Georgia Colquitt County Extension Coordinator.

    “When (Hurricane) Sally came through, we got anywhere from 5 to 6 inches. We finally dried at the end of last week,” Kichler said. “The weather started getting rainy and misty. (Wednesday) was finally the first clear day we’ve had in a while. It’s been challenging the last 10 days from a weather standpoint.”

    Sally brought intense rainfall and high winds to parts of Southwest Alabama and Northwest Florida but also excessive moisture to areas in Georgia. With little sunshine to dry fields out over the last two weeks, excessive moisture led to a flare up in certain diseases like PCAP in squash and powdery mildew.

    “Anytime you have moisture, excessive moisture, it tends to flare up things. When you have a lot of rainfall like we had, it tends to knock down adult whiteflies, but it also brings on disease problems, too,” Kichler said.

    Sally’s presence on Sept. 16, helped knock back whitefly populations, which was needed. It’s the worst whitefly outbreak since 2017.

    “Every fall we just kind of hold on tight. We’re starting to deal with these whiteflies with more timely insecticide applications. We’re getting a lot more comfortable with our management schemes with that,” Kichler said. “But it’s a still a challenge with silverleaf and some of these yellow squash and zuchinnis.”

    “We are holding our own. I think prices are pretty good right now from what I’ve been told. The silverleaf pressure has been pretty bad because of the whitefly pressure that we’ve had. It’s been challenging.”

  • Shallow Subsurface Drip Irrigation for Organic Growers

    Figure 1. Shallow subsurface drip irrigation is laid with a drip tape layer to a depth of 4 to 5 inches in organically grown lettuce.

    By Tim Coolong

    Subsurface drip irrigation (SDI) has been around for many years in a variety of different iterations. Most typically, SDI refers to a permanent drip system installed fairly deep (18 inches) and is used for irrigating agronomic crops such as corn or cotton.

    In many cases, vegetable crops are too shallowly rooted for a traditional SDI system, but some processing tomatoes are grown using SDI. However, a shallow SDI system, where drip tubing is buried at a depth of 4 to 6 inches (Figure 1), may be a tool that both conventional and organic vegetable growers can use.

    ADVANTAGES

    For organic growers, the ability to use shallow SDI offers two main advantages. The first is that crops can still be shallowly cultivated during the season without worrying about cutting drip tape. Second, having drip irrigation buried can allow for wetting of the root zone without excessive wetting of the soil surface. During dry seasons, this can reduce weed pressure (Figure 2).

    Figure 2. Acorn squash is grown with shallow subsurface drip irrigation (left) and surface drip (right). While this crop was grown conventionally with herbicide, notice the lack of grass weeds in the shallow subsurface drip irrigation plot compared to the surface drip. Earlier in the season, when this picture was taken, the surface drip-grown plants were slightly larger, but that difference subsided later in the season.

    Studies have also reported an increase in rooting depth and fertilizer use efficiency with shallow SDI. Many companies make drip tubing layers. University of Georgia (UGA) research has even used bed shapers/plastic layers to form beds and lay buried drip tube without using plastic mulch. In studies conducted with shallow SDI during a single season, no difference was seen in flow rate or clogging due to roots growing into the emitters. To keep costs low, 10-mil thick drip tubing was used since researchers only planned to use it for a single season. More permanent SDI systems use much thicker walled tubing.

    LIMITATIONS

    While shallow SDI can be a good tool for helping organic growers reduce weed pressure and improve cultivation, there are some potential limitations. UGA studies found that when comparing shallow SDI to surface drip, transplants with smaller (i.e., shallower) root balls initially grew quicker when planted into surface drip plots — particularly when weather conditions were dry and hot — promoting stress.

    Many of the studies were conducted on loamy soils. It is likely that the lack of capillary movement of moisture on sandy soils may limit the use of shallow SDI in those situations. Further, the shallow SDI system did not wet the surface adequately to germinate seeded crops.

    Lastly, although leaks were not common, rodents did chew into the buried drip tubing on occasion. Nonetheless, based on experience working with shallow SDI, it is a useful tool for organic vegetable farms.

    More details on the role of shallow SDI on weed management can be found online (see www.intechopen.com/books/weed-and-pest-control-conventional-and-new-challenges/using-irrigation-to-manage-weeds-a-focus-on-drip-irrigation) in “Using irrigation to manage weeds: A focus on drip irrigation.”