Gardening | Gardening in the Panhandle

Chill Hours: What Are They and Why Do They Matter?

by Daniel J. Leonard | Feb 10, 2022

For being in a place known as the Sunshine State, the Panhandle has been mighty cold and dreary to start 2022! With all the recent bitterly cold weather that’s rolled through our neck of the woods over the last month or so, you may be asking yourself “Is this just a typical Panhandle winter or has it been colder than normal and what is the impact of freezing weather on my fruit trees?” The answer might surprise you!

The easiest way to measure cold and its impact on plants is through a unit of measurement known as a “chill hour”. In its simplest iteration, a chill hour is an hour of time during which the thermometer dips below 45 degrees F. These “chilling hours” are vital to agriculture and our native ecosystems because many plants, especially those that produce fruit like pears, blueberries, peaches, and even citrus, require a certain amount of chill to enter dormancy and develop flower buds for the following spring. All fruit trees have a minimum chilling requirement to initiate flowering depending on variety and too few chilling hours equals poor to no fruit the following year. Too little cold can be just as harmful as too much!

Blueberry beginning to flower after receiving adequate chill hours. Photo courtesy of Daniel Leonard.

Now that we know about chilling hours, the question remains, is this a normal winter or has it been colder than normal? The answer is neither. Based on historical average data from the UF/IFAS weather station in Marianna (a central location in the Panhandle and a good proxy for your local temperatures), as cold as we’ve been in January and early February, we’re still lagging the historical average with respect to chilling hours, and therefore to total cold temperatures. As of February 6^th, 512 chill hours had been recorded this winter. This seems like a lot until you check and see that we had 554 chill hours on the same day last year and the historic average is more than 750! Though January and February have indeed been cold this year, the chill hour graph indicates that over the last few years it’s taken longer into the calendar to achieve our first chill hour and that cold weather isn’t pushing as far into spring as it historically has.

There are many potential explanations for the warming trend in the Panhandle but regardless of your preferred theory, backyard fruit growers need to adapt to deal with the change in chill. The primary way to combat fewer chill hours is to evaluate your current fruiting plants and think about replacing high-chill varieties that no longer produce well with lower-chill varieties. If you know the variety you have, look up the number of chill hours that variety requires. If it’s an older variety that requires near the historical chill average or more, you may consider replacing it with a newer variety that requires fewer chilling hours. For example, the popular old blueberry variety ‘TifBlue’ requires 600-700 chilling hours. For most of the previous decade, we have either just barely or not reached that many chill hours, leading to a low fruit set. Replacing ‘TifBlue’ with a newer, lower chill variety like ‘Powderblue’ will probably increase your blueberry production. If you don’t know what variety of fruit tree or shrub you have, just observe the flowering period over the next spring or two. If it doesn’t flower at all or flowers sporadically and you don’t make a good fruit yield, a high chill requirement very likely could be to blame and replacing it could enhance production!

Though we’ve had an intensely cold start to 2022, if current trends continue, this wintry weather will most likely play out before we reach historic averages. That doesn’t mean you can’t grow plenty of backyard fruit, it just requires adapting to the times with lower chill varieties! To keep up with chill hour accumulation, visit http://agroclimate.org/tools/chill-hours-calculator and if you have any questions about fruiting plant variety selection, chilling hours and their effect on plants, or any other horticultural topic, contact your local UF/IFAS County Extension office! Stay warm and happy gardening!

February Gardening Dos and Don’ts

by Larry Williams | Feb 10, 2022

February can be a confusing month for North Florida gardeners. Winter isn’t over. So, don’t let spring fever cause you to make some gardening mistakes. Let’s take a look at some dos and don’ts of February gardening.

Despite colder temperatures that we can experience this month, it’s still okay to plant trees and shrubs from containers. The roots are better protected in the ground and will quickly grow outward to establish as compared to being exposed to cold temperatures above ground, confined in a container. But be cautious about planting cold sensitive tropical plants too soon while freezing weather is likely. Bare-root trees and shrubs should be in the ground promptly. This includes bare-root nut and fruit trees, pine and hardwood tree seedlings and bare-root roses. Dormant season planting allows time for establishment before hot weather arrives.

February is a good time to transplant or move trees and shrubs that are in the wrong place. Consider moving plants that require pruning to force them to “fit” into small or confined spaces. Move them to an appropriate location where they can grow to full size. Then you can plant something new and appropriately sized for replacement. Of course, they need to be reasonable in size to move.

Bush rose plant correctly pruned. Photo credit: Matt Orwat

Late February is a good time to prune overgrown shrubs such as ligustrum and holly. These plants usually respond well to severe pruning, if necessary. But remember, they will eventually regrow to their larger size. Prune to shape and thin broadleaf evergreens and deciduous flowering trees such as oleander, crape myrtle and vitex. Avoid severely pruning narrow leaf evergreens such as junipers because they have few buds on old wood from which to form new growth. Mid-February is a good time to prune bush roses, removing dead or weak canes. Leave several healthy canes and cut these back to about eighteen inches. Delay doing much pruning on early spring flowering shrubs such as azalea until shortly after they flower. Pruning these plants now will remove present flower buds before they can open. Prune deciduous fruit trees such as peach, plum and apple. Now is also the time to prune ornamental grasses such as muhly grass.

If your lawn has a history of problems with summer annual weeds such as crabgrass, apply a preemergence herbicide. This should be done February 15 to March 1 when day temperatures reach 65° to 70°F for 4 or 5 consecutive days. A second application may be needed eight weeks later. Many people fertilize their lawns too early. Wait until mid-April to fertilize to prevent lawn injury and for the most efficient use of the fertilizer.

Video: Container Planting Tips

by Beth Bolles | Feb 3, 2022

At one time or another, we have all added rocks or broken pieces of clay pots to the bottom of a container to improve drainage. This practice can actually have the opposite effect, causing the potting soil to stay too moist. Since many container-grown plants like good drainage, we end up with plant issues. Learn the method for potting up a plant that allows your soil to have good drainage with UF IFAS Extension Escambia County.

Flip My Florida Yard

by Carrie Stevenson | Feb 3, 2022

I have come to expect the unexpected when working in Extension. Photo credit: Libbie Johnson

Working in Extension has given me a lot of interesting opportunities. On the job, I’ve found myself leading kayak trips all over Florida, building a two-story bat house, and wearing a Mr. Peanut costume while talking about agriculture. But I never really imagined being featured on a home improvement reality TV show. Sure, I’ve watched my fair share of Extreme Makeover: Home Edition and Love it or List it, but those were just entertaining ways to pass the time and maybe get some ideas for my own house.

Then, a few months ago our office was contacted by the producers of a show called Flip My Florida Yard, to inform us they would be in Escambia County to film an episode of the show for the Discover Florida channel. As part of the effort, they’d need a local Extension agent to go on a site visit, help review the landscape design, and talk about Florida friendly landscaping principles on air. Based on my prior experience as a Florida Yards & Neighborhoods agent (and our horticulture agent being swamped with Master Gardener training), I got the reality TV job.

Florida-friendly landscapes use water and fertilizer appropriately, include wildlife-friendly vegetation, and reduce stormwater runoff. Photo credit: Carrie Stevenson, UF IFAS Extension

Part education and part entertainment, the show’s premise is similar to most home remodeling shows. A couple or family wishing to improve their current home shares their hopes with the remodelers, the homeowners are sent away for a day, and upon their return they are surprised with a brand-new look.

The twist with Flip My Florida Yard is that the landscapes in need of improvement are redesigned with Florida-friendly principles in mind. During each episode, Extension agents, IFAS researchers, and landscape designers are interviewed about concepts like using mulch and compost, proper irrigation, or “right plant, right place” choices based on soil type and sunlight availability. Last season, the crew was in Panama City to help a family restore their yard after damage from Hurricane Michael. For our Escambia County program, we will focus on appropriate fertilization, managing stormwater, protecting the waterfront, and providing wildlife habitat.

The “Flip My Florida Yard” program features Florida homeowners getting a Florida-friendly landscape renovation. The show is available online and through several streaming services.

In late December I was interviewed by the show’s producers, and we spent a full day renovating a local backyard. The challenging, steeply sloping backyard was given some really nice amenities, including a rain barrel, a seating area, and wildlife attractants. Our local episode should air in March or April. In the meantime, all the past episodes are available for viewing on the Discover Florida Channel. The channel can be accessed via a free online account, or through several streaming services like Roku, Apple TV, and Amazon Fire. Flip My Florida Yard is a creative partnership between the Department of Environmental Protection/Florida State Parks and the state level UF IFAS Extension Florida Friendly Landscaping Program, so even the commercial breaks cover environmentally friendly messages and scenic views of state parks. Check it out—you might get some helpful ideas or even become the next homeowner featured!

Winter Planting and Spring Preparing

by Ashley Stonecipher | Jan 26, 2022

Violas. Photo Credit: University of Florida/IFAS Extension

It is freezing cold this week and hard to believe that we are already talking about “What to Plant” and “What to Do” to get started early. In North Florida there are cool-season annuals that can be planted now. The list includes pansies, violas, petunias, and snapdragons. As we are coming to the end of January it is time to plant crinum, agapanthus and gloriosa lily bulbs. Make sure to mulch these areas after planting to protect them from the cold temperatures. This is also the month to plant camellias, which these come in many colors and forms that your local nurseries will carry this time of year. If you haven’t planted all your cool season crops there is still time to do that now such as broccoli, kale, carrots, and lettuce. Irish potatoes can be planted now as well.

Now you might be asking “What can I do?”. January is a great time to prune non-spring flowering shrubs and trees to improve their form. This is a good time to plant deciduous fruit trees, this will give their roots time to develop before the warmer spring temperatures. Since existing trees are dormant, it is a good time to prune and fertilize them. When the temperatures are near freezing many of the tender plants will need to be covered to minimize damage. It’s a good time to plant a tree. Hurricane-resistant trees include live oaks, bald cypress, cabbage palms, and southern magnolias. It’s time to remove those dead spent seed pods on your crape myrtles and removing any crossing branches and twiggy growth will improve the appearance and the form of the plant.

Potatoes planted in mid-February were ready to harvest in mid-May in Bay County. Photo: Vicki Evans, UF/IFAS Master Gardener of the plant.

As we go into February it will soon be time to apply a preemergence weed killer to your lawns to prevent warm-season weeds. Temperatures must rise to 65°F for 4 to 5 consecutive days before you do a preemergence application and make sure you are not using a weed and feed fertilizer. Citrus and other fruit trees can be fertilized at this time. The amount and frequency will depend on the age and type of fruit tree you are growing. Avoid pruning Citrus until spring to avoid any injury since cold temperatures are still possible. It is time to prune those roses this month to remove damaged canes and improve the overall form. After the pruning is complete you can fertilize and apply a fresh layer of mulch. They should begin blooming within 8 to 9 weeks after being pruned.

Dianthus, pansies, violas, and dusty millers are annuals that can take a chill and should be planted in February. You can continue to plant crinum and agapanthus this month and add on amaryllis and rain lily bulbs as well. If it has been dry make sure to provide plenty of water for the bulbs to establish and continue to protect them from the cold by adding mulch. Trees and shrubs will begin to bloom this month including red maples and star magnolias. Continue planting potatoes throughout the month and towards the end of February warm-season crops like tomatoes and pepper can be planted but be prepared to protect them from any late frosts.

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