Freeze warning is a terrifying phrase for gardeners. Cold damages your plants and may even kill them outright. Understanding how plants freeze will help you create mitigating strategies for their preservation. Informing yourself as to how freeze damages plant tissues will allow you to fortify your garden.
How do Plants lose Heat
Cold exposure happens in a couple of ways. Radiant heat loss occurs when one surface emits waves of heat into a colder surrounding environment. The surfaces of leaves and stems are not immune to this type of temperature transfer, nor is the soil in your garden beds. Frost may or may not form depending on moisture levels in the air, but cold damage will still be the result. The other main source of heat loss in gardens is through Advective freezes. These occur when cold air from the north moves south en masse resulting in colder temperatures and often increased winds. Mitigating this is a little tougher than radiant losses but not impossible
IFAS Photo
As with all things, planning is at the forefront. When designing your garden, cold hardiness should be considered. Certain plants naturally handle cold weather better than others. Utilizing native plants and those specified for your USDA hardiness zone will keep gardens alive in winter months. These tend to be acclimated for colder temperatures. Once the proper plants are selected and planted, ensure they are properly treated. Keeping your plants as healthy as possible is also critical in cold tolerance. Mulches and watering prior to a freeze event will reduce risk from radiant heat loss. The water absorbs warmth through the day and holds onto it more efficiently than dry soil would. Addition of a frost blanket will further reduce heat lost and ultimately the damage to your plants. A slightly more in-depth protection method comes from establishing microclimates in your yard. Use taller trees and windbreaks. Taller trees create a canopy that blocks heat loss to the atmosphere. Windbreaks keep the colder air away from your gardens and again prevent heat loss. None of these methods are fool proof but will help keep your gardens alive through the colder months. You may still experience damage from freezes. If this does happen, make sure your plants are watered to thaw any roots ensuring they function properly. Inspect stems by scraping a little tissue. Prune away any that shows black or brown tissue while keeping any which still looks green.
IFAS Photo
Summing up
Freezes can be devastating to your gardens. A little knowledge can go a long way toward mitigating loss. For more information on cold protection, see this Ask IFAS document, or contact your local extension agent for additional information on this and any topic regarding your gardens and more.
This month’s program focused on Gardening Myths and Home Remedies providing clarification of commonly held beliefs and insight into homemade gardening products. Below is a summary of the program with links references.
Panelists introduction:
Beth Bolles – Horticulture agent, Escambia County (Moderator)
Donna Arnold – Agriculture and Horticulture agent, Gadsden County
Mark Tancig – Horticulture agent, Leon County
Larry Williams – Horticulture agent, Okaloosa County
Dr. Adam Dale – Associate Professor at UF, Home Landscape Entomology
Dr. Dale was asked about use of home products for pest control:
He pointed out that products designed to eliminate pests are specific for that purpose. Those meant for use in the home such as Dr. Bronner’s soap are not designed as pesticides and have not been tested for that purpose. The Environmental Protection Agency (EPA) would tell you that it is technically illegal to use this product in that manner. There may be risks associated (to pets, humans, and plant life) with using these products as pesticides. Specifically spraying soap-based products on plant life is that soaps are designed to strip oils including protective oils from leaves potentially causing damage to your plants
Some products may have breakdown issues leading to phytotoxicity or may have cost/availability issues. Products may not be labeled specifically as pesticides, but all labels should be read and followed.
Your local extension agent is a good guide toward an appropriate solution for your specific issue.
Dr. Dale discussed natural pest control through plant selection:
To him, selecting plants which are less susceptible to pest is the key. For example, Yaupon holly (Ilex Vomitoria) or Dahoon holly (Ilex cassine) may be a better choice for Florida landscapes than Chinese holly (Ilex cornuta) or American holly (Ilex opaca). As a bonus, proper plant selection reduces management in your gardens.
Mark then dispelled myths surrounding using plants as mosquitos (Culicidae) repellant:
His quick answer was no, unless you were in a field of citronella (Cymbopogon nardus) and were to roll in the plants no research shows them to be effective in small scale plantings. Extracts from some of these plants do have some efficacy, but it is limited. Toward the back of the UF/IFAS Mosquito Control Guide outlines control strategies base on research. Primarily, eliminating standing water around your home including gutters which may accumulate organic matter and retain moisture is most effective. That is not to say a bird bath or rain barrel must be emptied. A similar product to Bt is Bti (Bacillus thuringiensis subsp. Israelensis) commercially sold as mosquito dunks. These are donuts or crumbles are designed to eliminate mosquito larvae in rain barrels or birdbaths thus breaking their life cycle.
Dr. Dale was asked a question on the efficacy of companion plantings:
He defined it as using plants which attract beneficial organisms. Beneficials are predators or parasitoids reducing or controlling pests in your landscape. This is not an all-encompassing solution but makes a big difference. The example cited was lawn landscapes with flowering plants nearby vs those that do not. The lawns with flowering plants have about 50% more predation and parasitism of caterpillar pests reducing pest stress.
Links were not shared during the broadcast, but here is some helpful information:
Larry was spoke concerning fall web worm (Hyphantria cunea):
He reemphasized Dr. Dale’s opinion that landscapes be planted with pest resistant varieties. Fall web worm is commonly found in many fruit, flowering, and nut trees and are easily identified by the cobwebs which begin to appear in the late summer/early autumn. This insect feeds on the leaves of these trees and tends to appear on deciduous species. This makes us worry more so than the plant does as the trees are shedding those leaves anyway. Pruning or spraying to eliminate this pest may be more detrimental to the plant than letting the insect run its course. As spring comes around and the tree puts on new leaves, they’ll appear blemish free. Better to think of them as extra Halloween decoration than treat something that isn’t causing significant damage.
There is some research showing corn gluten meal can be effective, but only as a preemergence and even then, only on some weeds. Application to growing weeds is ineffective. For larger issues it is better to work with extension agents to establish a management plan utilizing known products. Doing so may save the effort and money applied to ineffective weed control.
Beneficial nematodes are microscopic worms in soil which act as a parasitoid for soil borne insect pests. Essentially, they release a bacteria into the insect and use it to reproduce. The offspring feed on the bacteria until the host dies and the offspring is then released in the soil. They are an effective tool in IPM but have specific environmental needs to survive. They will most likely already be present in the soil, but there are commercial products containing them available.
Donna answered a question concerning lowering soil pH using sulfur.
It is a temporary fix and will be localized to the application site. Repeated applications will be needed and may cause damage to the plant life in that location. A more permanent fix is to plant appropriately for your soil conditions. These conditions may be determined through soil testing.
Larry was asked about snake repellants and whether moth balls are effective in this arena
Florida has 46 species of native snakes and only a handful are venomous. Snake identification is crucial as many have beneficial aspects. A lot of mythology surrounding snakes come from fear. Snake bites should be taken seriously but are rare, and often the person is ok post bite. There are deterrence products available, and some contain the same ingredients as moth balls. The problem with these lies in their susceptibility to environmental conditions. We get lots of rain and these chemicals wash away easily reducing their efficacy. A better method is to eliminate habitat around your home. Overgrown areas and log piles fall into this category. Keep in mind, you’ll need to clean up anything attracting other animals the snakes view as prey. Finally, inspect your home for any entrances snakes may use to enter your home and eliminate these.
Mark clarified concerns with biosolid based compost in the garden.
Biosolids are a byproduct of the wastewater treatment. At the end of the processing, there is a sludge remaining. Normally it is not recommended for any crop intended for human consumption. The Escambia County Utilities Authority (ECUA) composts this sludge other products such as yard waste to create a product that is safe for vegetable gardens. That said, it is best to apply these 120 days prior to harvest of leafy greens or 90 days for crops not touching the ground such as tomatoes as you should with all manures.
Dr. Dale was asked about vegetable oils as an alternative to petroleum based horticultural oils.
It is not a good idea to use oils other than those designed for horticulture on your plant life. It opens that plant to potential harm as the leaf cuticle and other tissues may be inhibited from their natural processes. There is no known pesticide use for these products and they are not labeled or tested for this use.
Mark spoke to using home made products using vinegar to control weeds.
There are vinegars designed for weed control, but these products are labeled and tested for this purpose. Using vinegar designed for use in the household will likely have undesired effects. Namely die off of desired landscaping for indeterminate periods. A more effective method of weed control is hand pulling.
Larry then addressed using Epsom salts in the garden.
This may be a practice passed from neighbor to neighbor. Epsom salt is made of magnesium sulfate. Both are micronutrients needed by plants for healthy growth. The neighbor who had this trick work may have been lucky in that their plants were deficient in these elements. A better way to approach this problem is through soil testing. These tests will show elemental deficiencies which may be used to establish a fertilizer program designed for your needs.
Donna was given the question as to use of eggshells in soils
The easy answer to this is yes, but use is conditional. The plant will have a hard time absorbing the calcium from eggshells in their whole form. Grinding the shells will help with this process. A better way may be to add them to your compost, but even with this, you’ll benefit from grinding them.
A question came in from facebook asking if coffee grounds acidify soil.
Mark spoke up and stated that most of the acid form coffee grounds winds up in the coffee itself, and that it is considered a “green” or nitrogenous product in composting. As most of the acidity is gone by the time they are applied to the garden, there is little effect on soil acidity but may aid soil microbiota. The key is moderation, coffee grounds should be thought of as amendments and used lightly.
Dr. Dale and Donna were asked about fire ant control
Grits and club soda are not effective tools for fire ant control according to Dr. Dale. Fire ants are an invasive species that has moved into the southern portion of the country. They are aggressive and may create large mounds and if disturbed they will sting (not bite). The most effective control for them is to use insecticide specifically designed for fire ants. Broadcast or spread these around the mound. The key here is around the mound, not on top. Bait placed on top of the mound will be treated as a disturbance and cause the colony to move rather than be eradicated. Many home made fire ant controls also encourage relocation and may cause damage to your plants. The key to ants is eliminating the queen, insecticides applied according to the label are designed for this purpose.
Gardening and pest control are surrounded with myths and home remedies. The best solution is always to find products specifically designed to resolve your specific problem. If you need help, your local extension agents are available and ready to help.
The days are getting shorter, the sun setting earlier each day, and the temperatures are beginning to dip. All the signs are there, we’ve reached autumn which means it’s time for many roadside wildflowers to begin their bloom cycle. Surely, you’ve seen them as you drive down the road, small colorful patches in the ditch or as almost blinding yellows across vast fields. The vibrant yellow in this latter example is that of goldenrod (Solidago spp.). A name attributed to many plants in Asteraceae better known as the Daisy family, they serve to feed pollinators when other plants begin to fade. Two of the most common in the panhandle are seaside goldenrod (Solidago sempervirens) and Canada goldenrod (Solidago canadensis).
Coastal Goldenrod
Seaside goldenrod will be most prevalent in the coastal counties along the panhandle. It thrives on beach dunes in tidal marshes and disturbed coastal areas. Tolerance to saline soils and sea spray allow growth in these environments. A clumping perennial, it grows to 6.6 feet clumping with a 1.6 foot spread. The flowers of this plant bloom in autumn on a spiked inflorescence as tubular disk florets. They are pollinated by several types of insects and birds. This plant was used as far back as the Roman times to treat several medical conditions.
Photo: Joshua Criss
Inland Goldenrod
Canada goldenrod is found in Florida almost exclusively in the panhandle with a few pockets as holdouts in the peninsula. Not as common along the coast, this plant prefers to take hold in ditches and open meadows. At 1-7 feet tall with it spreads via underground stems known as rhizomes. Rhizomatous plants such as these are traditionally difficult to control and may become weedy in some situations. Yellow ray style flowers present in clusters at the end of stems on drooping panicles. Pollen form this plant is often blamed for fall allergies, but does not tend to travel far on the wind making this an unlikely source. As with the seaside goldenrod, this plant was used traditionally as a medicine in ancient times.
Photo: Joshua Criss
Summing it up
Goldenrod along with many autumn blooming wild flowers may be something you’ve put very little thought into. They are proven winners in terms of late season pollinator support. Often overlooked in the home landscape, plants like goldenrod may bring a new twist to your home gardens. They require little water and fertilizer and grow well in our area. For more information on Florida wildflowers, see these Ask IFAS documents, or contact your local extension agent for additional information on this and any topic regarding your gardens and more.
Do any of the leaves change color down here in the fall? The most common answer is that there is none here in the land of evergreens. The prevalence of oaks (Quercus spp.) and pines (Pinus spp.) see to that. There is hope. Deciduous trees put on a show as the need for photosynthesis reduces. Chlorophyll production stops replaced with anthocyanins and carotenoids. As they take over, the beautiful display we all love begins. Several tree species thrive in the panhandle and have great autumn foliage. Once you know which, you’ll see a color pallet that would make DaVinci himself drool.
Tree for all seasons
Sweet gum (Liquidambar styraciflua) is a larger tree growing upwards of 75 feet tall with a 50 foot spread. The canopy has an early conical shape which evolves into an oval as the tree ages. This tree is excellent for local parks and to provide shade in your front yard. Red tinged flowers produced in spring combined with multi-shaded leaves provide interest throughout the year. However, autumn this tree comes into its own. As the days shorten and cool these leaves begin their journey to the ground by taking on shades of yellow, orange, red, or burgundy.
IFAS photograph Heather Kalaman
Panhandle Delight
A unique tree growing primarily in the Panhandle, the Florida maple (Acer floridanum) puts on an excellent autumn show. At that time of year, the leaves will change to a muted yellow or orange color. Reaching 60 feet high and 30 wide this oval canopied tree is ideal for shade or along streets. Fall is the only time you will see color changes from this tree, but in summer you’ll be treated to that classic maple leaf shape.
IFAS Photograph
An Oddity of a Tree
The bald cypress (Taxodium distichum) is a tree rife with oddity. Growing at times as high as 80 feet with a roughly 35 foot spread these trees excel in your lawn. Be wary as when grown in wet environments they develop “knees” thought to help aerate roots in standing water. Ball shaped cones are the primary reproductive organs of this tree. For the purposes of this article, we’ll focus on the color changing needles. When winter is nigh, they change from pale green to an eye catching yellow or rusty copper. One of the few deciduous conifers, the needles will fall off revealing peeled bark for winter interest.
IFAS Photograph Kathy Warner
To Sum it Up
These are but a few of the trees in north Florida known to change color in the autumn. The list is not overly exhaustive, but there are several in this category. For more information on landscape trees, see this Ask IFAS document, or contact your local extension agent for additional information on this and any topic regarding your gardens and more.
Biological control is a pillar of integrated pest management. It may seem a bit daunting the principle is simple. All things in nature have predators including insects. Biological control is simply building a conducive environment for the predators of undesired pests. One animal not often thought of in this capacity is bats. Insectivores by nature, these underutilized creatures have a big impact to your open spaces. Their steady diet of moths (Lepidoptera), beetles (Coleoptera) and flies (Diptera, which includes mosquitoes) reduce insect pressure to your gardens and landscaping.
I know what you are thinking. How effective can they possibly be? Pregnant females consume up to two thirds of their body weight through the summer months while rearing pups. Bats are small but keep in mind that these are not solitary animals. In south Texas, a single large colony consumes enough insects to save cotton farmers an estimated $741,000 per year in insecticides. That is just to illustrate the point as you won’t be able to attract huge colony. There is no reason to believe a smaller colony will not provide similar services in your gardens.
Habitat
Now that your interest is piqued, how can you attract bats to your property? Installing a bat house is the easiest way. They are typically a two foot by one foot structure holding single or multiple chambers in which bats roost. It provides shelter from predation and weather while providing a place to rear pups. Though commercially available they may be built at home with minimal cost. Place the bat house in a location with morning sun at least 12 feet off the ground. Ensure there is enough airflow around the house to keep them cool, but that the structure is watertight. Mount houses on poles next to buildings and you’ll have better success attracting residents. With everything in place, it is time to discover who will most likely be your new neighbor.
photo: Joshua Criss
The Bats of North Florida
Florida is home to 13 species of bats statewide. Of these, 11 may be found in the Panhandle but only 3 are common enough to be routinely seen. The Brazilian free-tailed bat (Tadarida brasiliensis) is the most common. Medium sized with brown fur, they have a long tail, wrinkled cheeks, and roost in man-made structures.
Photo: IFAS
Second most common are Evening bats (Nycticeius humeralis). These dark brown to yellow bats have short ears with a broad hairless muzzle. They are tolerant of other bat species often roosting in tandem with them.
Photo: IFAS
Finally, the panhandle is home to Southeastern Myotis (Myotis austroriparius). Easily the smallest of these bats, they are dull gray to brown with a lighter belly and long hairs between their toes. This species is the bat most likely to eat mosquitoes.
Photo: Jeff Gore, FWC
Finally, the panhandle is home to Southeastern Myotis (Myotis austroriparius). Easily the smallest of these bats, they are dull gray to brown with a lighter belly and long hairs between their toes. This species is the bat most likely to eat mosquitoes.
A Word of Caution
No article on wildlife would be complete without a word of caution. Bats are wild animals and should be treated as such. Never touch a bat on the ground as it most likely is not healthy. Bats do not generally cause issues but have been known to be disease vectors. Call a professional to collect the animal and never bring it into your home.
Bats can be a wonderful tool in controlling pests on your property. Creating habitat can help reduce pesticide need and cost to the homeowner. For more information on bats, see this Ask IFAS document, or contact your local extension agent for additional information on this and any topic regarding your gardens and more.
