Despite a sharp increase in costs recently, wood products remain a common landscape and garden material. They can be used for building structures, such as arbors and sheds, or for hardscapes and garden accessories, like raised vegetable garden beds or landscape timbers used for edging. Many homeowners may be confused on the safety of using certain wood products, especially around plants grown for consumption. This article hopes to explain the various options and the known safety concerns.
Raised beds are a common use of treated lumber in the garden. Credit: Molly Jameson/UF IFAS
Gardeners seem to be mostly concerned with the safety of using preserved wood products around food plants. Pressure-treated lumber is usually suggested whenever the material will be exposed to the elements and especially when in contact with the soil. Non-treated lumber, while free of any preservatives, will simply not last as long in the landscape, especially in Florida where we have a long growing season, are wet, and have lots of organisms – termites, fungus, etc. – that love to break down wood. If the wood is in direct contact with the soil, such as in a raised bed garden, you can expect non-treated lumber to last a year, maybe two, compared to three to five years with pressure-treated lumber. Wood products used for structures not in contact with soil can last significantly longer but, even then, non-treated products will need to be protected with sealers or paints to extend their longevity.
To address the safety of pressure-treated wood products, the wood products industry, and the federal government, in 2004, phased out the use of potentially hazardous chemicals used in the process – namely arsenic and chromium. Wood products preserved with these compounds were either chromated copper arsenate (CCA), ammoniacal copper arsenate (ACA), or acid copper chromate (ACC). Since 2004, much of the lumber available at hardware stores is micronized copper azole (CA) or alkaline copper quaternary ammonium (ACQ). The abbreviations for each are usually found on the little label stapled on to the lumber. So, while copper used to prevent fungal damage is still a component of pressure-treated lumber, the arsenic and chromium used to protect the wood from insect damage has been removed. Railroad ties, sometimes still in use and for sale, are much more toxic than even the older pressure-treated products because of the use of creosote and other oil-based compounds to preserve the wood.
Preserved wood products contain the preservation method on the tag stapled to the product. Credit: USDA Forest Products Lab
By removing these potentially hazardous compounds from pressure-treated wood products, gardeners should expect no adverse effects from it’s use. A Human and Ecological Risk Assessment of ACQ treated wood that was done in 2007 found exposure levels well below health benchmarks when directly contacting the wood and even with some ingestion of the material, such as contacting the wood and putting hands directly in mouth.
Even though these hazardous materials have been removed, there are still some precautions you should take when using pressure-treated lumber. These precautions include wearing a mask when cutting the lumber and not burning the lumber. This is to prevent inhalation of the chemically treated sawdust or smoke. It’s also not recommended to compost pressure-treated lumber since the chemicals can affect the microbes in your compost pile.
For those still concerned with the use of pressure-treated wood products around food crops, there are other options. In addition to using non-treated wood products or a plastic liner to separate the pressure-treated lumber from your edible garden plants. There are many other materials that can be used instead. Concrete blocks or other stone materials can be a good option. Logs from cut trees, although will rot like non-treated lumbers, can add a natural type of look to the garden.
Stone, metal, and concrete blocks are good alternatives to lumber. Credit: Mark Tancig/UF IFAS.
The February Q&A on Growing Tomatoes offered valuable tips for the home gardener to be successful with tomatoes in 2022. Below are the reference materials related to specific questions that were asked.
Let’s start out with the panels favorite tomatoes including hybrids and heirlooms.
Evan: Supersweet 100, Sungold
Larry: Amelia, Brandywine, Cherokee Purple
Sam: Better Boy, Tasti Lee, Sweethearts
Matt: Mountain Magic, Mountain Rouge, Bella Rosa
Daniel: Black cherry and Big Beef
I’m thinking of trying hydroponic gardening on a few tomato plants this year. Do you think a 50/50 mix of perlite and vermiculite would be a good approach for a soil medium? I’d like to use 5-gallon buckets and keep maintenance to a minimum.
Several years ago the Escambia County Master Gardener Volunteers added a Leopard plant, Farfugium japonicum to the office demonstration gardens. This was a new plant for me and I was immediately impressed with look and performance of this plant in a filtered shade garden.
Leopard plant’s attractive leaves and flowers make it an accent in the shade garden. Photo by Beth Bolles, UF IFAS Extension Escambia County.
Although not native to the United States, Leopard plant make an interesting addition to the Florida garden. The large green leaves can provide a tropical look throughout the entire year since it is hardy in growing zones 7-10. An added bonus of the Leopard plant are spikes of bright yellow flowers in the fall and winter months. When you use Leopard plant as a mass planting, it certainly becomes the focus in our cooler months.
Leopard plant on display in Downtown Pensacola. Photo by Beth Bolles, UF IFAS Extension Escambia County.
There are many cultivars of Leopard plant and the selections with white (‘Argenteum’) or yellow (‘Aureomaculatum’) patterns on the leaves give the plant it’s common name. There are also cultivars with curled or crinkled leaves. All plants will thrive in partial shade with some additional water when rainfall is lacking. The clumps will continue to enlarge so you can often share a piece with a friend after a few years.
Join us via Zoom on Saturday, February 12, for our Leon County Seed Library Virtual Workshop. Graphic by Molly Jameson.
Believe it or not, spring is right around the corner! For gardeners, this is the time to start thinking about our spring season garden plan and starting seeds. Many spring vegetables, such as tomatoes, benefit from an early start indoors or in a greenhouse, planted in containers. This gives them a greater chance to avoid the intense heat of summer and beat many insect and disease life cycles.
Need seeds to start your garden? Well, if you live in Leon County, you are in luck. Starting Saturday, February 12, 2022, residents of Leon County can “check out” up to three sample seed packets per month with their library card as part of Leon County’s Seed Library Program. The vegetable seeds can be checked out from any of the seven library branch locations. Leon County residents can apply for a library card online at the LeRoy Collins Leon County Public Library online card application page (https://lcpl.ent.sirsi.net/custom/web/registration/).
Here are the vegetable seed varieties that will be available starting February 12:
Mammolo Basil. Mammolo basil has an Italian aroma and a bushy, compact growth habit that is great for containers.
Maxibel Haricot Vert Beans. Maxibel Haricot Vert produces prolific beans with long, slender pods and tender texture.
Natsu Fushinari Cucumbers. Natsu Fushinari is a deep green Japanese-type of cucumber with eight-inch fruit and glossy skin. It has resistance to diseases in high heat.
Little Fingers Eggplant. Little Fingers eggplant produces clusters of tender, long, deep purple fruit that can be harvested small or large.
Pinkeye Purple Hull Southern Peas. Pinkeye Purple Hull Southern is a semi-bushy, early-season pea that produces prolific dark purple pods. It has resistance to many diseases.
Bull Nose Peppers. Bull Nose is an old pepper variety, dating back to the mid-to-late 1800s, and has medium to large, sweet fruit that is great for cooking or salads.
New Zealand Spinach-like Greens. New Zealand spinach is not a true spinach, but it loves the heat and produces succulent leaves that are excellent cooked or fresh in sandwiches.
White Scallop Squash. White Scallop is a high-yielding Native American heirloom that produces scallop-shaped fruit great for frying or baking.
Homestead 24 Tomatoes. Homestead 24 is a semi-determinate tomato that has medium to large red fruit developed for hot, humid climates, making it great for Florida gardens.
Amy’s Sugar Gem Tomatoes. Amy’s Sugar Gem grows tall, vigorous vines and produces sweet, large red cherry tomatoes.
Moon and Stars Watermelon. Resembling the night’s sky, Moon and Stars watermelon has a dark green rind with bright yellow spots. It has speckled yellow leaves and seedy, but very sweet, bright red flesh.
Whether you are located in Leon County or not, everyone is welcome to join us Saturday, February 12, from 10:00 a.m. to 12:00 p.m., for our Leon County Seed Library Virtual Workshop. Via Zoom, agents with UF/IFAS Extension Leon County will discuss spring vegetable gardening techniques and healthy eating. There will also be a live cooking demonstration showing how to prepare healthy meals and snacks at home, featuring vegetables available in the Spring 2022 Seed Library Program.
For more information about the Leon County Seed Library Virtual Workshop, please visit our Eventbrite page: https://seedlibraryworkshop2022.eventbrite.com. There is no cost to attend the workshop, but registration is required.
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.
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.
