Natural bark mulch
There have been a lot of questions about the use of colored mulches in the landscapes. Many individuals are concerned about the possibility of negative environmental impact from the dyes used on wood chips and pine straw. According to the Center for Agriculture, Food and the Environment (https://ag.umass.edu) the primary concern with colored landscape mulches is not the dyes used for coloring. Rather, it is about the sources of wood chips and the possibility of contamination with toxic substances.
The dyes used in coloring wood mulch are primarily of two types: carbon-based dyes and iron oxide based dyes. Iron oxide, the most commonly used dye, is simply a compound of iron and oxygen. As the compound oxidizes, iron is released to the soil but is not considered to be toxic. Dyes that are not absorbed by or adsorbed to the wood would come off with contact, especially if the mulch is wet. There are also some carbon-based dyes used on mulch. These carbon-based colorants are similar to those used in ink and cosmetics. Other dyes for mulch are vegetable-based and therefore organic. At this time, there is no evidence that the dyes used to color wood chip mulch are toxic.
Most of the wood used for making colored mulch comes from recycled wood, i.e. wood scraps, wood pallets, and wood reclaimed from construction and demolition (C&D) waste. Besides the benefits of recycling waste wood materials, the reason why these wood materials are used for colored mulches is that they are very dry and readily absorb or adsorb coloring agents.
Unfortunately, some of the recycled waste wood used for making landscape mulch products is contaminated with various chemicals, such as creosote and CCA (chromated copper arsenate). CCA is the chemical that was used in the manufacturing of pressure-treated wood.
Even though arsenic-based wood preservatives were banned in 2003, there are still plenty of CCA preserved wood being re-purposed. Sometimes wood pallets that have been used in the transport of chemical agents can become contaminated by spills of these chemicals. CCA and other toxic chemicals have been found to be contaminating soil where colored mulch made from these wood products have been applied. CCA treated wood can kill beneficial soil bacteria, beneficial insects, earthworms and young plants. It can also be harmful to people spreading this mulch and animals who dig in it.
Additionally, dyed mulches break down much slower than natural mulches. The greatest advantage to using them is to reduce the expense and time required to replenish the mulch. When wood breaks down, it requires nitrogen to do so. Colored mulch can actually rob the plants of the nitrogen they need to survive. Natural mulches retain moisture and add organic material back to the soil enabling the plants to better utilize nitrogen. Avoiding the use of colored mulches reduces the risk of contamination better than any other practices. Colored pine straw may be an alternative.
It should not be assumed that all colored mulches are contaminated. However, anyone planning to use colored mulch should become familiar with the supplier and the source of the wood used in making it. If C&D waste wood is used, it should be a red flag that there is a possibility of CCA contaminated mulch.
Certified Mulch Label
If you wish to improve the chances that the dyed mulch that you are buying is safe for humans to handle look for the MSC Certification Logo on the packaging. MSC stands for Mulch and Soil Council, whose responsibility is to certify that a mulch or soil product is free of CCA-treated wood. According to MSC’s Product Certification program, “Certified mulches and soils can be found at major retailers and garden centers across the country.” If you have concerns after contacting the supplier about the source of the wood used, contact a private environmental testing lab in your area.
While reading packaging, check the source of the product. If the supplier is a land management company rather than a processing mill it may be that mature trees are being removed and shredded. These mulches are sold as “long-lasting”, “no-float” products. They have the appearance of pine straw, but are actually finely shredded cypress from the heart of trees. These are coming from properties where the bald and white cypress trees are harvested for mulch. You can tell that it isn’t pine straw because the mulch pieces lack pine needle structures such as the fascicles and a revolute shape. While the use of these products is not contaminating, it is still depleting the environment. Mulches that are natural by-products are the most Eco-friendly.
Many gardeners plant a spring vegetable garden with a number of different vegetable types, which is excellent because a diverse and varied garden is proven to improve soil health. Intercropping is a gardening practice of growing different crops in the same field. When planting a mixture of crops in the same field year after year, it is important to rotate the location of each type of vegetable. This is a practice known as crop rotation. Intercropping and crop rotation will help reduce insect pest populations, increase beneficial insect populations, and reduce weed populations .
Including plants that pest insects don’t like to eat in a garden forces the pests work harder to find what they find palatable. Studies have found reduced whitefly numbers on squash plantings mixed with a crop of buckwheat when compared to squash planted alone. Another crop mixture that may be unintentional, but may be favorable, is a crapemyrtle stand along a garden’s edge. Crapemyrtles will attract the crapemyrtle aphid which will attract predatory insects. When the predatory insects run out of crapemyrtle aphids to eat, they will move to the vegetable garden and begin to hunt pest insects.
Squash with living mulch of buckwheat. Photo Credit: Oscar Liburd, UF/IFAS Extension
A trap crop is a plant that attracts a pest insect away from your food crops. Trap crops work best when planted at the garden’s edge, along a fence row, or in movable containers. A bare space, let’s say 5 feet or so, should be kept between trap crops and vegetable plantings. This will help keep the pests from moving desirable crops plants. When a large population of pests are found on the trap crop then it is time to spray them with insecticide, or cut the crop down and remove or destroy the debris. If trap crops are planted in containers, then it makes them much easier to remove from the garden when necessary.
Cover Crops and Green Manure
Soil organic matter can be increased by the use of green manure and cover crops. Cover crops are generally planted during the off-season, but they can be planted in between vegetable rows and tilled in at a designated time as a green manure. Both cover crops and green manure improve garden production by:
- Suppressing weeds by competing for water, light, and nutrients;
- Holding the soil in place and preventing erosion;
- Scavenging for nutrients that can be utilized in future crops;
- Reducing nematode populations;
- Providing a habitat for beneficial insects.
A mixed plot of cover crops and trap crops. Photo Credit: Matt Lollar, UF/IFAS Extension – Santa Rosa County
A number of different crops can serve as cover crops or green manure crops. Most are legumes (bean family) or grasses. A few that should be tried are:
- Sunn hemp
- Winter rye
More detailed information on cover crops and green manure can be found at this link: http://edis.ifas.ufl.edu/aa217.
If you are a regular reader of Gardening in the Panhandle, you know that this e-newsletter covers many topics related to ornamental and vegetable gardening, Florida-friendly landscaping, pest management, and lawn and garden fertility.
But did you also know that UF/IFAS Extension in the Florida Panhandle has four other E-newsletters covering topics such as Florida agriculture, wildlife and natural resources, 4-H youth, economic well-being, health and nutrition, and overall life quality for individuals and families?
These other E-Extension in the Panhandle newsletters include Panhandle Agriculture , Panhandle Outdoors, 4-H in the Panhandle, and Living Well in the Panhandle.
[notice]Additionally, UF/IFAS also has an extensive collection of publications on many of these e-newsletter topics. If you haven’t already, check out the Extension Data Information Source (EDIS) website. It is a comprehensive, single-source repository of all current UF/IFAS numbered peer-reviewed publications. Visit EDIS for a complete listing.[/notice]
As a Gardening in the Panhandle enthusiast, here is a list of horticulture and gardening related EDIS publications you might find useful:
Home Lawns and Landscapes
Soil and Fertility
The Jackson County Master Gardeners are hosting “Permaculture: An Introduction” on Saturday, April 29. Join us from 9AM to 2PM on Saturday, April 29 at the Jackson County Extension Office (2741 Penn Ave., Ste.#3, Marianna, FL) to learn the basics of permaculture. What is permaculture you might ask? Basically, it is the utilization of edible plants in your landscape to create a food forest. The workshop is $20 and includes lunch. To register or for more details please contact Matt Lollar at email@example.com, (850)482-9620, or come by the Jackson County Extension Office.
Are you an avid gardener and looking to step it up a notch? Are your gardening eyes bigger than your dinner plate? If you have ever considered selling your bounty for market, you will certainly need to do your homework! One such step you can take is to attend the UF/IFAS Panhandle Extension Team’s So You Want to be a Farmer? Workshop Series.
There’s a lot to know if you want to get into this business! This series aims to introduce new or potential farmers to innovative and environmentally safe production practices, concepts of soil and water management, integrated pest management, how to grow for a farmers’ market, and farm financial management.
Agricultural professionals are actually in high demand. There is an estimated 60,000 highly skilled jobs in agriculture available annually, but only about half of these positions are being filled by graduates in agricultural fields. Additionally, Florida’s farmers are an aging group, and there was an 8% decrease in the number of farms and 26% decrease in acres of cropland from 2002 to 2012.
Fortunately, demand has greatly increased in recent years for locally produced specialty crops, meats, and dairy. There has also been an increase in the number of direct marketing opportunities and small farmers have been able to adopt new technologies, such as season extension techniques and local online marketing, to generate more revenue on small acreages.
The UF/IFAS Extension Panhandle Agriculture Team is hosting the So You Want to be a Farmer? Workshop Series to assist beginning or novice farmers as they navigate the many challenges of getting started.
If you are interested in attending, please register on the So You Want to be a Farmer? Eventbrite page. The cost is $10 per session, with sessions at multiple locations within the east Florida Panhandle.
Please see workshop dates and further details below:
Leaf wilt may indicate more than just dry soil. Photo by Beth Bolles
Plants have specific ways of telling gardeners that there is a problem, but not all plant symptoms lead us directly to the cause. During drier conditions, we often use wilting leaves as an indicator that water is needed. This can be a reliable symptom that the soil is lacking moisture but it is not always the case. Wilting leaves and herbaceous branches actually tell us that there is not adequate water in the plant. It does not necessarily indicate lack of moisture in the soil.
There can be many reasons why water is not being absorbed by roots and moved to tissues in the plant. The obvious place to start is by checking soil moisture. If soil is powdery several inches deep around the plant, water is likely needed. However, if you ball the soil up in your hand and it holds together, there may be another reason for lack of water reaching the upper plant parts. The harder part is determining why the root system is not taking up water. Causes can be a rotted root system from too much water, a poorly developed root ball that has circling or kinked roots, and even problems in the soil such as compaction. Insects, diseases, and other pathogens can also injure root systems preventing the uptake of water.
Too much water can cause roots to decay, preventing the uptake of water. Photo by Beth Bolles
So before automatically grabbing the hose or turning on the sprinkler, do a little soil investigation to make sure that the plant wilt is really indicating lack of water in the soil. If you need help in your diagnosis, always contact your local Extension office.