Environmentally Friendly Florida Backyards

Introduction

In many Florida communities’ backyards are not used for living space as in northern climates. The outdoor living space is typically a screened Lanai and the space beyond the lanai frequently grass. The grass requires significant expenditure of chemicals, labor, and water. Substituting the grass with plants and trees could reduce or eliminate the cost of maintenance. It could provide a carbon neutral environment (and maybe even climate positive) and provide an opportunity to increase biodiversity. I have attempted to provide some benefits and ideas how this could be achieved to improve our environment both aesthetically and in an eco-friendly manner. I have also introduced the idea of solar dehydration which creates a more user-friendly method of handling plant material than composting or landfill.

Problem with lawns

There are currently over 5 million single family dwellings in Florida. Florida continues to build 100s of thousand additional units every year. While the yards tend to be relatively small compared to the rest of the country, they still amount to acreage. Assuming 100,000 new builds a year with a 50 by 100-foot back yard, you have 11,000 or 12,000 acres each year that could end up planted as lawn.

Lawns are not carbon neutral and in fact contribute significantly to green house gases. Lawns require weekly mowing, edging, blowing, etc. Chemicals – fertilizer, insecticide, herbicide, etc. Irrigation – minimum once a week watering. Flooding also is becoming more of a problem in Florida and the proper planting rather than lawn could help minimize flooding.

New lawns are installed with sod, at a sizable expense, and are attractive for maybe a year or two but then degrade to a carpet of miscellaneous grasses, weeds, and bare spots.

Remedy to the lawn problem

Figure 1 shows a typical Florida backyard in our development.

It is a mix of grass, weeds, and brown spots, is unattractive and we cannot run around the yard barefoot due to fire ants, nematodes, snakes, etc. This is what happens even with a weekly maintenance procedure because grass does not want to grow here.

Workers needed to maintain a lawn require a relatively low set of skills. Usually one person mows while others use blowers and trimmers to clean up the yard. Chemicals maybe applied monthly when needed and again one person with a truck and spray hose. These services are expensive and can amount to several hundred dollars per month. Water is also needed and if it is not supplied during periods of drought whatever lawn grass is present will die.

Figure 2 shows a Florida backyard planted with a variety of plants.

The plants make for a more interesting yard and if you fill the yard with plants it is easy to eliminate any need for mowing or lawn maintaince.

Maintaince of a backyard with plants depends very much on the plants. You can have a low or high maintaince yard and an opportunity to take care of it yourself or hire a knowledgable crew to provide the proper care. The primary maintaince is removal of fallen leaves and selective pruning for plant health and attractiveness. Lightning strikes in Florida are common and it is not advisable to allow the build up of dry combustable plant material on the ground especially near your home.

Plants generally do grow in squares and circles so to provide a natural landscape, plants need to be selectively pruned by hand, and depending on the plant that could be as little as once a week or maybe only once a year. You do need to think about how best to prune and maintain the yard.

There are a number of advantages with an all plant backyard. We can eliminate gas powered equipment and many chemicals. We can greatly increase the planets biodiversity. The only issue is the plant waste. Growing plants and recycling to a landfill provides a carbon neutral yard.

Yard Waste – Solar Dehydration

Composting is a good way to remove the plant waste and can be used to enrich our soil but does generate green house gases and only gives us a carbon neutral yard. A better solution to remove plant waste is to use solar dehydration. If you put plant material into a plastic or glass container and place the container in the sun in the summer you can totally dehydrate the plants in as little as 2 days. Open the container and the water will evaporate from the container in 2 more days. I have measured tempertures in a closed container of 135 degrees, although the temperture will more typically be 130 degrees. While this has been an exceptionly hot summer for much of the country, here in Florida we have afternoon highs in the low 90’s and frequently afternoon clouds. Even with these conditions a closed container will achieve a temperature of 130 degrees at least for part of the day.

Figure 3 shows the plants used for the solar dehydration experiment

Starting plants for the solar dehydration experiment. On the left is the cardboard plant, a very woody inflexible leaf, and on the right is the new growth on a golden chain tree, very flexible airy leaf. Forty grams of each were added to the containers below and the results shown after 4 days.

Figure 4 containers as exposed to the sun

Figure 5 plant material after 4 days

I did not estimate the surface area of the two materials but one can see the cardboard plant has less surface area then the golden chain tree. My thought was that the lower surface area would take longer to dehydrate. Turns out both lost water rapidly over the two day period and after drying the cardboard plant weighted 23 grams while the golden chain tree 20 grams. 50% loss for the chain tree versus 42.5% for the cardboard plant.

Next steps in this experiment would be to measure the gases generated by solar dehydration. Does the dehydration produce carbon dioxide and methane or is the by-product strictly water? Is there an optimum time and temperature to obtain the lowest emissions and maximize the drying process? What is the best way to scale up the process?

Two very different plants were used in this experiment. Another intriguing question is what plants could be grown to optimize the process. One could imagine growing plants in the spring, harvesting them in the summer and using the dehydration process to quickly remove the water and create a carbon product to be used as fossil fuel but more desirably in other ways that would not put the carbon emissions back into the atmosphere.

The dry material in both cases should lend itself to easier recycling than the original leaves. Also, this represents a significant amount of carbon that does not have to re-enter the atmosphere.

Composting takes weeks to provide a recyclable product and does not necessarily reduce greenhouse gases. Depending on the materials, it can also create undesirable odors. Solar dehydration is quick and relatively odor free.

Summary

Plants versus lawn provides a useful and low-cost solution to helping in the removal of greenhouse gases. A Florida plant backyard could at worse be carbon neutral and depending how the plant material is recycled, be beneficial in removing carbon from the atmosphere. It is an easy way to increase biodiversity. It also lends itself nicely to the idea of solar dehydration a rather painless way to remove carbon from the atmosphere. It has the potential of saving water, creating a higher skill level for landscape workers, using less chemicals in our environment, plus a priceless benefit to those who enjoy the outdoors – less noise pollution.