written by: MDSomerfield•edited by: Tania Cowling•updated: 5/5/2010
A hot and humid climate, especially in the south, can present many challenges for organic gardening. Plants must be tolerant of both heat and prolonged rainfall, as well as periodic drought. Many pests and fungi thrive in hot climates and pest control is vital for organic gardens to thrive.
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Choosing Plants for Hot & Humid Conditions
There are many plants that like heat or humidity but not both; choosing the right plants for a garden is essential for its healthy survival. Tropical plants such as Chinese Hibiscus and vines like Virgin’s Bower are examples of species that do well for organic gardening in the hot humid south and other places with this climate. PJ Gartin’s book Some Like it Hot: Flowers That Thrive in Hot Humid Weather is an excellent reference for suitable plant genera.
Many organic gardeners find that switching from perennial to annual plants can produce excellent results but annual plants require more attention and a balance is always preferable. An excellent tip is to investigate hybrid varieties from local nurseries, such as the Texas 'Red Flyer'. These are non-GM crossbreeds, which often combine hardiness with aesthetics, providing a garden with color and variety while remaining tolerant of heat and insects.
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Seasonal Seed Plantation Schedule
For the organic gardener who wants to grow vegetables suited to cooler climates, implement a seasonal seed-planting schedule. Cabbages, for example, are not tolerant of hot weather and will often bolt or rot if maturing at the height of summer, yet milder weather in the winter months mean that they can often be planted during January for maturation in early to mid spring.
Researching the heat tolerance and life cycles of vegetables, and creating an appropriate seed schedule, can greatly increase the overall productivity of a vegetable patch, providing vegetable gardeners with an almost year-round supply of vegetables.
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The Benefits of Planting Trees
Planting trees can be a simple way of mitigating high temperatures and providing shade and shelter for plants that don’t do well in the heat of the summer sun. Trees can reduce surrounding temperatures by as much as 5°C by providing shade and increasing evapotranspiration, while at the same their leaves in the fall provide excellent material for organic mulch. Importantly, they also provide shade for gardeners too – gardening can be hard work in the heat of the summer.
Continue to page 2 to learn more about organic gardening in the hot humid south.
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Organic gardening in the hot humid south is challenging. Organic mulch should be used to prevent weeds, mitigate high soil temperatures and improve soil quality. Healthy plants, a variety of species and organic pesticides are all effective ways of controlling pests in an organic garden.
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Using Organic Garden Mulch
Garden mulch is one of the most important allies for an organic gardener, particularly in hot climates. Organic mulching helps to keep the soil cool in summer and increase moisture retention significantly during drought. It prevents weed growth too, improves aeration and adds new nutrients for the soil as it decomposes. Mulch helps to mitigate the extreme effects of a hot and humid climate while discouraging unwanted plant invasions.
Gardeners should be careful when obtaining ingredients for their mulch, however. Purchasing hay from farmers, for example, may seem like a good idea, but be careful that the farmer hasn't treated the hay with herbicide or other chemicals. Mulch can easily be made from grass, leaves or even weeds (once suitably cut) found in a gardener's own back yard.
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Organic Pest Control
Many of things already mentioned will encourage pest control. Plants adapted to the conditions will have better natural defenses than those which aren’t; mulch can help to protect against the invasion of weeds; trees can attract birds which feed on many pests that might otherwise attach a garden.
Plant variety is another important aspect of pest control; monocultures are more at risk from pests than gardens with a wide variety of plants. Nets and other physical barriers, such as traps, can be used to protect other vulnerable areas, while there are also some organic pesticides available for use in organic gardens, such as soft soap solutions.
Hot and humid climates create a number of challenges for organic gardeners in the south, but careful planning can go a long way to creating a successful garden. Seasonal planting and variety are essential, while trees, mulch and organic pest control techniques can all help a garden flourish.
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About Organics, “Organic Pest Control", http://www.aboutorganics.co.uk/organic_gardening/pest_control.htm
Some Like it Hot: Flowers That Thrive in Hot Humid Weather by P.J. Gartin [Wyrick & Company, Layton, 2007]
US Department of Energy, “Energy Efficiency and Renewable Energy", http://www.energysavers.gov/your_home/landscaping/index.cfm/mytopic=11910