Part of a Preliminary Report on:
Growing Melons in Perlite Hydroponic Cultures...
Under Protective Structures
By the University of Florida
Horticultural Sciences Department

Perlite hydroponic cultures and protective structures are used around the world to profitably produce horticultural crops. In recent research conducted by the Department of Horticultural Sciences of the University of Florida they have been proven to have great potential in Florida as important tools growers can use to increase both profits and the efficient use of their resources.

Perlite culture is the use of perlite as the medium for a soilless culture system in which nutrients and water are absorbed by the perlite and taken up by the plants as needed. Perlite culture provides a method of growing horticultural crops with a number of economic advantages. Essentially perlite hydroponics:

• eliminate the need for soil fumigants by avoiding soil-borne pathogens.
• allow precise control over the levels of nutrients crops receive during the course of the season.
• enable a grower to maximize land use by utilizing intensive production techniques such as vertical growing systems or by eliminating the need to leave ground fallow due to crop rotation.
• minimize the environmental impact of commercial growing by allowing all nutrients used in the culture system to be captured in a drainage system and to be reused in that system or in some other agricultural system.

Perlite is an excellent medium for soilless culture because it:

• has a high water holding capacity.
• has a low cation exchange rate and therefore does not significantly influence nutrient programs.
• is lightweight and easy to handle.
• can be reused and then readily disposed of by being tilled into the soil.

The basic components of a perlite cultural system include:

• polyethylene bags filled with perlite.
• a nutrient injection system.
• drip emitters which regulate the flow of nutrient solution into the bags.
• a drainage system by which leachate from the bags can be collected.

Protective structures are used worldwide to modify the environment surrounding horticultural crops. Protective structures, ranging in complexity and costs from rowcovers to glass greenhouses.

• are used to protect crops from cold temperatures allowing crops to be grown out-of-season.
• a barrier to pests attracted to a crop.
• can protect drops from rain which can negatively effect drops and fruit which are susceptible to high levels of moisture.

Walk-in tunnels are poly-covered, greenhouse-like structures with no permanent heating or cooling systems and are much less expensive than greenhouses to build and operate while providing greater cold-protection than rowcovers. Walk-in tunnels are used extensively throughout the world to produce horticultural crops in areas with climates similar to Florida’s. These tunnels generally provide a 3 to 5 C increase in plant canopy temperatures when compared to outside air temperatures.

As growers seek to maximize the use of their resources in an environmentally sound manner, perlite culture and protective structures are effective tools growers can choose to help achieve these objectives. When considering whether to use these technologies, one should do the following:

• choose a horticultural product for which a market exists or can be created.
• read the literature and identify the special challenges involved with using these systems.
• match the needs of the crop within the season one wants to grow to the capabilities of the structure to be used.
• choose a production system which allows for flexibility to grow various crops in order to be responsive to future demands.
• schedule various crops and planting dates throughout the year to optimize available space within the structure.

Once deciding to use perlite culture and/or protective structures, several basic steps should be taken in setting up and using these systems.

1. Carefully plan the nutrient solution system
   • ensure an adequate water supply by developing back-up systems and procedures
   • determine the optimum nutrient program for the particular crop being grown
2. Frequently monitor irrigation, temperature, and nutrient levels throughout the season and adjust irrigation and nutrient systems accordingly.

Additional information can be obtained from the following resources

• The Perlite Institute
• The University of Florida, Department of Horticultural Sciences

• Perlite and Hydroponics: A Possible Substitute for MeBr? ---from the USDA's Methyl Bromide Alternatives Newsletter which was written in response to this exicting research.

For more information about these uses of perlite in turf grass applications, landscaping, and/or container growing, please call or contact us at:

The Schundler Company
10 Central Street
Nahant, MA 01908
(ph)732-287-2244 (fax) 732-287-4185
www.schundler.com

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