With the development of plastics, hydroponics took another large step forward. If there is one single factor that could be credited with making the hydroponics industry the success it is today, that factor is plastics.
As mentioned earlier, one of the most pressing problems encountered everywhere was the constant leaching of detrimental elements into the solution from concrete, rooting media, and other materials. With the advent of fiberglass and such plastics as the different types of vinyl, polyethelene film, and the many kinds of plastic pipe, this problem was virtually eliminated. In the better producing systems being built in the world today plastics are used throughout, and other than a few isolated bronze valves, there is absolutely no metal. Even the pumps are epoxy coated. Using these types of materials, along with an inert material as a rooting medium, the grower is well on his way to success.
Plastics freed growers from the costly construction associated with the concrete beds and tanks previously used. Beds are scraped out of the underlying medium and simply lined with a heavy vinyl (20mil), then filled with the growing medium. With the development of suitable pumps, time clocks, plastic plumbing, solenoid valves and other equipment, the entire hydroponic system can now be automated, or even computerized, reducing both capital and operational costs.
A basic premise to keep in mind about hydroponics is its simplicity. After the wheel was invented, I am sure many were confused and thought it complicated. That was because they could not get their minds off all the work the wheel replaced. This is the way it is with hydroponics. Once you conquer the idea there must be more to it than this, and forget about the work it eliminates, you too will agree: It is simple!
Another important breakthrough in hydroponics was the development of a completely balanced plant food. Work in this area is still continuing, but there are many ready made formulas available. Most of them are good, but very few, if any, will work consistently without the use of various addatives at different stages of the crop. There are also many formulas available that can be mixed by anyone, but the average grower is far better off using one fo the many commercial formulas.
In addition to the progress rate through the use of plastics and the steady increase in production because of improved nutrient mixes, another factor of tremendous importance to the future of the industry was the development of better hardware for control of the environment in greenhouses.
Initially, nearly all fo the early greenhouses were steam heated, and the cost of this equipment virtually barred the small grower from entering this field. With the development of forced-draft heaters that used oil or gas, however, it became possible to build much smaller units, and the advent of LP gas, such as butane and propane, made possible the location of greenhouses in almost any area.
Constant improvements in these heating systems, particularly the introduction of high-velocity fans and the convection tube method of circulating warm air throughout a building, gave the grower better temperature control in the greenhouse. For commercial operations in larger greenhouses, however, a boiler system using steam or hot water remained the most economical. It gave the grower wide latitude in the choice of fuels. There has also been continuous improvements in techniques and equipment for cooling any size greenhouse.
In addition to better environmental control, the use of new materials such as polyethelene, poly-vinyl films, and translucent fiberglass panels introduced completely new methods of low cost greenhouse contruction. They give the builder a wide choice of material for covering any size unit and also made possible many new shapes, sizes, and configurations.
Some of these materials will last only one season; others are guaranteed for 20 years, against clouding, that causes light loss and against shattering from hail; despite damage to the cover, there was little or no damage to the crop. Had a light film or glass been used, however, both the crop and cover would have been completely lost. The films are good for temporary or semi-temporary cover. Many of these materials also gave light diffusion that is beneficial to most plants.
The combination of environmental control and improved hydroponic systems has largely been responsible for the growth of the industry over the past twenty years, and there can be no question that hydroponics will play a big part in feeding the world in the future.