Hydroponic growing is growing a plant without using soil – usually in an inert substance like rock wool or perlite, which hold the roots for easy water and nutrient absorption. Hydroponics systems back several hundred years, and there is evidence that ancient civilizations grew plants in water. Nutrients are vital to hydroponic success: there are sixteen essential elements that a plant needs to grow, and the right balance of these nutrients must be maintained for each specific variety of plants.
Equally as important as nutrition are the factors of light, temperature (heating and cooling), and carbon dioxide. Insects play a key role in pollination and pest management. When you combine all of these factors, you create the controlled environment necessary for a hydroponic greenhouse.
There are many different hydroponic growing systems and each has its own advantages and disadvantages. A closer look at some of the systems will give you a bit of insight into the fascinating world of hydroponics.
- Deep Water Culture
In a deep water culture system, the plant is held in place by a small amount of inert medium (usually gravel or clay pebbles). However, the vast majority of the plant’s roots do not grow in the medium, but, rather, dangle down into the container where they are submersed in the nutrient solution. These systems are great because they are easy to build and can produce quick, vigorous growth. The biggest drawback of deep water culture systems is how susceptible they are to temperature changes.
Since the roots are submersed in the solution, the temperature of that solution will greatly affect the way the plant’s roots can receive oxygen. When temperatures are too warm, the plant’s roots will not receive the oxygen they require and they will become susceptible to pathogens. For this reason, deep water culture should only be used by greenhouse growers in cooler climates or growers who have invested in cooling devices, such as water chillers or air conditioners. Without a cooling device, a grower may have a difficult time keeping the system’s temperature in the desired range.
- Drip Irrigation
In a drip irrigation system, the nutrient solution is delivered to each plant via a drip stake or drip line emitter. The individual plant modules will vary from system to system, but, generally, drip gardeners use standard potting containers. The medium for the containers can be any sort of inert medium or even soil if the grower wishes to have a more hybrid hydroponic/soil system. Top-drip systems can be set up as a recirculating system or a run-to-waste system. Recirculating drip systems will need a reservoir for holding the nutrient solution and the reservoir will need to be aerated. A timer is needed to trigger the pump for feeding intervals. The duration will fluctuate depending on the crop being grown and the particular stage of growth. Although drip systems are a little more expensive to start up than a deep water culture system, they fare much better at higher temperatures. Drip systems are also the preferred hydroponic system of commercial tomato growers.
The traditional greenhouse grower is comfortable producing bedding plants, flowering potted plants, potted foliage plants and cut flowers. The regimen most familiar to seasoned greenhouse devotees can be expensive and often financially challenging. Many of these growers are now faced with increased competition and the rising cost of labor, energy and crop inputs. To maximize return on their investment, growers are gradually diversifying their crops to include hydroponic vegetables learning quickly that locally produced lettuce, tomatoes, cucumbers, and peppers are in high demand.
Sustainably and the locally grown food is a very hot topic. Many growers have realized that fruits and vegetables, grown year-round in greenhouses, are a good investment.
Big-budget consumers, like school districts and restaurant chains, are making the switch to locally grown foods. States are increasing the percentage of fresh produce that makes up school lunches, helping students and faculty lead healthier lifestyles. Individual consumers are more interested in where their food comes from, and this interest will continue to grow and drive demand further upwards. With transportation costs skyrocketing and food safety concerns at an all-time high, hauling food by truck, ship, and air has become prohibitive. With all these compounding matters, it should be obvious that local is the way to go, but produce managers and buyers have somehow not been able to meet the increased demand for locally grown foods.
The Hydroponic Advantage
These changing trends have increased opportunities for greenhouse growers to significantly increase sales and profits using their existing facilities operating year round. But the hesitance with which growers are adding vegetables and fruit to their offerings is baffling. A pre-existing greenhouse can easily accommodate hydroponic growing with few adjustments.
Today’s hydroponic growing methods have proven to make growing easier and more reliable than field growing. Labor costs and crop input costs are lower, and quality is much higher. Hydroponic and greenhouse yields are commonly ten times that of the field yield for a one-crop-per-year harvest. In some cases, hydroponic and greenhouse yields have achieved one hundred times the field yield of Bibb lettuce. One grower in California grows 3.2 million heads per acre per year! Soilless hydroponic growing offers savvy greenhouse growers the opportunity to increase the sales per square foot of their facilities by five or more times. To learn more about hydroponic growing, Dr. Lynette Morgan’s book Hydroponic Lettuce Production and Dr. Howard M. Resh’s Hydroponic Food Production (the 7th edition is out in August) are good places to start.
Converting greenhouses from housing traditional plants to edible production is now very easy and low in cost. Growers can convert their low- to medium-technology greenhouses to hydroponics without having to invest a substantial amount of money in a new greenhouse. Most growers, with some research and persistence, can tackle the project on their own.
A growing number of colleges and vocational schools have agricultural departments and curriculums catering to students with futures as passionate, qualified growers. Banks and other leading institutions that champion the locally produced food movement will stand and support this new generation of growers. Many growers, new and old, have received low-interest financing for their projects by said institutions that understand the economics behind these endeavors. From the introduction of corporate CSA programs to businesses providing locally grown food in lunchrooms, meetings, and conferences, it is clear that growers are quickly gaining larger allies outside the agricultural industry.
The future is bright for growers that choose to grow hydroponically in existing greenhouses. Low-cost investment and nearly unlimited market opportunities have spurred perceptive growers to make the smart move to growing more edibles as a percentage of their total growing area. Will you make the same choice?
Hope this will help and see you untill next time 🙂