There are different types of hydroponic systems ranging from simple to high-tech. Though the most basic systems are good for beginners and are less costly, they are limited with regard to the types of plants that can be grown and the yield they can produce. High-tech systems, on the other hand, are costly and require expert knowledge with regard to setup and maintenance. Drip systems as well as Ebb and Flow Systems are the most widely used form of hydroponic growth systems because of their effectiveness and lower cost. Drip systems require the pumping of nutrient solution from a reservoir to the tops of the growing media. Nutrient solution then drips to evenly coat the growing media surface. Excess nutrient drains downward to the plants holding chamber, coating the plant roots along the way. There are two types of drip systems: recovery (recirculating) and non-recovery (non-recirculating). Recirculating drip systems are more ideal, however, since the nutrients re-circulate which saves resources and money.
Figure 1. Drip System
Ebb and Flow systems are like drip systems, but instead of dripping from the top of the plants, the water floods into chambers located at the bottom of the plants to soak the roots. A pump pushes the water (nutrient solution) through tubing from the reservoir into the main part of the system until the nutrient solution fills (floods) the system and reaches the desired height. When the water reaches the desired height, it drains back down to the reservoir and re-circulates through the system again.
Figure 2. Ebb and Flow System
Though there are pros and cons of each type of system chosen for hydroponic gardening, the system utilized is a matter of preference and depends more on the level of comfort the grower has with the system as well as cost considerations. For the pilot project, we tested both the Drip and Ebb and Flow systems to determine which one was most effective. We also compared the systems to growing the same vegetables in a traditional garden setting. The results are detailed below.
Figure 3. Production Results – Hydroponic vs. Traditional Garden
The traditional garden did yield larger bell peppers, but in smaller quantities. There was also a ten percent (10%) loss in crops when harvested due to rot. There was no loss of bell peppers grown in either of the hydroponic gardens. Because the traditional garden allowed the tomato plants to grow larger than the hydroponic system (at a rate of 2.5 – 3 times taller) more tomatoes were produced. Tomatoes tended to be larger as well. As with the bell peppers, though, a substantial amount of tomatoes (30%) were lost due to rot and bug infestation. Only a few tomatoes (0.25%) were lost in the hydroponic garden due to an ant infestation in the ebb and flow system. No tomatoes were lost in the drip system. Thus, though the traditional garden offers more room to allow for plants to grow larger and therefore produce more harvest, the amount of waste was significant enough to warrant switching to the hydroponic system, at least for smaller plants.
Figure 4. Hydroponic Peppers and Tomatoes
It is also important to note the bell peppers and tomatoes in the traditional garden were staked or caged, thus providing more support allowing for greater growth. Caging and staking will be employed in the hydroponic system to attempt to replicate similar results.
Figure 5. Graph of Produce Lost
Once accounting for the loss of produce, the hydroponic garden figures become more comparable to that of the traditional garden, though production of tomatoes in the traditional garden still remains higher.
Figure 6. Total harvest adjusted for loss
Moreover, the total area for plants grown was greater in the traditional garden. The garden plot is much larger in size (approximately 12’ x 12’). Of the 12 tomato plants planted, 9 survived. 12 bell pepper plants were planted and all survived. The ebb and flow system held 12 bell pepper plants and 12 tomato plants, but in a much smaller surface area (3’ x 3’). The drip system only held 4 bell pepper and 6 tomato plants and was even smaller (3’ x 1’). When comparing the results of the produce grown to the actual area needed to grow it, the hydroponic systems again show they are the superior choice.
In addition, when it comes to maintenance of the two types of gardens the hydroponic system yielded more pros and the traditional garden more cons.
Table 1: Pros and Cons – Hydroponic vs Traditional Garden
|Hydroponic Garden||Traditional Garden|
|No weeds||Requires more monitoring||Less expensive||Requires more land|
|Faster production of vegetables.||Expensive to set up||Larger, fuller plants||Weeds|
|Fewer Bugs||Uses electricity||Does not require electricity||Bug Infestation|
|Few, if any crop loss||More fertilizer||Less fertilizer||Crop loss|
|Less water||More expensive to germinate seeds||Less expensive to germinate seeds||More Water|
|Indoor, more water control||Water quality test kits expensive||Outdoor, less water control|
|Indoor, protected from weather||Outdoor, exposed to weather|
|Indoor, more temperature control||Difficult to determine fertilizer amounts needed|
|Outdoor, less temperature control|
As the research suggests, there was little difference in outcome between the two hydroponic systems in terms of pros and cons. The extra space of the ebb and flow system, however, allowed more room for produce to grow which produced for yield and larger produce.
Maintenance was slightly more cumbersome with the ebb and flow table. This was due to improper root maintenance which led to a clogged filter system that had to be repaired. The drip system we selected provided better protection of the filter from the roots. However, the drip system drip sticks would often dislodge, leaving the flow of water inconsistent. This was not a problem with the ebb and flow system, except for the root issue previously described. Also, if a power outage occurs, the water in the drip system immediately dissipates leaving the roots without access to water. Though the ebb and flow system eventually, too, will drain leaving no plant access to water, it takes a much longer period of time. This means unless the power outage lasts for several hours, the plants are less likely to experience distress due to a lack of water since they are more likely to remain submerged compared to those in the drip system.
The ebb and flow table was selected as the hydroponic system of choice for this project because of the amount of plants it can hold and because of the flexibility the open surface provides for growing a variety of different plants. The data collected from the pilot project also shows more produce harvested from the ebb and flow system, most likely because of the ability of the plants to grow larger due to the extra space.
CHALLENGES AND CONCERNS
This project will require the coordination of multiple disciplines. Coordination within one discipline is often a challenge and thus it is anticipated cross-discipline coordination will also pose a problem. Importantly, to move forward with the project will require involving facilities. This, too, has proven challenging.