Abstract:
Hydroponic systems have existed for centuries, providing an alternative agricultural method to soil-based growing for large crop yields. Recently, hydroponic systems have attracted increased attention from the home grower market, as they provide a way to grow plants easily indoors, thereby allowing individuals living in urban environments to grow their own fresh produce. Our system would prove highly attractive to this emerging consumer market, as we plan to construct a fully automated, inexpensive, and compact hydroponic system. Using simple construction methods and easily available components, we will create a streamlined hydroponic system that will remove the hassle of manual hydroponic systems that require frequent adjustments.
Hydroponic Background:
Hydroponics is a method of growing plants using a water based mineral nutrient solution, without soil. The culture of growing plants through hydroponics has recently seen significantly growth because the controlled environment of hydroponics makes it easier to grow plants that are not traditionally grown in certain climates. Compared to soil-based growing, hydroponic systems require less water, allow for greater control of nutrient levels, result in healthier plant growth, and are easier to keep pest and disease-free. Despite these benefits, hydroponic systems require significantly more maintenance. For these reasons, the demand for automated hydroponic gardens has evolved, opening the door for a profitable business venture, particularly in providing an inexpensive system for home grower with increasingly limited living space.
The main objective of our design is to create a fully-automated, counter-top, hydroponic herb garden. A successful product would provide consumers with the ability to grow herbs in urban living environments easily and cost-effectively. Nutrient Film Technique (NFT) was the hydroponic method chosen to best fit our design goals. NFT was chosen because it has proven produce quality herbs and is the leading method used for our desired plant production. Additionally, we found it requires less total water in the system when compared to other recommended methods for common herbs.
Our primary goal is to design a system capable of automatically monitoring and maintaining pH, electrical conductivity (EC), and temperature of the nutrient solution. The solution pH affects the rate of nutrient uptake at the roots and electrical conductivity gives a measure of the dissolved solutes of the nutrient solution, thereby representing nutrient concentration. An Arduino Mega will be used to operate the control systems by interfacing with sensors, a heater, and a solid-state relay connected to peristaltic pumps. The pH is monitored using a pH probe and regulated by supplying acidic and basic solutions to the nutrient solution using a peristaltic pump. The temperature is adjusted using a heater with built-in feedback. Electrical conductivity is measured with an EC probe and adjusted by adding concentrated nutrient solution using a peristaltic pump.
Literary Research:
Internet searches have revealed that there are several hydroponic systems available on the market today. However, most of the products on the market are manually operated and lack automatic feedback systems for pH, electrical conductivity, and temperature. The devices that do have semi-automated features, such as the ability to monitor and control pH, nutrients, and temperature automatically are extremely expensive ($1,500 or more) [5].
The Modern Sprout device’s [3] overall design specifications resemble our product closest due to the device being a window sill planter. Therefore we would have a similar target audience. Although the Modern Sprout device is aesthetically pleasing, it does not monitor pH, electrical conductivity, and temperature. Rather it uses a timer to periodically supply nutrients to the plants. SuperBox [4] is another comparable device that is semi-automated. However the SuperBox is much more expensive ($795) and there is no feedback system for the nutrient solution. Other countertop designs include the Aero Pro 7 [11] and Waterworks [12] which are also more expensive with less features. Therefore our design will fill the void for an inexpensive semi-automated system with feedback.
The journal search was primarily used to determine the conditions required for the plants to grow effectively and efficiently. It was found that the nutrient concentration, temperature, pH, and lighting are the main components that need to be monitored and regulated for the proper growth of a plant [1]. There are upwards of 20 elements required for plant growth (with the concentration measured through EC). Carbon, Hydrogen, and Oxygen are naturally occurring in solution, however, Nitrogen, Potassium, Phosphorous, Calcium, Magnesium have to be manually dissolved in the nutrient solution [1]. It is important to maintain the pH of the solution because it affects how well each nutrient can pass through the root cell walls to nourish the plants [4]. Each plant has an optimal pH range, thus the pH must be measured and maintained for proper plant growth [4].
The patent search focused on the nutrient monitoring and lighting for the system. Most patents relating to LED grow lights are for arrays of LED lights of varying frequencies used in mass market growing (patent #s CN 202901994 U, WO 2012003755 A1). One method for nutrient monitoring is outlined in a patent for optical methods which monitors in near real time (patent # WO 2013022535 A2). Another system uses ion monitoring to monitor nutrients supplied in aqueous form to a plant (patent # WO 2009066991 A2).