Open Source Automated Irrigation System for Small Farms, Urban Farms or Specialty Crops

View the project final report

• 2016 annual report

Commodities

Practices

• Crop Production: fertigation, irrigation, water management
• Energy: energy conservation/efficiency
• Sustainable Communities: urban agriculture

Abstract

This project aims to solve multiple issues facing small and urban farmers with regards to crop irrigation. Small and urban farms often employ polyculture cropping systems. Rather than a single, large crop covering multiple acres, small and urban farms will grow several different crops in small areas. Each crop may have its own irrigation requirements – some requiring more frequent irrigation and some requiring less frequent irrigation – which presents a unique challenge that this project aims to solve.

Water conservation is an important part of any farm, big or small. Conserving water is good for the environment, your crops, and your bottom line. When sourcing water from a small body of water – a creek, river, pond or lake – there is a limited amount that can be used. When sourcing water from a municipal supply, there is a significant cost. Excessive irrigation can cause erosion, runoff, high weed pressure, and crop damage. This project aims to provide an easy method for conserving water within the proposed irrigation system.

Southeast Michigan is currently experiencing an Urban Agriculture boom. Abandoned lots in city centers are becoming small farms, families in residential areas are raising chickens and growing their own food, and small farms are popping up in rural, suburban and urban areas. Irrigation is the key to a successful crop, and getting water from its source to the plants is difficult and costly even for a small farm. This project aims to provide an economically viable and ecologically sound solution for small and urban farmers.

Proposed Solution

To solve the unique irrigation challenges of small and urban farms, and to conserve water regardless of the source, we have come up with a solution that utilizes open source hardware and software. This, combined with consumer and professional-grade irrigation components creates an economical, efficient automated irrigation system.

The core component of the system is the OpenSprinkler irrigation controller. Unlike other commercial irrigation controllers, this one is Open Source, meaning the hardware and software are both able to be modified by the user. This allows the system to be customized in any way imaginable. Another key benefit of the OpenSprinkler system is the price. The controller itself retails for $139, which is much more affordable than the commercial systems which can cost thousands.

The second component of the system is consumer-grade solenoid irrigation valves. These valves are typically used for lawn sprinkler systems; however, they can also be utilized for any irrigation method. The OpenSprinkler controller sends signals to the irrigation valve to open or close at specific time intervals. The valves can be located up to 1,500 feet away from the controller, making this an ideal solution for small farms.

The third component of the system is professional-grade drip tape. Drip tape is a plastic hose with small slits or emitters every 8” to 12”. Drip tape is extremely efficient at delivering water directly to the root system of a crop, without wasting water due to overspray, evaporation or runoff.

The combination of the Open Source OpenSprinkler irrigation controller with the consumer and professional grade components will allow small and urban farmers to customize their irrigation based on their needs. The system is affordable and efficient. It will deliver water to a diverse set of crops and can be automated.

Build Process

To make sure the system was installed by our first planting on June 1^st, I began work in late April, 2016. I purchased all of the valves, irrigation tubing, piping, irrigation controller, filters, drip tape, and other materials early so I could inventory everything and make sure I was not missing any crucial items. This was the bulk of the expenses and a detailed expense sheet is located on the budget form. I contacted the local land surveying company who originally surveyed our neighbor's land to get a report and verification of the existing property line. I wanted to make sure that I was installing my water line within my property to prevent any possible future disputes. They provided this at no charge. After verifying the property line, I made sure that the water line was more than 15 feet from the property line for a personal level of comfort. I laid out and marked the proposed waterline path with string, posts and ground-marking spray paint. I submitted a MISS DIG inquiry to verify there were no underground utilities on my proposed path. The various utility companies marked their underground items and none of them conflicted with my proposed path. Next, I contacted a local well drilling company and had them upgrade my well pump and bladder to support the irrigation requirements for the drip system that I had calculated based on manufacturer information. They also split the main line properly for me to tie in the irrigation system. Upgrading the well was an alternative solution to running electricity 1,300 feet to the back of our property to power a pump and take water from a stream. The cost of running power to the stream was double that of upgrading our well.

I installed an underground main shutoff valve for the irrigation system 5 feet from the well. This allows me to shut off the water to the irrigation system directly at the well for maintenance and winterization. I also added a blowout valve for winterization purposes. Rather than running PVC from the well to the field, I opted for polypipe and purchased a grade that was recommended by a local irrigation company. A trench was dug from the well to the back of the field to accommodate the main irrigation line. A few issues arose while digging the trench. The first issue was abandoned non-commercial electrical wires. As soon as the wires were discovered, an electrician friend was consulted to determine if they were live. They were not live so digging was resumed. The second issue was a hidden tree trunk and root system. The trench digger was unable to cut through the massive root so it was hand dug and removed with our tractor. Once the entire trench was dug, the irrigation pipe was laid in the trench and valve stand pipes were installed using a “T” connector. The standpipes were constructed out of PVC and subsequently painted white to increase their UV resistance. Along with the irrigation pipe, irrigation wire was run from our garage and followed the irrigation pipe to the back of the field. Appropriate gauge wire was used to allow for the distance needed.

An irrigation valve was installed at the top of each valve standpipe. Each irrigation valve has its own anti-siphon feature to prevent water from going through the system in reverse. This was important to maintain water safety and prevent any contaminants introduced at the drip line from entering the water supply. A backflow prevention device, as required by code and for Michigan MAEP verification purposes, was installed at the beginning of the system. Each irrigation valve was connected to the irrigation wire using outdoor waterproof splicing nuts. I further waterproofed each wire connection by wrapping it in outdoor electrical tape, enclosing each bundle of wires in a plastic bag and finally we will be installing a white, above ground valve box over each valve and standpipe in the coming year. A filter is attached to the outlet of each valve to catch debris and prevent it from clogging the downstream driptape. From the filter a smaller diameter irrigation piping was connected, also called a “sub main line”, which was then connected to drip tape at the “plot” of land within the field.

All of the vales are wired to the OpenSprinkler Open Source irrigation controller that was installed in my garage. The controller is connected wirelessly to our network and the internet. After connecting each of the irrigation wires to the unit, a test was performed. Each valve was signaled to turn on and I would verify that the valve actually opened and let water through. This system can be activated manually or using a mobile website. I was able to test the valves from my cellphone while I was in the field, between 100 and 1000 feet from the well and the irrigation controller. The commands were instantly sent to the valves each time. Within a few weeks of installing and testing the irrigation controller I had set up irrigation schedules and weather related irrigation delays. The irrigation schedule was based on each plot’s plant types and the water flow as measure at the drip tape itself. I wanted to water as infrequently as possible but still maintain proper soil moisture. 

1. Develop and test a low cost, automated irrigation system that can be shared with other small and urban farmers
2. Conserve water with the design of the irrigation system to positively impact the environment and save farmers money
3. Improve farmers’ quality of life by saving them time with an automated irrigation system.