Despite the melancholy lackluster feel of this blog, I normally am a rather chipper person. I don’t get offended easily, and there aren’t many things that I don’t like. As I venture more into farming, I have found that the intensity of my emotions has increased, both love for things and utter hatred. This year, I learned to hate one thing in particular: irrigation.
San Diego has a fantastic climate. Warm, sunny, great for growing crops. The down side is that we have a terrible drought, and I did not want to be doing overhead irrigation on a half-acre. The land itself is slightly sloped and while it is flat in general, there are some ups and downs. Choosing an irrigation scheme that would work on this was not straight forward.
I had ruled out overhead simply because of climate, so the next option was deciding what type of drip line to use. I could run polyvinal tubing and insert emitters; I could have tubing with built in emitters; or I could use drip tape.
Analyzing Irrigation Options
Tubing with attached emitters would be a non-starter because I did not want to deal with maneuvering around emitters and repairing line as emitters got torn out.
Drip tape would have been a possibility if the land were a bit more level. I have to admit, I wouldn’t mind actually running some tests with drip tape to see how drastic the pressure differences would be. Drip tape is VERY cheap by comparison to other options. But it is lightweight and rodents love chewing into it to get to the water in our arid climate.
I landed on pressure compensating drip tubing. I saw some in the big box stores but they did not have emitters close enough that I felt comfortable with. I ended up going with an online distributer for irrigation equipment that sold 12” emitter spacing lines. For each bed, I went with 2 lines. That means with a potential total of 48 beds on the half acre and a cost of $28 per 100’ line, that was a potential cost of over $2,500 not including any fittings. And fittings aren’t cheap either. I didn’t include them in my original price calculations. I should have planned on an additional $500 at least for fittings.
I knew going into setting up the irrigation that automating the process was an absolute requirement. I was still working part time and would not be at the farm every day to go turn on the drip lines. Based on the water pressure, I had calculated that I could run about 8 beds at a time based on the emitter rate, number of emitters per line, and lines per row. That would mean I needed enough timers to have 6 attachments to fit my total 48 beds. I found one timer that had 4 nozzles on it and was very configurable on time. I could select up to 4 time options per attachment and there were options for pausing during the irrigation to allow soakage. Bought it. Set it up. I thought I was set. Wrong.
The first thing I noticed when I turned it on was spotty drippage. Some emitters were producing fine. Others were lacking. Yet even others were totally dry. I emailed the drip line company asking if they had any suggestions. They thought my mainline running around the perimeter was too small given the amount of water coming out. So in my next set of beds, I up’d the mainline from 1/2″ to 3/4″. Same problem. I wanted to rule out the mainline all together so I hooked one drip line straight up to the faucet. No timer, no pressure regulator, no nothing. Worked perfect.
Hmm, well, since the increase in mainline size did not affect the output, the problem was between the mainline and the actual faucet, which was either the timer or the pressure compensator. I took the compensator off. No change. I unhooked the hose and just turned on the water so that it would run through the timer. Bingo. Significant water pressure reduction. Despite advertising as minimal impact to water pressure, this timer was cutting it down by 2 or 4 times. Big problem.
I thought it might be the brand of timer, so I bought two other brands. Still had the same problem. I have come to the conclusion that standard garden timers are simply not appropriate for the mid-sized farm. I know some smaller scale urban farmers using them with success on smaller plots, but they just aren’t robust enough for a mid-sized farm.
I did not have time to completely redo the irrigation, so I jerry-rigged two hoses to flow into the same output pipe, essentially doubling the pressure for each of my areas. This seemed to work well but still didn’t have enough pressure for total consistency.
I still have not solved this problem. I have abandoned buying any new timers. I’ve spent enough on those already. My next option is using manifolds driven by solenoids and a programmable timer, which is what you would see running lawn sprinklers. High throughput and minimal impact to water pressure. I will post in the future how that works, although I suspect it will be much better.
By this point in the year (about June), I had killed plenty of crop or had ridiculously uneven ripening in the ones that were ripe. In a last ditch effort to get some amount of crop, I bought some microsprinklers and just did mini-overhead watering for a few rows. At least that way I could do something. These actually worked well for germination. Unfortunately, the increased water on the pathways set loose weeds unlike I’ve ever seen before. Weed growth seemed to vary directly with my anger levels and indirectly with my overall success. My life seemed to be turning into a 9th grade algebra problem. The answer is “No Solution.”
Pressure Reducers, Filters, and Other Things You Don’t Think About
Pressure reducers are nice little contraptions that help reduce the pressure if you are using drip lines. The pressure compensating lines that I had already did that, but I still needed them because the drip lines themselves were not rated for as high of pressure as was coming out of the ouput.
Filters keep junk out of your irrigation lines. Many of the pressure compensating lines have contraptions in them that flush the lines before and after running since these lines often get used under the ground. But, filters are still a good idea if you don’t trust your water source. Algae may build up in your hose lines or there may be deposits that come lose. Over time, those can potentially clog your lines. (And don’t forget to clean the filters.)
One other fun feature from a timer I used is that when the batteries ran out, it relaxed the valve like a worn out sphincter and just let water gush right through it. (For the three people that aren’t my mom that read this, I hope you enjoy the peppered in use of the word “sphincter.” To my mother, I’m sorry.) This timer also had the great feature of no indication of battery level. Nothing like coming out to the farm to find a few rows absolutely saturated.
Back to Overhead and Next Steps
Despite my attempts to avoid overhead irrigation, I have come to the conclusion that it is cost prohibitive and just not effective on this scale. The picture below comes from Curtis Stone that shows complete row soakage using drip lines but that requires 4 lines per bed. That is just a little too much for me to spend right now. Plus I have no idea how he navigates those things using the precision seeder.
I have only prepped a 1/4 acre of the total 1/2 acre that I had planned to farm this year. I have decided to setup a giant shade cloth structure over this second 1/4 acre and use overhead sprinklers for watering. I will be using this area for the direct seeded crops and salad greens. Shade cloth will be up during the warmer times and off during the cooler times. Weed barrier is going down in between each row to hopefully keep the weeds under control and prevent it from turning into a jungle. I will have a future post about how well this is working. I am still in the process of setting it up.
- Experiment on the small scale. Irrigation costs add up VERY quickly. Even if it seems inconvenient, prove out your techniques in a small environment before making big purchases. You will save yourself heartache and extra costs later.
- Pick terrain-appropriate irrigation. Be aware of how elevations effect pressure within emitters or drip tape
- Give your direct seeded crops a little extra care when using drip lines. You need even water coverage for good germination
- Use screw-lock fittings if you want to go with higher pressure. Barbed and compression fittings work well if you have low pressure.
- Don’t underestimate the cost of all the elbows, T’s, valves, couplers, and other fittings. They add up when you have a lot of beds.
- Do not use standard hose timers for mid-sized irrigation areas. They are only appropriate for smaller plots of land.
Until next time,
The Failing Farmer