Raised bed watering system

If I could choose the best investment for a raised bed garden (or a vegetable garden, generally speaking), that would be an automated irrigation system. Sprinklers and hand watering can get the job done, but they are just inefficient systems. Even for small gardens, hand watering every day is time-consuming and just not a good use of one’s time. We have 14 raised bed gardens, six in-ground beds, and our food forest area, and when hand watering everything, we would spend 2-3 hours every day. I finally decided that we needed to invest in an automated system and learn how to install one. I was confused and overwhelmed at first with all the options and parts, but after watching a lot of videos and talking to two companies that sell drip systems, I was able to understand (still not an expert, but it doesn’t intimidate me anymore) and install ours.

Why drip irrigation system?

While many irrigation systems are available, some are more efficient than others. When picking drip, I looked into water efficiency, price, durability, safety, and ease of installation. Drip irrigation knocked out of the park in all those aspects, so it was an easy decision, but let me give you some data to back up this information. When it comes to water efficiency, drip is the most reliable system using over 90% of the water applied, while sprinklers only use 65-75%. This system delivers water directly into plants’ root ball. While there are different thicknesses to the drip tape and factors such as sunlight will affect its durability, this system can last up to 10 years! While figuring out the system was a little complicated for me, installing it was quite simple; it was almost like a lego!

Many pathogens in plants are carried through the water, so when water hits plant leaves directly through irrigation, it makes plants susceptible to any pathogen that may be in the water. The members of the cucurbit family (cucumber, melons, zucchini, and others) are highly susceptible to waterborne fungi called powdery mildew. In order to avoid or reduce those pathogens watering close to the root ball is highly recommended.

How does drip irrigation work?

Just like the name suggests, this system works by “dripping” the water. The drip tubbing/tape has emitters set in a determined spacing that could be every 4-24 inches apart. Those emitters will drip a set quantity of water that will vary from 0.25 gallons per hour to up to 1 gallon per hour. Since this system works by slowly dripping water from its emitters, the water pressure required to run is much lower than other systems, running 8-15 psi.

Choosing your system

There are many ways you can design your raised bed irrigation system, and there are also good alternatives. A second option that was in my thoughts was using a soaker hose. However, Florida water is considered “very hard.” This means that the water has a high amount of minerals per litter (180 mmg), so a soaker hose wouldn’t be durable for us as it has the potential to get clogged up. Another downside for us was the financial investment in the soaker hose compared to the drip system. Each food-grade soaker hose would cost us approximately $100 for each raised bed, and this is not counting all the other parts we would have to order.

Setting up a drip irrigation system.

I am not an expert on irrigation, so the instructions that I will be providing on this part are based on what I have learned and how I designed my garden irrigation system. Use this blog post as a guide and make any changes to your system as you see fit.

Before picking the size for the main line tubbing, you will need to calculate the flow rate (total gallon per hour) output of your system. It sounds complicated, but its actually quite simple; here is a video explaining how to do it https://www.youtube.com/watch?v=xrCAc2mz3yo . Based in the flow rate of our house, the 3/4 inches of poly tubbing was the right size to set up our system.

Y splitter

This is not necessary, but I highly recommend buying one. This will allow your faucet to have an available “side” in case you need to use water for other reasons.

Backflow preventer

Although not shown in the picture, we have a backflow preventer in our faucet. This works by preventing water from the irrigation system from flowing back into your water.  https://www.dripdepot.com/product/hendrickson-bros-j10-hose-vacuum-breaker Hendrickson Bros J10 Hose Vacuum Breaker

Timer

Although we manually set up our time any time the irrigation system is on, this system also allows us to set up irrigation automatically. We prefer to manually turn it on because we irrigate the backyard based on how many rain events we get and different times of the year rain more than others. Even though it is not a necessity, I highly recommend adding one as it is very easy to forget the irrigation system as it is pretty silent. You can get one by clicking here:

Filter

As I have said earlier, water is filled with minerals which depending upon your area, can make the water “very hard.” Those minerals build up in the irrigation system clogging up the drip line, so adding a filter is a must to ensure your irrigation system works. Here is a link to the filter: https://www.dripdepot.com/product/three-quarter-inch-hose-thread-filter 3/4″ Hose Thread Filter.

PSI regulator

As I have mentioned earlier, drip works by slowly dripping water through the emitters at a set rate. The water pressure from your house is too high for the drip tape, so the regulator comes in to reduce the water pressure in order to match the pressure of your drip tape. I have seen people using the PSI regulator in a couple of different ways. One is setting up a PSI of 25 in the faucet and adding 15 PSI regulators or less close to your beds or one on each raised bed. Normally this first option is chosen when the faucet is further away from the beds to ensure that the pressure doesn’t fall too much by the time it reaches the raised beds. Since our raised beds are extremely close to the faucet, we chose just to install a 15 PSI regulator on the faucet. You can get the PSI regulator here https://www.dripdepot.com/product/senninger-three-quarter-inch-hose-thread-pressure-regulator Senninger 3/4″ Hose Thread Pressure Regulator – PSI : 15 PSI

Adapter

The adapter serves to convert the male hose thread fitting into the poly tubing fitting. Our poly tubing is 3/4 an inch wide.  https://www.dripdepot.com/item/irritec-perma-loc-tubing-by-female-hose-thread-swivel-fhts-adapter-thread-size-three-quarter-inch-fht-perma-loc-size-three-quarter-inch

Poly tubbing

This is the main line that will run to your raised beds. Based on our water flow, the 3/4 inch is the right size. To determine how much you will need is necessary to measure the distance of your faucet to your beds and any connections you will need to make. I recommend ordering a little more than you think you need in case of mistakes and if any line breaks. Polyethylene Tubing – Size : 3/4″ (.820″ ID x .940″ OD) – Length : 500′ https://www.dripdepot.com/product/polyethylene-tubing   

Spacing and installing the system on your bed

How far apart you will need each line will depend upon how far apart your emitters are, what kind of soil you have, and other factors. For our beds, I spaced each line around 10 inches apart (most of our beds are 6×3 feet). I recommend keeping your lines no more than 12 inches apart. Our emitters are spaced 6 inches apart, dripping 0.25 gph.

Drip tape

This is the line that will drip the water into your beds. There are different thicknesses, spacing, flow rates, and sizes. We chose 15 mil thickness tape as it is made to last longer. Our emitters are 6 inches apart and flow at a 0.25 gallon per hour rate. The size will depend on how many beds you have. We purchased enough to cover all of our raised beds, plus inground beds and the side yard perennial area. You will need to measure how many lines you can run on each bed and how many beds you have. https://www.dripdepot.com/product/p1-ultra-five-eigths-inch-drip-tape P1 Ultra 5/8″ Drip Tape – Wall Thickness : 15 mil – Emitter Spacing : 6″ – Emitter Flow : 0.25 GPH – Roll Length : 1000′

Tape x barb adapter

The adapter will connect the main line to the tape. You will need a hole puncher tool to make the holes into the poly rubbing. https://www.dripdepot.com/product/irritec-perma-loc-tape-by-barb-tubing-takeoff-adapter Irritec Perma-Loc Tape x Barb Tubing Takeoff Adapter – Barb Size : 3.6mm – Perma-Loc Size : 5/8″

Tubbing elbow

This part is a connector of two tubbing parts, and it serves to turn the line into a 90-degree angle. Elbow link https://www.dripdepot.com/product/irritec-perma-loc-tubing-elbow 3/4 inch permaloc elbow. 

End clamp

The end clamp serves to stop the water from flowing at the end of the header. https://www.dripdepot.com/product/irritec-figure-8-tubing-end-clamp Irritec Figure 8 Tubing End Clamp – Size : 3/4″

Valve

The shut-off valve is not a necessity for every raised bed, but I highly recommend adding one. This will allow you to turn off the irrigation in each bed if needed for any reason. For example, I had one of the lines blow up (due to user error, I didn’t attach the tape x barb adapter properly), and to fix it, I simply turned the irrigation off on that bed and reattached the barb adapter. https://www.dripdepot.com/product/irritec-perma-loc-tubing-coupling-valve Irritec Perma-Loc Tubing Coupling Valve – Size : 3/4″

Line tubbing

This is the main line that the water will flow through to make your raised beds. https://www.dripdepot.com/product/irritec-five-eigths-inch-drip-tape-end-closure  

How long should I run my drip system?

The amount of time that you should run your system will depend on a couple of factors:

  • When was the last rain event?
  • What kind of soil do you have?
  • How many drip tapes do I have on each bed? How much water can it provide to my beds?

Now that you have those questions in mind, I recommend heading over to the University website and reading the chart they created to determine how long you should water your beds. I personally water anywhere from 40-60 minutes when I feel the need. I like to feel the soil before deciding if I should turn on the irrigation. This method of feeling the soil moisture can be confusing for many an alternative is buying a moisture measuring device. The soil moisture should be around 40-80%. For newly transplanted seedlings, I recommend daily watering for at least two weeks unless there are daily rain events. https://extension.psu.edu/determining-how-long-to-run-drip-irrigation-systems-for-vegetables

Final thoughts

 An irrigation system is not a necessity for vegetable gardening or raised bed gardening. However, not being a necessity doesn’t make it less valuable. Depending on the size of your garden and how you want to utilize your raised beds I highly recommend installing one. It is never fun to lose hours of your day under the hot sun or a cold breeze watering your raised beds.

PSA: you will be redirected to the drip works website by clicking on the links I will be adding throughout this blog post. I highly recommend checking the sizings and fittings before checking out. You will notice that there are many options and fittings that look very similar, but there are not the same. It is also important that you check your water outcome before ordering the poly rubbing and other parts. For example, if you use the 1/2 inch poly tubbing your elbow, “Ts”, valve, and other parts will need need to be at the same size. The links I provided here for those parts won’t be the right ones for you, 1/2-inch poly tubbing needs a 1/2-inch valve, 1/2-inch T, and so on.

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