If you garden in raised beds, there is no improvement that will save you time and enhance results better than drip irrigation. The time spent installing a drip irrigation system will be returned many times over in the first season alone, not to mention over the many years of use you should get out of a well-planned system made from durable materials. Plants grown using drip irrigation grow better because they receive more uniform watering. It is easier to water with ironclad reliability when the task is reduced to simply turning your faucet on and off, or assigned to an automatic water timer.
There are many drip irrigation tubing products on the market today, but none match the ease of use, durability, reliability and fine engineering of in-line emitter tubing. Our philosophy: do the job well the first time using top quality materials, and you won’t need to do it again anytime soon.
In-line emitter tubing comes with pre-installed emitters every 6”. You simply roll the tubing off the coil, cut to size with heavy-duty scissors and install it in your beds. The 6” spacing between emitters provides a continuous band of water on either side of the tubing. You can plant small seedlings adjacent to the emitters on either side of the tubing. You can also sow seeds.
Photo, above: A three-line irrigation layout.
The standard dimensions of most raised beds are 4’ x 8’. While the length of your beds is not critical when you determine the layout of your system, it is important to have the right number of lines running across the width of your bed. Too few lines and you will have gaps in water coverage. Too many lines and you will waste water, promote weeds and clutter the surface of the beds with unnecessary tubing.
The ideal number of lines in a 4’ wide raised bed is three, with one running down the middle of the bed and one either side, 16” from the center line (see photograph above).
If your beds are 3’ wide, two lines 18” apart centered over the middle will be do the job well.
Photo, right: Easy-to-insert fittings.
Installation of your tubing is easy and straightforward. You simply cut each line leaving the overall length of each line about 12” short of the total length of your beds. For example, if your beds are 8’ long, 7’ lengths of tubing inset 6” from either end will be adequate.
The drip lines running the length of your beds connect at one end using solid feeder line and plastic connectors that insert into the tubing. Once inside, the connectors don’t come out. Stay away from systems that require clamps and glue as these are unnecessarily complicated and no more effective.
Use solid feeder line to come up the side of your wooden frames from ground level (see image at right). If you wish, a manual shut-off valve can be installed here so you can turn the water off any bedsthat aren’t in active use.
In addition to connecting your raised beds, solid feeder line also leads back to your faucet. A Y connector on your faucet will allow you to make a permanent connection to your raised beds and leaves the other side of the Y for a garden hose. It is highly recommended that you attach a series of components to your faucet to filter your irrigation water and control the pressure. We have such an assembly, ready-to-use, called a Low Volume Control Kit.
You should run your drip irrigation system daily for optimum plant growth. Vegetable plants grow their best with a steady supply of water. Lengthy intervals without water will put stress on your plants. This results in diminished growth and lower yields.
Photo, right: A low-volume control kit.
How long you water each day depends on a range of factors: the size and maturity of your plants, air temperature, wind, cloud coverage, and the intensity of the sun. In general, you need less water early in the season and more water late in the season when the plants are larger, transpire more and are producing fruit.
You’ll need to consider these variables along with the amount of water your tubing dispenses over a unit of time, i.e., how many gallons per minute (GPH) per emitter. Our raised bed system uses emitters that dispense water at the rate of .4 GPH. That’s slightly less than ½ gallon per hour. Assuming your plants need about a pint of water per day early in the season, using the same tubing you would run a daily watering cycle that is 15 minutes long. By the end of the season the watering cycle might be 45 minutes long in the morning, with a shorter, 15 minute cycle at the end of long, hot days to replenish water loss.
It’s worthwhile to read about drip irrigation, but better yet to take the first step to install your system. We all suffer from inertia, but I can assure you, the time spent installing drip irrigation in your garden is time well spent.
Don’t bite off more than you can chew. If you have a large garden, select a section where drip irrigation will give you the biggest bang for your buck, and then begin. Once you’ve tackled a small project you’ll have the confidence and desire to irrigate all parts of your garden using drip irrigation. The benefits are just too practical to ignore.
We’ve got a new TomatoCam video from our trial garden you might enjoy. It shows how we prune tomatoes.
See you in two weeks, when we will take a look at How We Propagate and Grow Lavender.
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