Installing a Drip Irrigation System for Raised-Bed Gardening
Drip irrigation systems use plastic tubing with small emitters, or holes placed at regular intervals. These emitters drip water at a chosen, usually slow rate. It’s the perfect irrigation system for water conservation. Using a drip irrigation system increases your options for watering. It protects the land and provides numerous benefits to your plants. Plus, these systems are easy to install, move as plants grow or in a garden bed new plants are added or taken away.
These effective watering systems have three basic parts:
- Valve, regulator and filter with a controller
- Plastic hose or pipe (thick-walled hard hose is best)
- Emitters (usually at twelve or eighteen-inch intervals)
Remember, measure twice, cut once.. Design your system using a scale drawing of your bed. Locate your water source; ideally, it should be within 100 feet of your bed. This is not likely to be a problem in most backyards.
You’ll need to figure out how much line to buy. Just multiply the number of lines per bed by the length of the bed. You will want two lines for a forty-inch bed. If your bed is more than four feet wide, you will need three lines. Beds two feet or less in width only need one line.
Next, you will need to figure out your system’s flow rate. Don’t worry it’s not that difficult. The manufacturers label flow rate as either gallons per minute (gpm) per 100 feet of line or gallons per hour (gph) per emitter. Most home faucets provide 5 g.p.m. If your system has 400 emitters, rated at one g.p.h. each, your faucet needs to supply 400 g.p.h. Divide by sixty to find the g.p.m. In this case, it’s 6.6. Your home faucet doesn’t provide enough. You can either add a new faucet or water half the garden at a time.
The friendly staff at Hydro-Scape is glad to help you figure this out, too. They’ll also help you determine the size of main line you need (the line that runs between the faucet and the line and emitters. A general idea for supply lines less than 100 feet long is:
- 1/2” line for flow rates up to 2 g.p.m.
- 3/4” line for flow rates up to 4 g.p.m.
- 1” line for flow rates up to 8 g.p.m.
Certain municipalities have valve requirements. You may need a filtration system depending on your water source. We’re happy to help you with these issues! Just ask one of the Hydro-Scape staff.
Installing Emitter Lines
There are some basic things to remember when installing your emitter lines:
- In forty-inch beds with one, two or three planted rows, place the lines twelve inches apart. Start at the centerline of the bed and put one line on either side of the centerline, six inches from it.
- Keep the lines straight. It’s the only way to know where they are when buried and will keep you from damaging them when planting.
- Simply press the lines into the soil by hand, approximately one inch deep. The soil should be loose and easy to crumble. After burying them, press down the soil and hold in place with staples.
- If you’re keeping them on the surface, mound soil over them at certain points or use landscape staples to keep them straight.
- Keeping the lines on the surface gives you the benefit of using the lines as planting guides. So you get straight rows of plants to space your transplanted seedlings. Pack the soil down before placing the lines.
- Flush the emitter lines before capping them off to get rid of loose soil or other debris from installation. You should flush the main and header lines before attaching the emitters.
Enjoy gardening and saving water when you’re using a drip system. It waters only what is needed, with no waste.