Installing sprinklers: how to get under the sidewalk
Publication Date: Friday Oct 18, 1996

Installing sprinklers: how to get under the sidewalk

Best way is to use your garden hose

by Scott Loosley

A I am installing new sprinklers in my yard and would like to irrigate the parking strip area along the street. Do you know of an easy way to get the pipe under the sidewalk? I was thinking of digging under the walk, but wasn't quite sure how to approach the task without making a massive hole. Do you have any ideas? A There are a couple of different ways to approach this job. The easiest way to get a single piece of pipe under a sidewalk is to use hydraulics. This involves the simple task of attaching a jet nozzle to one end of a piece of PVC pipe and a garden hose to the other. The force of the water creates a hole that the pipe is pushed through. Here is how you do it. Start by going to your local irrigation supply store. Your parts list should include a brass jet nozzle, the kind you can attach to the end of a hose, a length of schedule 40 PVC pipe long enough to reach the entire distance under your sidewalk, a PVC male hose end adapter fitting, a PVC female hose end adapter fitting, and a can of wet-dry PVC glue.

Dig your trenches on either side of the walk to the depth of the rest of your sprinkler system, usually about 12 inches minimum. Using a hacksaw or PVC pipe cutter, cut the piece of schedule 40 PVC pipe about two feet longer than the width of your sidewalk. Following the directions on the can of PVC glue, attach both the male hose end adapter and female hose end adapter to the opposite ends of the pipe. Let the fittings dry for a few minutes, as recommended on the glue label.

Once the fittings are dry, attach the jet nozzle and hose to the piece of pipe. Place the pipe in the bottom of the trench and turn on the water. As the force of the water creates a hole in the soil, firmly push the pipe under the walk. This may require thrusting the pipe in and out several times until you reach the opposite side of the walk.

Once your pipe is through, shut off the water and cut the hose end fittings from both ends of the pipe. You can now glue the rest of your sprinkler system together.

Some situations will require tunneling by hand, especially if there isn't room to maneuver a long section of pipe. If your soil is just too tough to dig by hand or hydraulically push a piece of pipe through, there are machines that will bore a hole under your sidewalk. Contact an irrigation or landscape contractor for information about mechanical boring devices.

Q We recently had a very large Deodar Cedar removed from our front yard and the stump ground out. The location is next to our front lawn. We were thinking about planting a redwood in this location, but would accept any suggestions you might have. A Before you decide, think about some of the influences the new tree might have on your yard. Do you want a deciduous or evergreen tree? How fast does the tree grow and what is the mature size? How will the roots affect the area around the tree? Do you want a flowering tree or one with fall color? How much water will it need? Careful planning before you plant will make maintenance easier in the years to come. If you are intending to keep a lawn in this area, I would not recommend a redwood tree. The roots of redwoods are very invasive and will end up competing with the lawn, eventually winning.

When choosing a tree, I like to think of how it can help my property. What is the location of the tree in relation to my house? If the site is on the south or west side of the house, a deciduous tree may be a better choice. This way the leaves can shade the house in the summer and let sunlight through in the winter.

If your yard is large, you might consider a Scarlet Oak (Quercus coccinea) or Ginko (Ginko biloba). If a medium-sized tree is desired, a Tupelo (Nyssa sylvatica), Chinese Tallow Tree (Sapium sebiferum) or Raywood Ash (Fraxinus velutina) would be a good selection. All of these trees are deciduous and have striking fall colors. Now is the time to select a deciduous from a nursery. If a specific fall color is desired, you can see what you'll get as they go dormant this season.

You may really want an evergreen, though. There are a wide variety of trees to choose from. A couple of my favorite oaks are the Holly Oak (Quercus ilex) or the Cork Oak (Quercus suber). For an interesting specimen tree, try Arbutus `Marina.' This tree resembles the Strawberry Tree (Arbutus unedo), but has larger leaves and pink urn-shaped flowers in the fall. If a striking display of winter blossoms is desired, try Michelia doltsopa. This magnolia relative has a beautiful habit and a profuse display of creamy white, fragrant blossoms in January.

Now that you're more confused than before, take some time to walk through your neighborhood or visit a local botanical garden or arboretum to get ideas. It is also a good idea to see what is available at your local nursery. If they don't have what you're looking for, ask if they can special order for you. Take some time to make the right choice.

Scott Loosley is the horticulturist at the Gamble Garden Center in Palo Alto. Send questions to Loosley care of Palo Alto Weekly, P.O. Box 1610, Palo Alto, CA 94302.

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