Permanent Raised Bed Gardening: Installing a Drip Irrigation System

A fertilizer injector makes "fertigation" (the application of fertilizer through the drip system) possible.

Components
When selecting system components, make sure they are adequate or even necessary. Many name brand manufacturers furnish a do-it-yourself guide to assist with component selection.

Anti-siphon valves are mandatory in most municipalities. Check local ordinances to determine the type of device required.

When selecting a pressure regulator, make sure it is matched with the system operating pressure. Excess pressure can cause rupturing of the emitter lines. Inadequate pressure will result in a lowered flow rate, increasing the time required to water.

Drip systems using city water do not require a filter. However, contamination can occur as the result of water line breaks. Therefore, protect your system by installing a filter having a minimum 150-mesh screen size. If you plan to obtain water from a river, pond or lake, the drip system will require a more sophisticated, and expensive, filter. Consult an irrigation specialist or product representative for details.

A water timer may sound like a good idea, but, if depended on exclusively, can lead to a false sense of security, not to mention poor crop performance. Plants require water based on need, not on any particular schedule. A plant's need changes based on maturity and weather conditions. Therefore, use a timer only as a last resort.

A fertilizer injector is required if you plan on fertilizing. As mentioned earlier, this is the preferred method of fertilizing crops grown under plastic mulch. Before you purchase an injector, make sure it can operate at the low pressure and flow rates common to small garden drip systems. See the section 'Selection and Use of Fertilizer Injectors' for details.