A drip irrigation system provides a slow stream of water to your plants, allowing the moisture to seep into the soil steadily but slowly enough so the soil can thoroughly absorb the moisture. A DIY system costs less than a drip irrigation kit and can be constructed to fit your specific growing needs. Building a gravity-fed system requires no special tools and is a suitable project for the novice. The system does require periodic refilling and must be turned on manually.
A gravity-fed system works well for a DIY project because it requires no pumps. Pumps can be expensive, loud to operate and difficult to install. A reservoir holding the water sits above the top of the planter pots, and gravity bring the water down to the soil. A manual shut-off valve is necessary to prevent the system from running constantly, and the reservoir does require periodic refilling. Any large container works well as a reservoir, although 5-gallon lidded buckets are the simplest to acquire and modify. Gravity-fed systems have enough water pressure to irrigate approximately five plant pots.
Emitters and Hoses
The hose used for a drip system is called a micro-inline irrigation hose. This hose has a diameter of 1/4 inch and is typically made of flexible vinyl. The hose is inserted into a hole drilled near the bottom of the reservoir. An irrigation emitter delivers the water to the planter, with an emitter placed along the hose at each pot. Inline emitters allow you to connect a hose to each side, while terminal emitters allow only one hose attachment and are used at the last planter on the irrigation system.
A micro-inline shut-off valve controls the water flow through the irrigation system. The valve is placed at the beginning of the hose shortly after it emerges from the reservoir. The valve must be turned to the off and on position manually. Automatic valves are also available, but you still must keep the reservoir filled manually. While clear or translucent buckets can encourage algae growth, they are suitable for indoor use if you water with tap water and keep the bucket out of direct sunlight.
Clogged emitters can cause the system to fail. Emitters need periodic cleaning to remove mineral deposits. A vinegar bath and thorough scrubbing usually returns them to working order, but occasionally an emitter may require replacement. Water pressure concerns are usually solved by either filling the reservoir or placing it in a location higher than the planters. Leaks rarely occur along the friction-fitting emitters and hoses, but if they do, plumber's tape can seal the leaking area.