Best Drip Irrigation Kit for Gardens: How to Choose

Which Drip Kit Suits a Small Garden?

For two or three raised beds fed from a hose spigot, the kit to look for is built on 1/2-inch polyethylene tubing with inline emitters, and it comes with a backflow preventer, a filter and a pressure regulator. Colorado State University Extension describes drip irrigation as well suited to raised beds and block-style layouts, and it notes that inline emitters come every 6, 12 or 24 inches, with 12 inches the most common. Widely spaced plants and containers do better with point emitters on 1/4-inch tubing. Long straight rows suit drip tape, and a soaker hose only makes sense for a short, densely planted strip.

The reason to bother is water and plant health. Penn State Extension reports that drip may need less than half the water of sprinkler irrigation, and that disease pressure may be lower because the foliage stays dry. Utah State University Extension gives a similar figure, a reduction in water use of up to about 50 percent.

Check Pressure and Layout Before You Shop

Pressure decides whether a kit works at all. Colorado State University Extension puts typical household water pressure at 50 to 60 psi, while drip systems are designed to operate at around 20 to 30 psi, depending on the manufacturer. Drip tape runs lower still. Penn State gives its operating range as 6 to 15 psi and warns that tape may deform or burst at pressures as low as 30 psi. A kit sold without a regulator is a kit that needs one added.

Layout decides how much tubing to buy. Sketch the beds, then measure the distance from the spigot to the first bed, the runs inside each bed and the gaps between them. Colorado State’s design limits give the ceiling for a single zone: keep the mainline to 200 feet, and use 1/2-inch mainline where the total flow will stay under 200 gallons per hour. A small garden sits far inside both limits. Twenty-four emitters at 1/2 gallon per hour, for example, draw 12 gallons per hour. Gardens that come close to those limits are sized zone by zone in the guide to drip irrigation for a vegetable garden.

Slope matters on a hillside. The same source says to add 5 psi to the operating pressure for every 10-foot rise above the point where the system connects to the water supply.

Compare the Kit Types

The five common kit types differ in where the water lands and how much pressure they tolerate.

Kit type	Suits	Emitter spacing or flow	Limit to know
1/2-inch inline emitter tubing	Raised beds, block plantings, borders	Emitters every 9 to 48 inches; 12 inches is the most common	Spacing is fixed when you buy
1/4-inch inline tubing	Containers, narrow beds	Emitters every 6, 12 or 24 inches	Fewer spacing choices than 1/2-inch tubing
Point emitters on 1/4-inch lines	Shrubs, young trees, single large plants	1/2, 1, 2 or 4 gallons per hour each	More fittings to assemble
Drip tape	Long straight vegetable rows	Emitters every 8 to 16 inches	Runs at 6 to 15 psi and may burst at 30 psi
Soaker hose	A short, dense row or strip	Seeps along its whole length	Keep lines to 25 feet or less

Inline tubing is the least fiddly choice for vegetables in beds. Soil type sets the spacing to buy. Colorado State advises emitters 12 inches apart in sand, 18 inches apart in loam and 24 inches apart in clay.

Point emitters place water at one plant. The University of Georgia’s irrigation bulletin puts their flow at 1/2 to 2 gallons per hour, with 1 gallon per hour the most common, and says most are designed to work at 15 to 20 psi. Colorado State suggests two 1/2 gallon per hour emitters at the base of a perennial flower in clay or loam, and two 1 gallon per hour emitters set 12 inches from the base of a small shrub.

Drip tape is thin. Penn State lists wall thicknesses from 4 to 25 mil, where 1 mil is one thousandth of an inch, and suggests a 10 mil tape for a first-time user who wants a single-season product. A thin single-season tape suits an annual vegetable row better than a permanent bed.

Soaker hose lets water seep out along its entire length. To keep delivery uniform, Colorado State recommends short lines, generally 25 feet or less.

The Parts Every Kit Needs at the Spigot

The assembly at the faucet does more for reliability than the tubing does. For permanent systems, Colorado State gives the order of equipment as backflow prevention device, control valve, filter, then pressure regulator. On a hose-fed kit the control valve is the faucet handle or a mechanical or battery timer attached to it.

A backflow preventer keeps irrigation water from being drawn back into the household supply, and Colorado State calls it critical. Small antisiphon devices that screw onto a hose bib are made for add-on systems like these.

The filter protects the emitters. Drip needs relatively clean water, and a 150 to 200 mesh filter is the range Colorado State gives for municipal supplies. Penn State lists the same 150 to 200 mesh as required for most drip tapes. Georgia’s bulletin advises cleaning filters and screens periodically.

The regulator comes last, so that it holds a steady low pressure in the lines beyond it. Colorado State warns that high pressure may split the hose and pop connections. The same source says the low pressure is easy to achieve with regulators that have hose-end fittings. After the regulator comes the adapter to 1/2-inch tubing, and the mainline can run up to 200 feet in one zone.

Check the box for the small parts as well: end closures so that each line can be opened and flushed, and stakes. Colorado State recommends wire anchors every 3 feet to keep lines in place.

Work Out the Run Time

Run time follows from emitter count and flow. Take a 4 by 8 foot bed with three 8-foot lines of inline tubing, emitters every 12 inches, each rated at 1/2 gallon per hour. That is 24 emitters and 12 gallons per hour.

One inch of water over one square foot is 144 cubic inches, or about 0.62 gallons, so an inch over the 32 square feet of that bed comes to roughly 20 gallons. The system in the example delivers that in about 100 minutes. Utah State University Extension reports that most commonly grown vegetables in Utah need 1 to 2 inches of water per week, and that in a loamy soil 1 inch of water penetrates around 6 inches deep. Other climates will differ, so treat the figure as a starting point.

Then let the soil correct the arithmetic. Colorado State’s advice for vegetable beds is to irrigate when the top 2 to 4 inches of soil is dry to the touch and to set the run time by examining soil moisture after a cycle. For ornamental plantings, the same extension service says systems are generally designed to run for one hour per week once plants are established.

Run times change with the weather, and a summer watering schedule shows how to adjust them through the hot months. Pots on a drip line also depend on a mix that drains well, which the guide to potting mix for containers covers.

Flush, Check and Winterize

A drip kit needs little upkeep, and what it needs is cheap. Before irrigating for the first time in spring, flush the mainline to clear accumulated dirt. Georgia’s bulletin adds a yearly task: open the end of each lateral line once a year and flush out the sediment.

During the season, walk the lines while the system runs. If an emitter stops dripping, Colorado State’s fix is to soak it in water and clear the particles with forced air, and Georgia’s reminder to clean the filter screen applies here too.

Before freezing weather, uncap the mainline and let it drain. Colorado State notes that systems with many right-angle fittings may hold water and need pressurized air to blow it out, which is a reason to keep a small layout simple.