Drip irrigation for a kitchen garden: beds, rows and run times.
Leafy vegetables, tomatoes and peppers need steady water through the dry season, and drip puts it on the soil, where the roots are. This guide helps you decide how to lay dripline on your beds, whether a tank can feed it or a pump is needed, and how long to run the zone as the crops grow, with a worked example.
Written for homeowners and estate and facility managers. Updated .
Key points
- Give the vegetable beds a zone of their own, apart from the lawn and the shrubs, because their need changes as the crops grow.
- Lay dripline rows along each bed, on the soil and under mulch, so the water reaches the roots and the leaves stay dry.
- Work out each day's water from the weather and the crop's stage, and raise the run time as the crops grow.
- Check the pressure your dripline needs: a tank on a stand rarely gives enough, so plan a pump, a filter and a regulator.
- Walk the beds while the zone runs, and flush the rows and clean the filter on a schedule.
On this page
Why vegetables need their own zone
A hydrozone is a group of plants with similar water needs and similar rooting depth, in similar sun and soil, watered together on one valve with its own run time. California's landscape water rules define it as a section of the landscape with plants of similar water needs and generally similar rooting depth.
A kitchen garden is a hydrozone of its own. Vegetables use little water as seedlings and much more as they flower and fruit, so their run time changes week by week. They also want water on the soil, not the leaves: the University of Florida's extension service notes that overhead watering can encourage disease, while drip puts water on the soil around the roots.
So give the beds their own valve, apart from the lawn's sprinklers and the shrubs' drip, as Hunter's drip guide does for every hydrozone.
Sources: California Code of Regulations, Title 23, section 490.2 (2025), Model Water Efficient Landscape Ordinance: definitions of hydrozone and plant factor; FAO (1998), Irrigation and Drainage Paper 56: Crop Evapotranspiration, chapter 6, Table 12; UF/IFAS Gardening Solutions, University of Florida (checked 2026), Watering the vegetable garden; Hunter Industries (2015), Drip Irrigation Design and Installation Guide (LIT-496), page 10.
Vegetables for a Nigerian kitchen garden
NIHORT, Nigeria's National Horticultural Research Institute, publishes growing guides for vegetables widely grown in Nigeria, among them these four.
| Vegetable | Grown for | What NIHORT says about water |
|---|---|---|
| Amaranth, tete or aleho (Amaranthus species) | Leaves, from about four weeks after sowing | Lack of water brings early flowering and fewer leaves to pick; water well after sowing or transplanting. |
| Jute mallow, ewedu or rama (Corchorus olitorius) | Leaves; grown all over Nigeria | Prefers sandy loam rich in organic matter and grows poorly on heavy clay; in the savanna and Sahel zone, NIHORT says, it grows most strongly in the hot rainy season. |
| Fluted pumpkin, ugu (Telfairia occidentalis) | Leaves and seeds, from a climbing vine, usually staked | Grows all year where water is available; irrigation is essential in the dry season; water plants from the base. |
| Tomato (Solanum lycopersicum) | Fruit; among the most grown fruit vegetables in Nigeria | Thrives with irrigation in the dry season, and NIHORT rates drip the most effective method. |
Irrigating tomatoes, peppers and onions
Sources: NIHORT, National Horticultural Research Institute, Ibadan (posted 2020), Amaranth production guide; NIHORT, National Horticultural Research Institute, Ibadan (posted 2020), Corchorus production guide; NIHORT, National Horticultural Research Institute, Ibadan (posted 2020), Fluted pumpkin (ugu) production guide; NIHORT, National Horticultural Research Institute, Ibadan (2023), Tomato production guide.
Crop factors for vegetables
The kitchen garden follows the series' two steps, with FAO's crop factors in place of a plant factor, as the crop guide does. The first is ETo, the weather's drying power, in mm a day. For a dry-season month in the north and centre the series uses 6 mm a day: a field study at Afaka, Kaduna State, found monthly averages of about 5.5 to 6.6 mm a day from December to March, and FAO gives 6 to 7 mm a day for a semi-arid climate at 15 to 25°C. The south and the rains run lower.
The crop factor is low while plants cover little ground, peaks once they cover it, and falls towards the end of the season. Water need in mm a day = ETo × crop factor. FAO's table has no amaranth, jute mallow or fluted pumpkin, so this guide uses its small-vegetable group for them.
| Crop or group, from FAO's table | First stage | Peak | End of season |
|---|---|---|---|
| Small vegetables, such as spinach, lettuce and cabbage | 0.7 | 1.05 | 0.95 |
| Tomato | 0.6 | 1.15 | 0.70 to 0.90 |
| Sweet pepper and egg plant | 0.6 | 1.05 | 0.90 |
| Cucumber, fresh market | 0.6 | 1.00 | 0.75 |
Crop factors by stage, in the crop guide
Sources: Onwuegbunam and others (2025), Actual crop coefficients and yield response factors of irrigated tomato in Afaka, Northwest Nigeria, Journal of Applied Life Sciences and Environment 58(1): study location and Tables 1a and 1b; FAO (1986), Irrigation Water Management Training Manual No. 3: Irrigation Water Needs, chapter 3, Tables 5, 6 and 14; FAO (1998), Irrigation and Drainage Paper 56: Crop Evapotranspiration, chapter 6, Table 12.
Dripline rows along raised beds
NIHORT raises amaranth in the dry season on beds about 90 cm wide and 20 cm high, higher in the rains. Run dripline along each bed: pipe with drippers built in. Pressure-compensating (PC) dripline gives the same flow over a range of pressures, so the far end of a bed gets as much as the near end.
Hunter's drip guide sets the spacing by soil, because water spreads further sideways in finer soils. Converted from inches: drippers about 30 cm apart with rows 30 to 45 cm apart on sand, 45 cm with rows 40 to 55 cm on loam, 60 cm with rows 45 to 60 cm on clay, and the tighter spacing when unsure. A 90 cm bed takes two rows, or three on sand.
Lay the rows on the soil under mulch. The University of California's master gardeners advise against burying them, so you can see them work and mend them; mulch shields them from the sun. A shut-off valve on each row lets you rest a bed. Cap the far ends so they can be opened, because Hunter's guide calls for flushing on every dripline zone. Thickly sown seed may need hand watering until it comes up.
- Tank on a stand: it stores the water, but on its own gives dripline too little pressure
- Pump: raises the pressure to what the dripline needs
- The kitchen garden's own valve: the lawn and the shrubs are on other valves
- Filter and pressure regulator: keep grit out of the drippers and the pressure in range
- Pipe along the ends of the beds, feeding each dripline row
- Leafy vegetables: two dripline rows on the soil, capped at the far end for flushing
- Staked tomatoes: the drippers wet the soil at the base, and the leaves stay dry
Drip tape or dripline?Hunter HDL-PC driplineHunter PLD dripline fittings
Sources: NIHORT, National Horticultural Research Institute, Ibadan (posted 2020), Amaranth production guide; Hunter Industries (2015), Drip Irrigation Design and Installation Guide (LIT-496), pages 8 and 11; Hunter Industries (2026), Product Catalogue Vol. 41, EMEA metric edition, page 172; UC Master Gardeners of Sonoma County, University of California Cooperative Extension (2016), Drip irrigation in the food garden, publication 011-002; FAO (2007), Handbook on Pressurized Irrigation Techniques, chapter 3, sections on drippers, drip tapes and pressure-compensated emitters.
Tank or pump: the pressure dripline needs
Flow is how much water passes in a set time, in litres per hour (L/h) for a dripper, or cubic metres per hour (m³/h) for a pump or a pipe; one cubic metre is 1,000 litres. Pressure is how hard the water pushes inside the pipe, measured in bar. Head is pressure given as a height of water, in metres: one bar is about 10 metres of head.
A tank feeds by gravity, with a pressure set by the height of its water above the beds. Hunter's PC dripline needs 1 to 4.2 bar, so at least about 10 metres of head; FAO puts drippers in general at about 1.0 bar, and even drip tape at 0.6 to 1.0 bar. A tank on a stand a few metres high gives only a few tenths of a bar, and less as it empties: not enough on its own.
So put a small pump between the tank and the zone, chosen for the zone's flow (the drippers' flows added together) and the pressure the dripline needs, plus what the pipes and filter lose. A borehole pump or a town supply with enough pressure can feed the zone directly, through the same filter and regulator.
Raised tanks and pressureChoosing a pump for your water source
Sources: FAO (2007), Handbook on Pressurized Irrigation Techniques, chapter 4: System design; FAO (2007), Handbook on Pressurized Irrigation Techniques, chapter 3, sections on drippers, drip tapes and pressure-compensated emitters; Hunter Industries (2026), Product Catalogue Vol. 41, EMEA metric edition, page 172.
Filter, valve and controller
Hunter's drip guide starts every drip zone with three items: a zone valve, a filter and pressure regulation, and says to filter whatever the supply, because even drinking water carries particles that can clog drippers. Its PC dripline needs water filtered to at least 120 mesh (125 microns).
For a home garden zone, Hunter's filter regulator does both jobs in one fitting: a 150 mesh screen, finer than the dripline needs, and an outlet pressure of 1.7 or 2.8 bar, inside the dripline's range. A regulator only lowers pressure, so the pump must give more than its setting. A bigger zone, or dirtier water, may need a separate filter.
If the water comes from a drinking-water supply, fit a backflow preventer where the garden line leaves it, as the University of California's master gardeners advise. A mains controller runs the zone on a programme of its own; with no power nearby, a battery controller on the valve can do the same. Either way, ask how the pump will start when the valve opens.
Hunter filter regulatorHunter HY filterHunter PGV zone valveHunter X-Core controllerChoosing a drip irrigation filter
Sources: Hunter Industries (2015), Drip Irrigation Design and Installation Guide (LIT-496), page 10; Hunter Industries (2026), Product Catalogue Vol. 41, EMEA metric edition, pages 133, 169 and 172; UC Master Gardeners of Sonoma County, University of California Cooperative Extension (2016), Drip irrigation in the food garden, publication 011-002.
Working out a run time
Sources: Onwuegbunam and others (2025), Actual crop coefficients and yield response factors of irrigated tomato in Afaka, Northwest Nigeria, Journal of Applied Life Sciences and Environment 58(1): study location and Tables 1a and 1b; FAO (1986), Irrigation Water Management Training Manual No. 3: Irrigation Water Needs, chapter 3, Tables 5, 6 and 14; FAO (1998), Irrigation and Drainage Paper 56: Crop Evapotranspiration, chapter 6, Table 12; FAO (1989), Irrigation Water Management Training Manual No. 4: Irrigation Scheduling, Annex I, Table 8; FAO (1998), Irrigation and Drainage Paper 56: Crop Evapotranspiration, chapter 1, units; Hunter Industries (2015), Drip Irrigation Design and Installation Guide (LIT-496), page 8; Hunter Industries (2026), Product Catalogue Vol. 41, EMEA metric edition, page 172.
What changes the run time
The soil does not change the day's water; it decides how often you give it: little and often on sandy soil, slowly on clay. Hunter's drip guide recommends pulsing, several shorter runs a day instead of one long one, for any dripline run longer than 12 minutes; a controller does it with extra start times or its cycle and soak setting.
Young plants need frequent watering, and NIHORT stresses watering straight after sowing or transplanting; then raise the run week by week with the crop factor. The need climbs as the dry season and the harmattan go on. In the rains, count the rain that soaks in and water only to top it up.
Water early in the morning, when it is least windy, as Hunter's design guide advises, and keep the water on the soil: NIHORT's fluted pumpkin guide says to water plants from the base to help control downy mildew.
Watering sandy, loamy and clay soilsPlanning for the dry seasonTopping up rain in the rainy season
Sources: Hunter Industries (2015), Drip Irrigation Design and Installation Guide (LIT-496), page 25; UF/IFAS Gardening Solutions, University of Florida (checked 2026), Watering the vegetable garden; NIHORT, National Horticultural Research Institute, Ibadan (posted 2020), Amaranth production guide; Onwuegbunam and others (2025), Actual crop coefficients and yield response factors of irrigated tomato in Afaka, Northwest Nigeria, Journal of Applied Life Sciences and Environment 58(1): study location and Tables 1a and 1b; NIHORT, National Horticultural Research Institute, Ibadan (posted 2020), Fluted pumpkin (ugu) production guide; Hunter Industries (2019), Residential Sprinkler System Design and Installation Guide (LIT-226), page 26.
Signs and checks
- Amaranth flowering early with few leaves: a sign of too little water, NIHORT says, though it also notes that most kinds flower when days are shorter than 12 hours.
- Tomato or pepper fruit with a dark, sunken patch at the flower end, or tomatoes cracking after rain: the crop guide explains both, and why steady watering matters.
- Plants wilting while the soil along the rows is dry: the run is too short, a row is blocked or cut, or the pressure has dropped.
- Water pooling on the bed or running off its edges: split the run into shorter pulses, and make sure the beds drain in the rains.
- Weekly, while the zone runs: every dripper wetting its patch of soil, no leaks, no rows pulled out of their fittings.
- Open and rinse the filter weekly to begin with, as the maintenance guide sets out, and at least once a year open the row ends and flush them until the water runs clear.
Irrigation maintenance through the seasonWatering signs in tomato and pepper
Sources: NIHORT, National Horticultural Research Institute, Ibadan (posted 2020), Amaranth production guide; Hunter Industries (2015), Drip Irrigation Design and Installation Guide (LIT-496), pages 24 to 26.
When to ask for a site-specific design
A few beds near a tap can be planned from this guide. Ask for a design when the garden is large or on a slope, when one tank or pump also serves the house, or when you are unsure of your pressure and flow. The water source, the tank's height, the bed sizes, the soil and how many beds one zone can water all depend on the site.
To design it, we need:
- Your state and town.
- The number and size of the beds, and what you plan to grow.
- Your soil, if you know it.
- The water source: the tank's size and height, a borehole or town supply, and any pump you have.
- Whether there is power near the garden, and a few photos of it.
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