Watering a lawn: sprays, rotors and run times.
A lawn stays even only if every part of it gets the same water. Before the dry season you are choosing the sprinklers, their spacing and how long each zone runs. This guide covers the grasses used for lawns in Nigeria, the three kinds of lawn sprinkler, a catch-can test, and a run time worked from the weather.
Written for homeowners and estate and facility managers. Updated .
Key points
- Give the lawn zones of its own, split by sun and shade, and never put fixed sprays on one valve with MP Rotators or rotors.
- Space the heads head to head, so each one throws its water all the way to the next.
- Measure what each zone puts down with a catch-can test before you trust a run time.
- Work the run time out from the weather, the grass and the nozzle, then water early in the morning, deeply and less often.
- In the rains let a rain sensor stop the watering, and watch the lawn: footprints that stay mean it needs water sooner.
On this page
Why the lawn gets zones of its own
A hydrozone is a group of plants with similar water needs and rooting depth, watered together by one valve with its own run time. California's landscape water rules, which this series follows for the idea, define it so, and class lawn grass as shallow to moderately rooted, shrubs as moderate and trees as deep.
So the lawn never shares a valve with beds, hedges or trees: they need other run times and are usually watered by drip, and shrubs and trees root deeper.
Split the lawn itself where it differs: Hunter draws zone lines by sun and plant type, and the University of California's lawn guide says to use less water in shade. Sunny and shaded lawn get a zone each.
Home garden and lawn irrigationEstate and commercial landscape irrigation
Sources: California Code of Regulations, Title 23, section 490.2 (2025), Model Water Efficient Landscape Ordinance: definitions of hydrozone and plant factor; Hunter Industries (2019), Residential Sprinkler System Design and Installation Guide (LIT-226), metric edition, page 9; UC IPM (2017), UC Guide to Healthy Lawns: Irrigation scheduling.
Lawn grasses in Nigeria
Ornamental horticulture notes from the Federal University of Agriculture, Abeokuta, say few lawn grasses are commonly used in Nigeria. Bahama grass (Cynodon dactylon, the bermudagrass of American guides) takes trampling, covers most football pitches and large lawns, and needs watering more often in the dry season. Carpet grass (Axonopus compressus) suits ground with a high water table and needs more frequent watering, mowing and feeding. Zoysia grass (Zoysia tenuifolia) is slow to cover but grows well in shade, with high, regular care.
A survey of 110 florists in Lagos, Ibadan, Port Harcourt and Benin found Port Harcourt grass most preferred, then a Zoysia, then Bahama grass, and named poor watering facilities in the dry season among the constraints.
UC's lawn guide says an established lawn's roots generally reach 15 to 20 cm, some warm-season grasses deeper: the depth each watering should reach.
Sources: Federal University of Agriculture, Abeokuta, HRT 507 Ornamental Horticulture lecture notes (Aiyelaagbe and Olosunde), pages 3 to 5: lawn grasses; Akintoye and others (2018), Prospects and challenges of lawn maintenance in Nigeria, Acta Horticulturae 1225: abstract; UC IPM (2017), UC Guide to Healthy Lawns: Irrigation scheduling.
How much water the grass needs
Water need in a day, in mm, is ETo times a plant factor. ETo is the weather's drying power: what a well-watered field of grass loses in a day.
For a dry-season month this series uses an ETo of 6 mm a day. A field study at Afaka, Kaduna State, worked out 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. That fits the north and centre; the south and the rains run lower.
The plant factor is the share of ETo a plant uses. California's rules sort plants into very low (less than 0.1), low (0.1 to 0.3), moderate (0.4 to 0.6) and high (0.7 to 1.0). The classes come from California and are a guide only.
For warm-season grasses such as Bahama grass (bermudagrass) and zoysia, UC's WUCOLS list gives 60 percent of ETo, a factor of 0.6 at the top of the moderate class; cool-season grasses need 80 percent. UC's monthly factors for warm-season lawns in California run from about 0.54 to 0.79 through the year: start from 0.6, then watch the lawn and adjust.
Some sprinkler water drifts, evaporates or lands unevenly. This series counts 75 percent as reaching the roots, the top of USDA's 60 to 75 percent for fixed sprinklers, fitting a well-designed head-to-head layout, so sprinklers put down the need divided by 0.75.
Irrigating tomatoes, peppers and onions: ETo explained
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; California Code of Regulations, Title 23, section 490.2 (2025), Model Water Efficient Landscape Ordinance: definitions of hydrozone and plant factor; WUCOLS IV, University of California, Plant Factors for Turfgrasses, from Harivandi (2009), UC ANR Publication 8395; UC ANR Center for Landscape and Urban Horticulture, Turfgrass Crop Coefficients (Kc), Table 1; USDA-NRCS (1997), National Engineering Handbook Part 652: Irrigation Guide, chapter 6, Table 6-4.
Sprays, MP Rotators or rotors
Three kinds of pop-up head suit lawns, each rising to water and dropping back level with the grass. They differ in throw and in precipitation rate: how fast they put water down, in mm an hour.
Hunter says fixed sprays must never share a zone with rotors or rotating nozzles such as MP Rotators: the fast sprays would flood their part before the rest had enough. Most soils take in less than 25 mm an hour, Hunter's catalogue adds, so a slow rate soaks in where a fast one runs off.
Pressure is how hard the water pushes inside the pipe, measured in bar. Hunter pairs MP Rotators with a Pro-Spray body regulated to 2.8 bar (the PRS40) for their full throw, or to 2.1 bar (the PRS30) for the shortest; the regulated body in our store is the PRS30. Each zone has its own valve, in a valve box.
| Head | How far it throws | Water it puts down | Suits |
|---|---|---|---|
| Fixed spray nozzle on a Pro-Spray body | 1.5 to 5.2 m | About 40 to 50 mm an hour | Small or oddly shaped lawns |
| MP Rotator nozzle on a Pro-Spray body | 2.5 to 10.7 m; to 9.1 m with our store's nozzles | About 10 mm an hour | Small and medium lawns, slopes and clay |
| Rotor, such as the PGP Ultra or I-20 | 4.9 to 14 m | About 10 mm an hour | Lawns of 8 by 8 m and more; the I-20's check valve suits slopes |
Hunter Pro-Spray pop-up bodyHunter MP Rotator nozzleHunter PGP Ultra rotorHunter I-20 rotorHunter PGV zone valve
Sources: Hunter Industries (2019), Residential Sprinkler System Design and Installation Guide (LIT-226), metric edition, pages 6 and 17; Hunter Industries (2026), Product Catalogue Vol. 41, EMEA metric edition, pages 22, 23, 49, 52, 76 and 77.
Head to head, step by step
Head to head means each sprinkler throws its water all the way to the next. Without that overlap, dry patches show between heads however long the zone runs; UC notes that brown spots are often down to uneven coverage.
Sprinklers struggle to water a narrow strip beside a wall or path without wetting the paving; Hunter lists drip for narrow areas, so consider a groundcover bed on drip. On a slope, use heads with a check valve, which stops the water in the pipe draining out of the lowest heads after each run. Hunter's guide places heads like this:
- Draw the lawn to scale and put a quarter-circle head in each corner.
- Where corner heads do not reach each other, add half-circle heads along the edges.
- Where edge heads do not reach across, add full-circle heads in the middle.
- Break a curved edge into short straight lines; adjustable-arc nozzles follow the curve.
- Stay within the maker's chart: Hunter spaces small-area heads 3 to 5 m apart and rotors 8 to 12 m apart.
Watering groundcovers: drip grid or low sprays?
Sources: Hunter Industries (2019), Residential Sprinkler System Design and Installation Guide (LIT-226), metric edition, pages 8 and 29; UC IPM (2017), UC Guide to Healthy Lawns: How to water; Hunter Industries (2015), Drip Irrigation Design and Installation Guide (LIT-496), page 6.
Measure what a zone puts down
The maker's rate assumes the right spacing and pressure. A catch-can test shows what your zone really puts down, and how evenly. The University of Minnesota's method:
- First fix broken or tilted heads, low pressure and water landing on paths.
- Set out at least 20 identical cans in an even grid: about 1.5 to 2.4 m apart for sprays, 3 to 6 m for rotors.
- Run the zone for 30 to 60 minutes.
- Measure the water in each can, in mm, with a ruler.
- The rate is the average depth divided by the hours run: an average of 5 mm in 30 minutes is 10 mm an hour.
- For evenness, divide the average of the lowest quarter of the cans by the average of all of them. Below 60 percent, fix the layout before you set run times.
- A pop-up head, risen while the zone runs; it drops back level with the grass after
- Each head throws water all the way to the other one: head-to-head spacing
- Catch cans set out between the heads, all the same size, to measure what the zone puts down
- The cans that catch least show where the lawn gets least water
- The grass roots, in the top of the soil: each watering should wet them to the bottom
- The pipe under the lawn, from the zone's own valve in its valve box
- A screwdriver pushed in after watering: it slides through wet soil and stops at dry soil
Minnesota advises a test every spring; in Nigeria, test at the start of each dry season.
Source: University of Minnesota Extension (reviewed 2024), Auditing home lawn irrigation systems.
Run times: a worked example
Water an established lawn deeply and less often: UC says light, frequent sprinkling keeps roots shallow, and that a lawn needs water when the top 5 cm of soil has dried. Water early in the morning, the least windy time with the most pressure, Hunter says, not in the evening, which leaves grass wet overnight.
Hunter X-Core controller, with Cycle and Soak
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; WUCOLS IV, University of California, Plant Factors for Turfgrasses, from Harivandi (2009), UC ANR Publication 8395; USDA-NRCS (1997), National Engineering Handbook Part 652: Irrigation Guide, chapter 6, Table 6-4; Hunter Industries (2026), Product Catalogue Vol. 41, EMEA metric edition, pages 49, 52, 77 and 105; Hunter Industries (2019), Residential Sprinkler System Design and Installation Guide (LIT-226), metric edition, page 26; UC IPM (2017), UC Guide to Healthy Lawns: How to water; UC IPM (2017), UC Guide to Healthy Lawns: When to water; UC IPM (2017), UC Guide to Healthy Lawns: Irrigation scheduling.
What changes the run time
- Soil. Clay takes water in slowly: shorter runs, more of them, on fewer days. Sand drains fast and holds little: water little and often, on more days, with no need to split the runs.
- A new lawn. Light, frequent watering helps only while new grass roots in the very top of the soil; then water deeply and less often.
- Shade. A shaded lawn needs less water, so it gets its own zone and shorter runs.
- The dry season and the harmattan. Plan the whole season with the dry-season guide.
- The rains. A rain sensor such as the Mini-Clik halts scheduled watering once a set amount of rain has fallen, and lets the controller water again as it dries. Between storms, the rainy-season guide shows when to top up.
Watering sandy, loamy and clay soilsPlanning dry-season irrigation in NigeriaSupplemental irrigation in the rainy seasonHunter Mini-Clik rain sensor
Sources: Hunter Industries (2019), Residential Sprinkler System Design and Installation Guide (LIT-226), metric edition, page 26; UC IPM (2017), UC Guide to Healthy Lawns: How to water; UC IPM (2017), UC Guide to Healthy Lawns: Irrigation scheduling; Hunter Industries (2026), Product Catalogue Vol. 41, EMEA metric edition, page 155; Hunter Industries (checked 2026), Mini-Clik rain sensor: product page.
Signs and checks
- Footprints that stay, a change of colour or wilting: the lawn waited too long for water.
- Brown patches in a pattern, often between heads: uneven coverage. Check the heads before you add minutes.
- Puddles, runoff onto paths, soggy ground or far more mowing: too much water, or water put down faster than the soil takes it in.
- After watering, a screwdriver slides in to the depth of the roots and stops where the soil is dry.
- Every head pops up, turns if it should, reaches the next and sits level with the grass, nozzle clean.
- Arcs set so the water stays off walls, paths and windows.
- Each zone run by hand now and then, and a catch-can test at the start of each dry season.
Irrigation maintenance through the season
Sources: UC IPM (2017), UC Guide to Healthy Lawns: When to water; UC IPM (2017), UC Guide to Healthy Lawns: How to water; University of Minnesota Extension (reviewed 2024), Auditing home lawn irrigation systems; Hunter Industries (2019), Residential Sprinkler System Design and Installation Guide (LIT-226), metric edition, page 26.
When to ask for a design
A lawn layout depends on the site: the water the source gives and its pressure, which set how many heads one zone can run; the lawn's shape, slopes and shade; and the soil. We design and supply lawn systems, and installation can be quoted. To plan one, send us:
- State and town or local government area
- Crop, or the type of site
- Area, in hectares, acres or square metres
- Where the water comes from, and how much you think you have
- How you pump today, and what powers the pump
- When you want the system working
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