Is irrigation worth it for your farm, garden or estate?
Before choosing drip or sprinklers, decide whether irrigation is worth paying for on your site at all. This guide shows where Nigeria's rain leaves gaps, how much water a small plot needs when it is watered by hand, and how to set the benefits against the costs using your own figures.
Written for farmers, greenhouse and nursery growers, homeowners and estate and facility managers.
Where the rain leaves gaps
Nigeria's rainy season is long in the south and short in the north. FAO's country profile gives a rainy season of 9 to 12 months in the south and 2 to 3 months in the north, with most of the rain falling from June to September. Outside the rains, a crop, a lawn or a hedge has only the water you give it.
The total is only part of the story. For most of the country, the same profile says the bigger problems are when and where the rain falls, and how little it can be relied on.
NiMet's long-term averages show the contrast. At Kano almost no rain falls from November to March, while at Lagos some rain falls in every month, least in December and January.
The dry months at ten weather stations
Sources: FAO (2016), AQUASTAT Country Profile: Nigeria, climate, water resources and irrigation sections; NiMet and WMO (2026), World Weather Information Service: Kano climate; NiMet and WMO (2026), World Weather Information Service: Lagos climate.
Dry spells after the rains start
A dry spell is a run of days without useful rain inside the rainy season. The rains do not start on a fixed date. A study of five weather stations in the south-west, led from the Federal University of Agriculture, Abeokuta, notes that the rains start early in some years and late in others, and that a false start can be followed by a dry spell of two weeks or more, which may harm germination and young plants.
In the north-central states, a NiMet study of daily rain from 1981 to 2020 at eight weather stations recorded dry spells of up to 25 days in the first 50 days after the rains began. It found the spells near the end of the season more severe than those at the start. When such breaks run long, plants may wilt or die.
A crop sown on the first rains, or a lawn or hedge planted at the start of the season, is at risk, and so is a crop still growing when a dry spell comes near the end of the season. Water you can give for those weeks carries it through.
Irrigation in the rainy season
Sources: Sobowale, Sajo and Ayodele (2016), Analysis of onset and cessation of rainfall in southwest Nigeria, Hungarian Agricultural Engineering 30: introduction; Usman and Mamman (2022), Spatio-temporal analysis of dry spell for agricultural decision support in north-central Nigeria, Environmental and Earth Sciences Research Journal 9(1): abstract, introduction and results.
A year of rain, and where irrigation fits
The shape of the year changes from south to north. Near the coast rain falls in most months; in the far north the rains last only a few months, so the dry months at each end of the year grow longer.
- The twelve months of the year, January on the left and December on the right
- The dry months: sun, and little or no rain
- The rains start, often with stops and starts in the first weeks
- A dry spell after the rains have started: young plants can wilt
- The main rains, heaviest in the middle months
- The rains end and the dry season comes back
- A drip line waters the crop through the dry months, and through a dry spell in the rains
Sources: FAO (1994), Aquatic plants and wetland wildlife resources of Nigeria, CIFA Occasional Paper 21: sections 1.1, Climate, and 1.4, Water resources; FAO (2016), AQUASTAT Country Profile: Nigeria, climate, water resources and irrigation sections.
What irrigation changes
Irrigation does not make rain, and it does not fix poor soil, pests or a weak water source. What it changes is when you can grow, and who carries the water.
- You can grow in the dry season. FAO's profile describes small farms on fadama land, the low-lying land along rivers where the water table is high, growing vegetables and wheat in the dry season with pumps and tube wells.
- You choose the planting date instead of waiting for the rains, so you can plan when a crop is ready and when you will need workers.
- A rainy-season crop can be carried through a dry spell instead of being replanted.
- Gardens, lawns and estate planting can be kept growing through the dry months.
- The work changes: less carrying of water, and more checking of filters, pipes and the crop.
Source: FAO (2016), AQUASTAT Country Profile: Nigeria, climate, water resources and irrigation sections.
The labour of watering by hand
Many farm families in Nigeria have long grown small dry-season plots on fadama land with water drawn by hand from shallow wells or streams, and FAO notes that all fadama farming takes a lot of labour. The example shows how much water one small plot needs on a hot day.
Sources: FAO (1986), Irrigation Water Management Training Manual No. 3: Irrigation Water Needs, Part II, chapter 3, Tables 5 and 8; FAO (1986), Irrigation Water Management Training Manual No. 3: Irrigation Water Needs, Part II, chapter 2, Table 1; FAO (1998), Irrigation and Drainage Paper 56: Crop evapotranspiration, chapter 1, Units; FAO (2016), AQUASTAT Country Profile: Nigeria, climate, water resources and irrigation sections.
Benefits and costs to count
List what irrigation would add and what it would cost on your site, as items you can put your own figures against. Do not leave an item out because it is hard to put a figure on: note it, and come back to it.
NRCS, the United States Department of Agriculture's conservation service, advises that a comparison of irrigation designs should count the running costs as well as the equipment and its installation.
| Item | Benefit or cost | How to count it |
|---|---|---|
| A crop or planting in the dry months | Benefit | What you could grow or keep alive without rain, on how much land, and when it would be ready |
| Crops carried through dry spells | Benefit | How often a dry spell has cost you a planting or a crop, from your own records or your neighbours' |
| Planting when you choose | Benefit | Whether a harvest outside the main season suits your buyers, your workers or your own use |
| Hours of hand watering | Benefit | Hours a day now spent carrying water, and what that time and those workers could do instead |
| Equipment and installation | Cost | Each line of a written quotation: pump, filter, pipes, drip lines or sprinklers, controller, and the work to install them |
| Water source works | Cost | A borehole, well, tank or pond, if the present source cannot meet the need |
| Power or fuel | Cost | Hours of pumping a day, times what the pump draws or burns, over the season |
| Upkeep and spares | Cost | Filter cleaning, flushing, parts that wear, and repairs, each season |
| Running the system | Cost | Who opens the valves, checks the filters and watches the crop, and for how many hours |
| Learning and support | Cost | Training for whoever runs it, and how far away help is when something breaks |
Weigh it up, step by step
A partial budget is the method farm extension services use to judge a single change on a farm, and it works for a garden or an estate too. Penn State Extension sets it out in seven steps; in short:
- Describe the change in one line, for example: drip irrigation on one hectare of peppers through the dry season.
- List what you would gain: new income, and costs you would no longer have, such as paid hands for watering.
- List what you would give up: new costs, and any income you would lose, such as land taken by a tank or pond.
- Put your own figures against each line, from written quotations and your own records.
- Count the cost of equipment year by year over its working life, not all against one season. For effects more than a year or two ahead, Penn State points to a net present value approach, which counts money in later years as worth less than money now.
- Add up each side, and set what you would gain against what you would give up.
- Add what does not fit in figures: less heavy work, a steadier supply for buyers, the risk of the water source failing, and the time it takes to learn the system.
Signs it is worth a closer look
- Dry spells have cost you a planting or a crop in recent seasons
- Your land sits idle through the dry months, or your garden dies back every year
- You or your workers spend hours a day carrying water
- You have a water source that lasts through the dry season, or could have one
- There is a market or a use for what you could grow or keep green outside the rains
- Someone on site can run the system and look after it
When to wait
- The water source has not been measured in the dry season, or is known to run short: sort out the water first.
- No one will be on site to run and look after the system.
- The crop, the market or the land is still uncertain: a small first stage can test it before a larger system.
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