Greenhouse and irrigation projects: calculate the farm before choosing suppliers

What does “calculate the farm first” mean?

It means defining the agronomic and economic result of the project — what you will grow, for which market, in what climate, with how much water, energy, fertilizer and labour, at what lifetime cost — before choosing a structure, an irrigation design or a manufacturer.

In procurement terms, it is the difference between buying equipment and buying an outcome. A supplier answers the question “what can I sell you?”. A farm calculation answers “what does this project need to work for fifteen or twenty years?”. The second question has to be answered first, otherwise the first one fills the gap.

Why a small planning effort changes lifetime economics

Most decisions that fix a project’s long-term cost are taken early: site orientation, gutter height, ventilation ratio, cooling and heating strategy, water source and treatment, zone sizes, pump duty point and the level of automation. Once steel is ordered and pipes are trenched, changing them is slow and expensive.

Planning time is small compared with the life of the asset. A few weeks spent on water analysis, climate data, crop schedules and cost scenarios cannot guarantee a result, but it removes the most common reasons projects underperform: an undersized cooling system, filtration that does not match the water, a structure chosen for a different climate, or a budget that ignores working capital.

The goal is not the cheapest equipment. It is the right price for the right specification and result. A lower quote that misses the specification is not a saving; a higher quote that adds unneeded features is not quality. You can only tell the difference once the specification exists.

Example roadmap: the project lifecycle stage by stage

SeedMatchGroup works as a procurement and project operating system across this lifecycle. Each stage produces a document the next stage depends on. Supplier vetting appears only at stage 8 — deliberately.

1. 1. Opportunity or problem

   Write one paragraph: the market, crop or problem (for example low marketable yield or water scarcity), and what success looks like in measurable terms.

2. 2. Search and shortlist options

   List realistic project types — multi-span greenhouse, net house, open-field drip, hydroponics — and discard those that do not fit the climate, market or capital.

3. 3. Discovery and requirements

   Collect site data: area, topography, climate records, water source and analysis, power availability, access, permits and labour.

4. 4. Feasibility calculations

   Run peak water demand, climate load, fertilizer budget and production assumptions. Use practical calculators, then check them against local data.

5. 5. Budget, ROI and scenarios

   Build CAPEX, OPEX, revenue and payback with a base case and at least two downside cases (lower price, lower yield, higher energy).

6. 6. Design, specification and URS

   Turn the numbers into a user requirement specification: performance targets, design conditions, interfaces, documentation and acceptance tests.

7. 7. Planning and project management

   Define the schedule, responsibilities, decision gates, budget control and who signs off each package.

8. 8. Supplier vetting (only now)

   Identify manufacturers whose capability matches the URS: references at similar scale and climate, local service, spares and documentation.

9. 9. Quotation comparison

   Compare proposals line by line against the URS — included scope, exclusions, performance guarantees offered by the supplier, lead time and lifecycle cost.

10. 10. Negotiation

    Negotiate scope, payment milestones, delivery terms, warranty and acceptance criteria — not only the headline price.

11. 11. Execution support

    Track delivery, installation, commissioning and handover against the specification and the acceptance tests.

12. 12. Risk reduction after start-up

    Measure actual water, energy and yield against the plan and correct early, while warranty and support are active.

Practical formulas with their assumptions

These are planning formulas, not engineering design. They help you size the question before a specialist sizes the system.

Worked example (illustrative assumptions only)

A hypothetical 2-hectare greenhouse tomato project, used only to show how the formulas connect. None of these values is a benchmark.

The lesson is in the sensitivity: a 10% lower price moves payback by about 2.5 years in this example. That is why price, yield and energy scenarios belong in the plan before supplier selection, and why a cheaper structure that raises OPEX or lowers marketable yield can cost more over the project life.

Worksheet: fill this in before requesting quotes

Copy these lines into your project file. Every blank is a question a supplier would otherwise answer for you.

1. Crop(s), varieties, planting calendar and target market/buyer specification
2. Site: area (ha), coordinates, topography, soil type, access and permits status
3. Climate: monthly max/min temperature, humidity, radiation, wind and design extremes
4. Water: source, available flow (m³/h), storage, full water analysis (EC, pH, bicarbonates, Na, Cl, B, Fe, Mn, TSS)
5. Peak daily water demand (m³/day) and number of irrigation zones/shifts
6. Energy: grid capacity, tariff, backup power, heating or cooling fuel
7. Fertilizer strategy: open or recirculating system, annual budget estimate
8. Production assumptions: marketable yield range, net price range, seasons per year
9. CAPEX ceiling, OPEX estimate, working capital and financing route
10. Required automation level, data/traceability needs and local service expectations
11. Acceptance tests: what performance must be demonstrated at handover

Supplier-first versus farm-first procurement

Mistakes to avoid

• Asking for “a price per square metre” before the climate, crop and water are defined.
• Designing irrigation without a recent laboratory water analysis.
• Using gross yield and retail prices in the business case.
• Leaving out working capital, first-season ramp-up and replacement parts.
• Comparing quotes that include different scope, exclusions or warranty terms.
• Choosing automation for its features rather than for the decisions the grower must make.
• Treating a calculator output as a design. It is a planning estimate to be verified.

What is accessible without upfront cost

Our planning guides, calculators and project wizard are free to use, and submitting a project request is free for buyers.

SeedMatchGroup focuses on commercial projects, typically from USD 250,000. A sourcing specialist reviews each brief before any supplier is approached; supplier identities and introductions are handled manually after that review.

Specialist consulting, engineering design or project management beyond this guidance may be scoped separately — we confirm what applies to your project in writing rather than assuming it is included.

Frequently asked questions

Sources

• FAO Irrigation and Drainage Paper 56 — Crop evapotranspiration
• FAO — Good Agricultural Practices for greenhouse vegetable crops (Plant Production and Protection Paper 217)