Question 1

What decides the greenhouse specification before suppliers are contacted?

Accepted Answer

Five inputs decide almost everything else: crop and growing system, cultivated area and phasing, site climate extremes (temperature, humidity, wind and snow loads), water source and water analysis, and available electrical capacity. Structure type, covering, ventilation, screening, cooling, heating, irrigation, fertigation and automation follow from those inputs. Any of them left blank is filled in by each manufacturer with a different assumption, which is the usual reason two proposals for the 'same' greenhouse cannot be compared.

Question 2

Which packages should a greenhouse project be split into?

Accepted Answer

Structure and covering, foundations and civil works, ventilation, cooling and heating, screens, irrigation, fertigation equipment, water treatment, growing system or substrate, climate control and automation, electrical, energy and backup, packhouse and pre-cooling, then installation, commissioning, training and spare parts. Splitting the project this way exposes the packages a supplier has quietly excluded — civil works, electrical connection and water treatment are the three most often left out of a headline price.

Question 3

What are the real interface risks between greenhouse suppliers?

Accepted Answer

Water quality versus fertilizer solubility, irrigation flow versus dosing capacity, fertigation controller versus climate computer, drain recirculation versus disinfection, greenhouse climate design versus crop assumptions, and imported equipment versus local civil and electrical works. Each sits between two contracts, so it is nobody's scope unless the RFQ names an owner for it.

Question 4

What does a commercial greenhouse cost per square metre?

Accepted Answer

Indicative planning ranges: net house USD 8–20/m², single-span polytunnel 25–50, multi-span mid-tech 50–120, Venlo glass 150–350, and semi-closed controlled-environment 300–600. Climate severity typically adds 5–35%, site works 15–30% and financing costs 8–15%. These are feasibility figures for budgeting only — binding pricing comes from suppliers once site data and specification are fixed.

Question 5

When is a greenhouse project ready for supplier outreach?

Accepted Answer

When land control, water source and analysis, electrical capacity, crop plan, area, technology tier, budget band and target timeline are all documented, and one written specification exists that every supplier will quote against. Until then a requirement is scoped as 'early concept' or 'needs clarification' and is reviewed manually before anyone is contacted.

Question 6

How does a requirement move from enquiry to comparable offers?

Accepted Answer

One private brief is submitted; a sourcing specialist reviews it manually, identifies the missing information and normalises it into a single written specification; qualified manufacturers, integrators and EPC contractors are approached only after that internal approval; returned offers are normalised to the same scope, lead time and delivery terms so they can be compared line by line. No supplier is contacted automatically and no buyer contact details are released automatically.

Crop	N. Hemisphere — Greenhouse	N. Hemisphere — Open Field	S. Hemisphere — Greenhouse	S. Hemisphere — Open Field	Arid / Gulf
Tomato (greenhouse F1)	Aug–Oct sow → Sep–Jul harvest	Feb–Apr sow → Jul–Oct harvest	Feb–Apr sow → Mar–Jan harvest	Aug–Oct sow → Jan–Apr harvest	Sep–Nov sow (cool season)
Cucumber (parthenocarpic)	Year-round, 3 cycles	Apr–Jun sow → Jul–Sep harvest	Year-round, 3 cycles	Oct–Dec sow → Jan–Mar harvest	Oct–Mar (cool months)
Pepper (blocky bell)	Jul–Sep sow → Nov–Jul harvest	Mar–May sow → Aug–Oct harvest	Jan–Mar sow → May–Jan harvest	Sep–Nov sow → Jan–Apr harvest	Sep–Nov sow (cool season)
Watermelon	Feb–Mar sow → Jun–Aug harvest	Mar–May sow → Jul–Sep harvest	Aug–Sep sow → Dec–Feb harvest	Sep–Nov sow → Jan–Mar harvest	Sep–Nov sow (cool season harvest)
Melon (Galia / Charentais)	Feb–Mar sow → Jun–Aug harvest	Apr–Jun sow → Jul–Sep harvest	Aug–Sep sow → Dec–Feb harvest	Oct–Dec sow → Jan–Mar harvest	Sep–Nov sow
Lettuce (iceberg / romaine)	Sep–Mar (cool indoor)	Feb–Apr & Aug–Oct sow	Mar–Sep (cool indoor)	Aug–Oct & Feb–Apr sow	Oct–Feb sow
Onion (long-day storage)	—	Feb–Apr sow → Aug–Sep harvest	—	Aug–Oct sow → Feb–Mar harvest	Oct–Dec sow (short-day types)
Sweet corn F1	—	Apr–Jul sow → Jul–Oct harvest	—	Oct–Jan sow → Jan–Apr harvest	Sep–Nov sow
Alfalfa (perennial)	—	Mar–May or Aug–Sep seeding	—	Sep–Nov or Feb–Mar seeding	Oct–Dec seeding

Seasonal Planting Calendar

Seasonal Planting Calendar — Global Seed Sowing & Harvest

Frequently asked questions

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