Greenhouse & Protected Cultivation Tools

It depends on your climate and crop value. A naturally-ventilated polyhouse (polyethylene film over a steel frame) suits most warm regions and high-value vegetables and cut flowers. A net house (insect or shade net only) is cheaper, cuts pest pressure and heat but gives no rain protection. A shade house with 35–50% net suits nursery and shade-loving crops. A fully climate-controlled glass or polycarbonate greenhouse only pays in cold or extreme climates or for very high-value crops. Start with the polyhouse ROI tool to see which structure your crop and price premium can actually fund.

Shade nets are sold by their shade factor — typically 25%, 35%, 50% or 75%. Leafy greens and nursery seedlings usually want 35–50%; ferns, orchids and some ornamentals 50–75%; fruiting vegetables often just 25–35% to cut peak heat without starving them of light. For area, measure the roof plus the gable ends and side walls and add 8–12% for overlap and fixing. The Greenhouse & Shade-Net Area tool does the full surface and overlap maths for you.

UV-stabilised greenhouse polyethylene film (typically 200 micron / 800 gauge) lasts about 3–4 years before it clouds and weakens; premium multi-layer films can reach 4–5 years. Shade nets last roughly 5–7 years, polycarbonate sheet 10–15 years, and glass effectively indefinitely. Budget for re-covering film every few years as a running cost, not a one-off — the covering-life table on this page lists typical figures.

Under cover you almost always fertigate through drip, which is why protected crops use 30–50% less water than flood or furrow irrigation and place nutrients exactly at the root zone. A typical fertigation solution runs at an EC of about 1.5–2.5 dS/m for fruiting vegetables. Use the drip-design tools to size the lines, then the fertigation EC/ppm and injection-recipe tools to mix the feed to the right strength.

Peninsula (finger) benching with a central aisle commonly reaches 70–80% floor-space use, against roughly 50–65% for simple longitudinal benches with side walkways, and rolling benches can exceed 85%. Keep main aisles 60–90 cm wide for carts. The Greenhouse Bench Layout tool returns the bench count, growing area and the exact utilisation percentage for your house and bench size.

Fertigation is delivering soluble fertiliser dissolved in the irrigation water through the drip system, so the crop is fed little and often instead of in big soil dressings. Under cover there is no rain to leach nutrients and the root zone is small, so precise, frequent feeding through drip gives faster growth, better quality and far less waste. Mix to a target EC and nutrient ratio with the fertigation and hydroponic-nutrient tools, then inject it safely with a backflow-protected dosing setup.

A naturally-ventilated polyhouse in India runs roughly Rs 800–1,200 per m² to build (less for a net house, far more for a fan-and-pad climate-controlled house). With a high-value crop such as coloured capsicum, gerbera or exotic cucumber and a typical price premium, payback is often 3–5 years, helped by subsidies of up to 50% under schemes like MIDH. The Polyhouse ROI tool turns your build cost, crop and price into a payback period and annual profit.

Yes — a closed film house can run 8–15°C hotter than outside on a sunny day, which stresses most crops above about 35°C. Naturally-ventilated houses rely on roof and side vents plus an internal shade net or whitewash; warmer climates add foggers or fan-and-pad evaporative cooling, which can drop air temperature several degrees toward the wet-bulb. Use the heat-stress and evaporative-cooling tools to decide how much shade and cooling your site needs.

Yes — soilless culture in cocopeat grow-bags, perlite or pure hydroponics (NFT, drip-to-bag, deep-water) is common under cover because it removes soil-borne disease and gives total control of the nutrient solution. You feed entirely by fertigation at a controlled EC and pH. Use the hydroponic-nutrient and potting/growing-mix tools to build the feed and the media, and the rack-layout tool if you go vertical.

Protected crops are usually grown at higher density than open field because every metre is expensive and the climate is controlled — for example high-wire tomato or cucumber at roughly 2.5–3.5 plants per m². Lay out paired rows with a wide service aisle, train vertically on wire, and size your seedling raising to match. The plant-spacing, trellis-wire and transplant-age tools size the population, support and nursery schedule together.

The structure itself is the first line of defence: a 40-mesh insect net on vents and doors excludes whiteflies, thrips and leaf miners, and a double-door entry stops them slipping in. Combine that with sticky traps, strict sanitation and a clean nursery. Because the canopy is dense and indoor, even spacing of micro-sprinklers or drip keeps humidity even and reduces disease — the coverage-uniformity tools help you avoid wet, disease-prone pockets.

Vapour-pressure deficit (VPD) measures how 'thirsty' the air is — it combines temperature and humidity into one number that drives how fast plants transpire. Most greenhouse crops are happiest at a VPD of roughly 0.8–1.2 kPa; too low (humid, low VPD) invites fungal disease and weak growth, too high (hot, dry) closes stomata and stalls the crop. The Humidity & VPD tool converts your house temperature and humidity into VPD so you can vent, fog or shade to stay in the sweet spot.