Maharashtra SSC Green House Grade cheat sheet

Slope: choose 0.5–1% grade for drainage; slopes above 2% need terracing and raise levelling cost by 15–25%.

Orientation of the long axis for light: north–south ridge in low-latitude Maharashtra reduces midday shading between bays; east–west suits winter-light-limited crops.

Wind: design for basic wind speed of 39–44 m/s in coastal Konkan and 33–39 m/s in Vidarbha/Marathwada per IS 875 Part 3 zones.

Soil bearing capacity: minimum 100 kN/m2 for polyhouse footings; avoid black cotton soil with >40% clay due to swell–shrink movement.

Water: confirm 5–8 L/plant/day for tomato in summer; a 1,000 m2 unit needs roughly 5,000–8,000 L/day at peak.

Distance from coast: sites within 5 km face salt spray and corrosion; specify hot-dip galvanised (80–120 micron) or GI + powder-coated structures.

Avoid flood plains and low-lying plots; keep floor level at least 0.5 m above the highest recorded flood mark.

Check power supply (3-phase), all-weather access road, and market distance; produce loses 1–2% quality per day of transit delay.

Sunlight: select sites receiving 6+ hours direct sun in winter; avoid shading from trees within 15 m of the structure.

Span categories: low-cost tunnel 4–5 m, medium polyhouse 6–9 m, wide-span 12–18 m; wider spans need stronger trusses and higher cost per m2.

Gutter height: 3.0–4.0 m for tomato/cucumber; below 2.5 m causes heat build-up and labour difficulty.

Roof pitch: 20–30 degrees for natural ventilation and condensation run-off; flatter roofs drip onto the crop.

Snow/wind load: IS 875 Part 3 and Part 4 govern design; Maharashtra generally no snow load, but wind bracing is mandatory.

Structural members: GI pipe 50–60 mm OD for arches, 25–32 mm for purlins; spacing of arches 1.0–1.2 m for film covers.

Insect-proof screen houses use 40–50 mesh; the structure must resist screen wind pressure (higher than film).

Foundation: concrete pedestals 30x30x60 cm for each arch column; anchor with base plates and bolts.

Truss design: triangular or bow-string trusses at 3–4 m spacing support the gutter and roof film in wide-span houses.

UV-stabilised LDPE film: 200 micron, life 2–3 years; 800-gauge (200 micron) film transmits 85–90% PAR when new.

Anti-drip and anti-fog additives prevent condensation droplets; IR-blocking films reduce night heat loss by 15–20%.

Polycarbonate twin-wall: 6–10 mm, life 10–15 years, light transmission 75–80%, better insulation (U-value ~3 W/m2K).

Glass: 4–5 mm tempered, transmission 90%+, life 20+ years, high cost; used in high-tech projects.

Shade nets: 35–50% for summer tomato, 50–75% for nursery and orchid; colour black or green affects light quality slightly.

Diffused film increases light scattering, improving lower-canopy light by 10–20% and reducing sunburn.

Film replacement rule: when transmission falls below 70% of new value or yellowing/tearing appears, replace.

Hail net (5x5 mm mesh) over film protects against hail and reduces film damage in Vidarbha storms.

Film fixing: use aluminium profile + spring wire lock or zig-zag wire + channel; spacing of fixing channels 0.5–0.75 m.

Overlap film edges by 10–15 cm and fix on the leeward side to prevent wind peel-off.

Gutter and roof junctions need anti-leak tapes or butyl sealant; leaks cause localised disease foci.

Screen houses: 40-mesh excludes whitefly and thrips; 50-mesh excludes mites but reduces ventilation by 30–40%.

Roll-up side curtains: 1.0–1.5 m height, manually or motor-driven, operated morning (open) and evening (close).

Thermal screens (aluminised) reduce night heat loss by 30–40% and are drawn at sunset, retracted at sunrise.

Double-layer inflated film reduces heat loss by 30–40% and is used in high-altitude or winter crops.

Inspect cover monthly for tears; a 1 cm tear expands under wind within days; patch with UV tape.

Optimum temperature ranges: tomato 20–28°C day / 15–18°C night; cucumber 22–30°C; capsicum 20–25°C.

Above 32°C, pollen viability drops sharply; above 35°C fruit set fails in tomato; use shade + fogging + ventilation.

Relative humidity target 60–80%; above 90% for more than 4 h triggers Botrytis and downy mildew.

Vapour pressure deficit (VPD) 0.5–1.2 kPa is ideal; VPD >2 kPa causes stomatal closure and blossom-end rot risk.

Natural ventilation: roof vents 15–20% of floor area plus side vents 15–20%; total vent area 25–35%.

Fan-and-pad cooling: pad efficiency 70–85%; airflow 0.03–0.05 m3/s per m2 of floor; temperature drop 6–10°C in dry heat.

Fogging systems: 5–10 micron droplets; run at VPD >1.5 kPa; risk of leaf wetness if run at low VPD.

Thermal screen and heating: use only where night temperature <12°C; Maharashtra plains rarely need active heating.

CO2 enrichment to 700–1,000 ppm raises yield 10–20% in sealed houses; not viable in naturally ventilated polyhouses.

Drip emitter spacing 30–40 cm, discharge 2–4 L/h; one drip line per row for tomato, two for cucumber on beds.

Crop water requirement (ETc) = ETo × Kc; tomato Kc 0.6 (initial), 1.15 (mid), 0.8 (late).

Fertigation: stock solution A (calcium nitrate + iron chelate) and B (potassium + phosphate + micronutrients) kept separate to avoid precipitation.

EC of nutrient solution 1.8–2.5 dS/m for tomato; pH 5.5–6.5; check daily with EC and pH meters.

Leaching fraction 20–30% in soilless culture; in soil, 10–15% to control salt build-up.

Water quality: EC <0.75 dS/m ideal; above 1.5 dS/m requires blending or crop change; sodium <3 meq/L.

Filtration: sand filter + 120-mesh screen; drip lines clog with algae if water is unfiltered.

Irrigation scheduling: 2–4 pulses/day in summer, 1–2 in winter; avoid late evening irrigation to reduce night humidity.

Water use efficiency: drip + mulch saves 40–50% water versus furrow; greenhouse drip achieves 8–12 kg tomato per m3.

Open system: nutrient solution drains away (10–30% leachate); closed system recirculates with disinfection (UV or slow sand filter).

Coir pith: EC must be <0.5 dS/m after buffering with calcium nitrate; untreated coir has high potassium and sodium.

Rockwool slabs: 7.5–10 cm thick, 90–100 cm long; buffered to pH 5.5 before use; one slab for 2–3 plants.

Perlite and vermiculite mixes: 50:50 for propagation; perlite improves aeration, vermiculite holds water and potassium.

NFT: channel slope 1–2%, flow 1–2 L/min per channel; root mat clogging risk in warm water above 25°C.

Dutch bucket / bag culture: 8–10 L substrate per plant; drain holes at the base; used for tomato, capsicum, cucumber.

Substrate EC target 2.0–2.5 dS/m for tomato; pH 5.5–6.0; measure by 1:1.5 water extract or pour-through method.

Reuse of substrate: steam or solarise between crops; coir can be reused 2–3 seasons with leaching and buffering.

Hoagland solution (full strength): N 210, P 31, K 234, Ca 200, Mg 48, S 64 ppm; micronutrients Fe-EDTA 2.5–5 ppm, Mn 0.5, Zn 0.05, Cu 0.02, B 0.5, Mo 0.01 ppm.

Macronutrient ratios for tomato: N:K ratio 1:1.2 to 1:1.5; high K during fruiting, high N during vegetative stage.

Calcium deficiency causes blossom-end rot; ensure Ca >150 ppm and stable moisture; Ca moves with transpiration.

Nitrogen form: 10–20% ammonium, rest nitrate; high ammonium causes root damage and blossom-end rot.

Iron chelate (Fe-EDTA/Fe-DTPA) at 2–5 ppm; deficiency shows as interveinal chlorosis on young leaves.

Boron toxicity risk above 1 ppm in irrigation water; boron deficiency causes hollow stem and distorted growing point.

Solution pH: 5.5–6.0 for soilless; below 5.0 causes Ca/Mg leaching and micronutrient toxicity.

Prepare stock solutions at 100× concentration; inject at 1:100 ratio; keep tanks shaded and covered.

Key pests: whitefly, thrips, two-spotted spider mite, leaf miner, fruit borer; whitefly vectors tomato leaf curl virus.

Yellow sticky traps at 10–15 per 1,000 m2 for whitefly; blue traps for thrips; monitor weekly.

Biological control: Encarsia formosa for whitefly, Phytoseiulus persimilis for spider mite, Trichogramma for fruit borer.

Pheromone traps: 20–25/ha for Helicoverpa; 10–15/ha for Tuta absoluta where present.

Chemical rotation: rotate modes of action (IRAC groups); do not repeat the same group in consecutive sprays.

Pre-harvest interval (PHI): follow label; e.g., imidacloprid 3–5 days on tomato; check CIB&RC approved list.

Diseases under cover: powdery mildew, downy mildew, early blight, Fusarium wilt, damping-off in nursery.

Sanitation: remove and destroy infected plants; disinfect tools and footwear; use raised beds and clean planting material.

Soil solarisation: transparent film 25–50 micron for 4–6 weeks in summer reduces soil-borne pathogens and nematodes.

Tomato: indeterminate hybrids, 2.5–3.5 plants/m2, single-stem training, 20–25 trusses per plant; yield 15–25 kg/m2 in polyhouse.

Cucumber: parthenocarpic hybrids, 1.5–2 plants/m2, vertical training; yield 12–20 kg/m2.

Capsicum (coloured bell pepper): 3–4 plants/m2, two-stem training; yield 8–12 kg/m2.

Strawberry: 8–10 plants/m2 in vertical or raised beds; requires cool 15–25°C, suited to Mahabaleshwar/Panchgani.

Gerbera and rose: cut-flower crops in polyhouse; gerbera 6–8 plants/m2, rose 6–8 plants/m2; yield 200–300 stems/m2/year.

Nursery raising: plug trays with cocopeat, 25–30 days for tomato; seedlings ready at 4–5 true leaves.

Pollination: bumblebees at 1 hive per 1,000 m2 for tomato; avoid insecticide spray during bee activity.

Crop rotation and grafting: graft tomato on resistant rootstock against Fusarium and bacterial wilt; rotate with non-solanaceous crops.

Sensors: temperature-RH sensor in a radiation shield at canopy height; PAR sensor; CO2 sensor; soil moisture probes.

Controller: climate computer with setpoints for vents, fans, foggers, screen and heating; log data at 5–15 minute intervals.

Fertigation unit: venturi injector (cheap, EC fluctuation) or dosing pump (precise, EC/pH feedback).

Maintenance schedule: check drippers monthly, filters weekly, replace UV lamps annually, calibrate EC/pH meters monthly.

Backup power: DG set sized to run fans and pumps; power failure in summer can kill a crop within 1–2 hours.

Structural inspection: after each monsoon, check for rust, loose clamps and film tears; retighten bolts and replace damaged pipes.

Automation ROI: climate control and fertigation automation typically raise yield 10–20% and reduce labour 20–30%.

Record keeping: daily log of temperature, RH, irrigation volume, EC/pH, sprays and harvest; essential for traceability and certification.

Harvest at correct maturity: tomato at breaker to pink stage for distant markets; capsicum at full colour; cucumber at 15–20 cm.

Pre-cooling: forced-air or room cooling to 10–12°C for tomato, 7–10°C for capsicum; removes field heat within 2–4 hours.

Cold storage: tomato 10–13°C, capsicum 7–10°C, cucumber 10–12°C; RH 90–95%; avoid chilling injury below 7°C for capsicum.

Grading: size grades (A/B/C), colour uniformity, freedom from blemishes; pack in CFB boxes of 5–10 kg with ventilation holes.

Packaging: corrugated fibre board with 2–5% ventilation area; cushioning with paper or foam for capsicum.

Transport: refrigerated vans at 10–12°C; open trucks cause 10–20% post-harvest loss in summer.

Marketing channels: direct retail, e-commerce, APMC mandi, exporters; FPO aggregation improves bargaining power.

Traceability: label with farm ID, harvest date and grade; required for export and organised retail.

Value addition: sorting, washing, waxing and consumer packs raise realisation by 15–30%.

Pesticide handling: wear gloves, mask, goggles and full-sleeve clothing; never spray against the wind; observe re-entry interval (typically 24 h).

Sprayer calibration and maintenance: check nozzles, pressure and flow before each spray; keep a stock of spare nozzles.

Electrical safety: use MCB/RCCB, earth the structure, keep cables off the floor; water and electricity together are high-risk.

Structural safety: do not walk on film roofs; use ladders and harnesses for height work above 2 m.

Heat stress: in summer, work in early morning and evening; provide drinking water and shade; monitor for heat exhaustion.

Chemical storage: locked, ventilated store away from produce; keep Material Safety Data Sheets (MSDS) accessible.

First aid: eyewash station and first-aid kit near the greenhouse; train at least one worker in first aid.

Waste disposal: empty pesticide containers triple-rinsed and punctured; never reuse for food or water.

NHM/MIDH: subsidy up to 50% for polyhouse (as per norms) and 50% for shade net, with cost norms revised periodically.

Maharashtra state schemes: 50% capital subsidy on polyhouse and irrigation; check the latest GR and district horticulture office.

PMKSY (Per Drop More Crop): 45–55% subsidy on drip and sprinkler systems.

NABARD and bank finance: term loans for protected cultivation; KCC for working capital; interest subvention schemes apply.

PMFME: 35% subsidy up to Rs 10 lakh for food processing and value addition units.

Agriculture Infrastructure Fund (AIF): 3% interest subvention and credit guarantee for post-harvest infrastructure.

Project report: include cost of structure, irrigation, planting material, working capital, yield assumptions and break-even.

FPO formation: 10+ farmers; enables collective marketing, input purchase and access to larger subsidies.

Insurance: PMFBY covers notified crops; check whether protected cultivation is covered in your district notification.