Som is a perennial with a four-year gestation from seedling. Everything below — site, spacing, nursery protocol, nutrition and canopy management — is set once and lived with for decades, so the establishment decisions carry more weight than any single season’s operation.
Establishment
| Parameter | Recommendation |
|---|---|
| Site and land preparation | Elevated, well drained, humus-rich; plough or deep-dig to 30 cm; grade slopes and raise bunds; cattle-proof trench before planting |
| Soil pH | 5.2 – 6.5 |
| Planting season | Pre-monsoon (April – June) and post-monsoon (September) |
| Spacing and population | 3 m × 3 m — 444–450 per acre, 1,111 per hectare |
| Pit | 45 cm depth × 30 cm breadth (one cubic foot) |
| Planting material | Seedlings or saplings 9–12 months old; supply 10 % extra against transit and mortality loss |
| Gestation | 4 years from seedling; 2–3 years from sapling |
| Leaf yield at maturity | 18 – 20 MT / ha / year |
| Propagation | Sexual (seed) and vegetative — hardwood stem cutting, single leaf-bud cutting, air layering |
Nursery protocol for som
| Step | Specification |
|---|---|
| Seed collection | May – June; select seed of at least 0.3 g weight and 0.7 mm diameter |
| Cleaning and testing | Wash off pulp under running water; float-test for viability; shade dry |
| Treatment | Dress with 0.2 % Ceresan; soak in water for one day before sowing |
| Nursery bed | 5 m × 1.5 m raised 15–20 cm; soil mixed with 0.5 cft FYM; about 2 kg seed per bed; 5 cft FYM and thatch mulch |
| Polytube alternative | 15 × 20 cm tubes filled with sand : soil : FYM at 1 : 1 : 1; transplant seedlings at 2–3 months |
| Germination | 45 – 60 days |
| Clipping | At 30 cm height, pinch out the apical tip with 3–4 leaves; spray 0.03 % Dimecron |
| Seed viability in storage | Sow within 10–20 days of harvest; viability nil by about 45 days; store at 10 °C |
Som seed will not wait. Viability falls to nil in about 45 days, so seed
collection, cleaning and sowing have to be planned as one continuous operation in
May–June, not as separate tasks.
Nutrition and canopy
| Operation | Young (1 – 2 yr) | Mature (4th yr onward) |
|---|---|---|
| Farmyard manure | 0.5 cft / pit | 1 cft / pit |
| NPK | 50 : 25 : 25 kg / ha / yr | 100 : 50 : 50 kg / ha / yr |
| Season and method | Feb–Mar and Aug–Sep, ring method | Feb–Mar and Aug–Sep, ring method |
| Pollarding | Not applicable | From 5–6 years, above 1.5 m, in Jun–Jul or Oct–Nov |
Intercropping and weeding
- Gestation years: cabbage, knol-khol, cauliflower, onion, French bean and potato; soybean, green gram and black gram add nitrogen as well as income.
- After year three: turmeric, ginger, colocasia and chilli perform under the closing canopy.
- Weeding: hand-pull before flowering and loosen soil for percolation and root aeration; spot-treat thatch grass, keeping herbicide off the host plants.
Intercropping is not a side activity during the four gestation years — it is what
makes the wait survivable. Shade-loving intercrops generate 47–85 % additional income
over sole cropping without affecting host plant growth or leaf yield.