Seed Rhizome Calculator

Budget your seed like a banker: ginger seed is 40–50% of variable cost (Chapter 05). Enter your spacing and seed-piece size and the calculator returns plants, pieces, kilograms and cost.

Seed grading: five rhizome pieces from too small to cut into piecesFive seed pieces of increasing size, from a single thin-budded sliver through the 20 to 30 gram ideal to an oversized 40 to 50 gram piece, a wilted piece to discard, and a long finger that must be cut down to 20 to 30 gram pieces.Target: 20–30 g per piece, with 2–3 plump budsBelow ~15 g the sprout is weak; above ~50 g you are burying moneycut hereToo small1 thin bud — poor startIdeal seed2–3 plump budsLarge piecefast start, costly seedDiscardwilted, soft or diseasedCut into pieces20–30 g, 2–3 buds eachGrade in the shade on the day you lift: seed keeps far better in pieces than in heaps
Seed grading, left to right. The 20–30 g piece with 2–3 plump buds gives the most uniform stand per tonne of seed bought.

1.00 ha = 2.47 acres

cm

20–25 cm on beds · 50–60 on ridges

cm

20–25 cm between sets

g

Classic target: 20–30 g with 2–3 buds

%

For gap-filling and rejects

/kg

Your local currency

Plants per hectare—
Seed pieces needed—
Seed weight—
Seed cost—

Degree-day emergence predictor (GDD model · base 15 °C)

Seed rate in kilograms per hectare for each planting systemRaised beds 1500 to 2000 kg per hectare, ridges and furrows 1600 to 2000, slope planting 1200 to 1500, high-density green ginger 2000 to 2500.Raised beds (Kerala style)1,500–2,000 kg/haRidges & furrows1,600–2,000 kg/haSlope / patch planting1,200–1,500 kg/haHigh-density green ginger2,000–2,500 kg/ha05001,0001,5002,0002,500
Data table
Seed rate by planting system
Planting systemSeed rate
Raised beds (Kerala style)1,500–2,000 kg/ha
Ridges & furrows1,600–2,000 kg/ha
Slope / patch planting1,200–1,500 kg/ha
High-density green ginger2,000–2,500 kg/ha
Seed rate by planting system. At 20–30 g per piece these rates are what set the seed bill — usually 40–50% of variable cost.

Ginger sprouts when heat accumulates — roughly 150 °C·days above a 15 °C base. At the ideal 25–30 °C that lands at 10–15 days; in a cool spell it stretches toward 4–6 weeks. Use the average soil temperature at seed depth (4–6 cm) for the weeks after planting.

°C

Daily mean, not the afternoon max; under mulch soil tracks the air mean

Shows the estimated calendar date when sprouts appear

Heat units per day—
Days to first sprouts—
Estimated emergence date—
Emergence band—

Model: 150 °C·days above 15 °C — a planning estimate. Soil texture, mulch type, seed-piece size and pre-sprouting all move reality by a few days either way.