Seed Germination Rate Calculator
Calculate germination rate (%), mean germination time (MGT), germination energy, and coefficient of velocity for a seed batch.
Formulas Used
Germination Rate (GR%)
GR = (Ngerminated / Ntotal) × 100
Germination Energy (GE%)
GE = (Ngerminated in energy period / Ntotal) × 100
Mean Germination Time (MGT) — requires daily counts
MGT = Σ(ni × ti) / Σni
where ni = seeds germinated on day i, ti = day number
Coefficient of Velocity (CV%)
CV = (Σni / Σ(ni × ti)) × 100
Germination Index (GI) — Czabator (1962)
GI = Σ(ni / ti)
Assumptions & References
- Seeds are counted once per day under controlled or field conditions.
- A seed is considered germinated when the radicle (root) emerges visibly (ISTA standard).
- Germination Energy period is typically the first one-third of the total observation period.
- GR ≥ 80% is generally considered excellent; 60–79% acceptable; < 60% poor (ISTA, 2022).
- MGT formula: Labouriau & Valadares (1976); CV formula: Kotowski (1926).
- GI formula: Czabator, F.J. (1962). Forest Science, 8(4), 386–396.
- ISTA (2022). International Rules for Seed Testing. International Seed Testing Association.
- Results assume uniform environmental conditions (temperature, moisture, light) throughout the test.