Germination Energy: The Interim Count on Day Three
A seven-day germination test is read twice, and the first reading has a name of its own. Germination energy is the share of seeds that have produced a well-developed seedling by day three. It describes how briskly a lot gets going. Mistake it for the final result and a slow lot looks like a bad one.
What counts on day three
Only seedlings whose essential structures are fully formed at that point are counted. A seed with the root tip just breaking through does not enter this figure.
The threshold is therefore stricter than at the closing count, and that is its purpose: it separates the vanguard from those still starting up. On day seven everything that has become a normal seedling is counted, along with the abnormal seedlings and the seeds that did not germinate.
What the figure stands for
Germination energy is treated as a first indication of a lot’s viability and of how it will behave in the field. The reasoning is plain enough: in soil a seedling competes with drought, capping and weeds, and every day of head start counts there.
It remains a figure about speed, though. Two lots with identical germination capacity can have widely different germination energies, and a lot that starts late and comes up in full will look poor on day three and sound on day seven.
How it relates to vigour
Both terms aim at quality beyond bare yield, but they measure different things. Germination energy measures speed under good conditions. Seed vigour measures what survives poor ones and needs its own stress treatment to do so. A more finely graded speed figure is the speed of germination index, counted daily from day two through day seven.