Although they might seem like the same thing, when we are talking about seed viability and germination, we are referring to two different things. Viability means whether or not a seed is alive, while germination refers to whether or not a seed can germinate. The number of seeds viable in a collection doesn’t necessarily equal the number of seeds that can germinate, the difference being that some seeds are immature, or dormant (‘asleep’).
Whenever we make seed collections we try to ensure that seeds are viable and mature (ripe). This is very important because if seeds are not viable, they will not germinate anyhow, and if they are immature they will not survive as well in storage as they would if they were mature. Sometimes we can help seeds to mature after collection by the way they are stored. Also, the way seeds are handled during collection and transport will influence the proportion of seeds that remain viable.
When it comes to testing seed viability, there are a number of different techniques that can be used, some of which actually result in the death of the seed! This means we have to choose a test carefully and ensure there are plenty of seeds left for other tests and storage. As such, viability is assessed on a portion of seeds (perhaps 20 seeds for small collections, 100 seeds for large collections), and this is taken to represent the viability of the entire collection.