1. Practices to enhance germination
seed sizing (larger seeds have shown greater viability and vigor)
seed priming
pregerminated seeds

2. Principles of seed priming
use of osmotic or matric forces to hold seeds in the lag stage before redrying
controls seed hydration to permit pregermination metabolism but prevent radicle emergence
results in more uniform germination in a shorter time span

3. Seed priming - two methods
osmotic seed priming
seeds are placed in an aerated soln of PEG for 1-15 days
seeds are dried (to near original weight)
matrix seed priming
PEG soln is replaced with a solid matrix (e.g., vermiculite)
“matrix force” is created by limiting moisture
used commercially for lettuce and pansy to overcome thermodormancy

4. Pregermination
germinated seeds are dispersed in a gel (fluid drilling) or dried before use
advantages: fast, uniform germination at or near 100%
disadvantages: increased cost, seeds with a shorter shelf life