Where treatments are necessary to break seed dormancy or to improve germination in nondormant species, simplicity and efficacy are the key to choosing a technique. Commonly used techniques are as follows.
Winter chilling in situ
This is the most straightforward and, in many cases, most effective technique for deeply or lightly dormant seed. Seed is sown in autumn through to early winter and allowed to chill in the soil. Rain increases leaching of germination-inhibiting compounds from the seed coat. Deeply dormant species, such as Astrantia, need to be sown in the autumn to ensure sufficient chilling is experienced. The disadvantage of this technique is that small seeds, in particular, may be lost by being buried too deeply by worm casts, removed by seed predators or washed into deep fissures in the soils by heavy rain.