If the radicles are longer than 4 mm, they can be damaged during planting. This method is not recommended in areas with cool soil tempertures, as food reserves in the seed are depleted faster in cool soils and may delay emergence considerably. The seed begins the germination process while it is soaking in the priming solution. Priming is stopped just prior to radicle emergence from the seed coat. The seed is then dried down to its original moisture content and planted as a dry seed.
Primed seed germinates faster and more uniformly than non-primed seed, especially in cool soils.
Seeds should be stored under optimum conditions, or the effectiveness of seed priming can be reversed. Chile seed has been treated successfully in laboratory tests and on a limited basis in the field. Some seed companies will sell primed seed if orders are placed far enough in advance for them to treat the seed. One disadvantage of seed priming is variation of soil temperature makes results unpredictable from one year to the next. Seed priming is becoming more popular in the transplant industry, where uniform germination in the greenhouse is critical.