Updated: Feb 7, 2022
Scarification & stratification are not complicated. So don't let the terms scare you away from winter sowing!
Many gardeners like to get an early start and have their seedlings ready to plunk in the ground as soon as the temperature breaks 50. If you are thinking of starting some native perennials, the germination rate of many native seeds can be improved greatly if you check their germination requirements carefully.
Scarification is a process of scarring the seed coat, before you plant. Many seeds with thick or wrinkly coats benefit from scarification, This scarification process helps to get water through the seed coat and get germination started more efficiently.
Samples include Sweet peas, Lupine or Sunflower seeds.
The simplest way to scarify a seed? Grab a piece of sandpaper or a file and give the seed coat a little brush or nick. Be prepared to plant scarified seeds right away (spring) or start in a jug (late winter), as they will be ready to take up water once treated. Pay careful attention to the needs of each seed type as this will determine when and how to start the whole process in preparation for spring planting.
Stratification involves taking your collected seeds and treating with cold and moisture prior to planting/starting them (think seeds overwintering outside under the snow). You can accomplish this by placing your collected seeds on a damp coffee filter, placing the filter in a sealable waterproof container with a little extra water, and storing it in the fridge for 30 days.
Samples of native seeds that may benefit from stratification to optimize germination are Baptisia, Cardinal flower, Joe Pye Weed and Golden Alexander.
The number of days of cold treatment can vary so check suggested timeframes (see links below). This will help you know when to start the process.
Our recommendations on websites for stratification and scarification information:
Our recommendations for sites to find out which seeds benefit from which treatment::
Our recommendations for YouTube how-to's on winter sowing: