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Special Seed Germination Requirements

From our January 2022 newsletter.

Some flowers are notoriously easy to start from seed (marigolds, cosmos, amaranth, grasses, zinnias, etc).  Other flowers can make you feel like you haven’t a clue as to what you are doing; for me this was phlox, delphiniums, and foxglove my first year- all of which I’m trying again this season.

Every flower has a different, ideal environment required for them to germinate from seed.  Most seeds packages or websites will include basic sowing information.  Such as:

light required, do not cover

darkness required, cover

72F required to germinate (use a heat mat)

cooler temps required, no heat mat

Most importantly, keep the soil moist but not wet and never allow it to dry out!

And there can be extra steps to get stubborn seeds to germinate, like perennials. I’m talking about cold stratification, seed scarification, and the Speed Dial Method of cold moist stratification. 

Cold stratification is the process whereby seed dormancy is broken in order to promote this germination. In order for the stratification of seeds to be successful, it is necessary to mimic the exact conditions that they require when breaking dormancy in nature.  Cold treatment for seeds is necessary for flowers that require time in the ground over winter in order to germinate.

For the most part, this involves storing those seeds either in the fridge or freezer for 1-2 weeks before you will be sowing the seeds.  (Delphiniums, larkspur, ammi, etc)

Scarification in botany involves weakening, opening, or otherwise altering the coat of a seed to encourage germination. The seeds of many plant species are often impervious to water and gases, thus preventing or delaying germination.  You can nick seeds with the edge of a nail clipper, a nail file, or a knife, or you can sand through the seed coat with a bit of sandpaper; I do this to lupins.

The Speed Dial Method of cold stratification involves placing seeds in a plastic bag with moist growing medium, and placing it in the freezer for a day, then moving the bag to the fridge for a day, and repeating this cycle for 7 days.  The Speed Dial Method was developed by Miriam Goldberger of Wildflower Farm in Ontario.

I’ve included a link where she talks more about this method.

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