Grand Erie Master Gardeners

Native Seed Sowing Guide for Ontario

Each species of native plant can have specific environmental requirements in order for their

seed to germinate.

An excellent resource for information on the germination needs of a particular native seed is

Prairie Moon Nursery’s website at https://www.prairiemoon.com

Click on the particular plant seed you are researching, then under DETAILS, click on the

information beside the Germination Code. This will tell you whether the seed requires cold

moist stratification, the number of days of stratification required, and other important details like

whether the seed needs light to germinate.

Cold Moist Stratification

In nature, a dormant period during the winter protects seeds from germinating as soon as they

fall to the ground. If they were to germinate in September, the seedlings would not be big

enough to make it through the winter. Therefore some seeds need to be exposed to a minimum

length of cold and wet weather before they will germinate when temperatures increase (similar

to a winter outdoors).

Check online to see if the seed variety you wish to sow requires cold moist stratification.

If it does, you can achieve this in several ways:

Direct sowing:

This involves sowing your seed directly into the soil outside in fall or winter. This means they

will be cold moist stratified naturally by the winter weather in Ontario. A large percentage of the

seed may be lost to birds/animals/insects using it for food, some seed being “washed away” by

rain and snow, and if the area is not well marked you may not recognize the tiny seedlings when

they emerge and run to the risk of weeding them out by mistake.

Winter Sowing:

This technique can be used for any seeds that are not tropical (not just for seeds that require

cold moist stratification). Winter sowing involves surface sowing the seeds in January or

February in well-draining pots or containers that hold at least 10 cm of moistened potting soil,

and protecting the surface of the pots/containers from rodents by covering them with a dome

that allows snow and rain to enter freely. Using empty plastic bottles cut in half horizontally with

drainage holes made in the bottom and the lid left off to allow entry of snow/rain is one common

way to winter sow. In the spring when the seedlings have two sets of true leaves, they can be

planted out into your flower beds.

Using the refrigerator:

If you need to cold stratify your seeds but it is already March or later and warmer weather is

coming, you can break their dormancy using your fridge. Mix the seeds with an equal amount

or more of MOIST fine sand, vermiculite or other sterile medium. Place the seeds in a labelled

plastic bag and store in the refrigerator. Check weekly for germination or molding - if either

occurs then plant as soon as possible.

The number of days of cold moist stratification required, whether in the refrigerator or directly

outside, varies depending on the species.

https://greenup.on.ca/growing-native-plants-from-seed-in-the-winter/Other

Other:

Not all native seeds require cold moist stratification to germinate and some can be sown directly

into the ground or in pots at any time of year.

Other seeds have more intensive germination requirements. For example, large-flowered

trilliums have seeds that must be planted fresh or kept moist, and they require double dormancy

over two years before they will germinate.

Some seeds require light to germinate and must be surface sown, while some seeds with tough

coatings require scarification.

It is therefore important to research the germination needs of individual species of seeds before sowing.