Germinating certain native plants can be difficult or yield poor results if not done correctly, check out our printable info pages below for more information.
Starting Native Plants From Seed
Propagating native plants can seem intimidating at first, but with the proper information and germination requirements met, seeds will have a high yield of growth. Lets get into some of the science and seed sowing tips below, followed by some common seed treatments required before planting.
The Science of Seed Germination:
The seeds of native plant species each have their own timetable for germination. A built in physical and chemical dormancy protects them from germinating until conditions are favourable for the seedlings survival, usually in spring. Some seeds have a hard outer coat or waxy layer that keeps water out of the seed. This physical dormancy is overcome in nature in several ways, which include; abrasion from soil, freezing and thawing, digestion by soil microorganisms, passing through the digestive system of animals and fire. A chemical dormancy is broken when the seed is subjected to one or more of the following, changing its physiological structure; spending a period of time in cold, spending a period of time in cold and moist, being in the presence of light for a period of time and being in the absence of light for a period of time.
Most Ontario native plants that have chemical dormancy will lose their dormancy in nature by spending the winter in the ground cold and moist.
Seed Sowing Tips
Until you are ready to plant or apply pre-sowing treatment, seeds should be stored in a cool, dry place and protected against rodents.
Sow seeds shallowly. Surface sow or sow no deeper than the width of the seed and keep the soil moist but not too wet.
If seeds are very small, you may choose to use a spray bottle to ensure the seeds don't get displaced by large water droplets.
Clearly label and date the seeds when applying the pre-treatment method.
The germination time of seeds varies, it can take a few days up to a few weeks. Be patient if the seeds don't germinate right away.
The average frost free date for South Georgian Bay is May 11th.
For indoor germination: seeds may take a few weeks to germinate and require some maturation before the seedlings can be planted outside. Plan for around 2 months of growing time (germination and maturation), plus add the required pre-treatment time if seeds need stratification.
For outdoor germination: seeds will germinate when the weather and time is right.
Types of Seed Treatments
It’s possible to replicate a natural cycle that cause dormant seeds to germinate by pre-treating the seeds before you plant them. Below are some common pre-treatment methods, the germination codes denoted by a letter are often found on your seed envelopes. You may need to use one or more to get a particular species to germinate.
(A) NO PRE-TREATMENT NECESSARY other than cold, dry storage (also called cold-dry stratification).
(B) SEEDS NEED SCARIFICATION: rub between sand paper to remove some of the seed coat
(C) STRATIFICATION NEEDED: seeds germinated after pre-treatment of cold-moist stratification. Approximate number of days is in parentheses (i.e. C(30) = 30 days of cold, moist conditions needed) *see Germination Code C stratification recommendations below
(D) SURFACE SOW: seeds are very small and need light to germinate
(E) DOUBLE DORMANCY: Seeds need a warm, moist period followed by a cold, moist period: Mix seeds with sterile medium, place mixture in a sealed plastic bag and store in warm (26°C) place for 60– 90 days. Then place in refrigerator (1-3°C) for 60–90 days before sowing. Or, sow outdoors in early spring and allow one full year for germination.
(F) BEST PLANTED OUTDOORS IN FALL: sow seeds in prepared garden beds or labeled pots in November/December
GERMINATION CODE C : Cold moist Pre-treatment
For both methods: Check once a week to ensure the seed hasn't completely dried out. If premature sprouting occurs, plant immediately
PAPER TOWEL OR COFFEE FILTER METHOD:
Suited for containers or flats
Wet a paper towel or coffee filter and allow excess water to drain off. Arrange seeds in a single layer on 1/2 the surface, then fold the paper in into a quarter. Place the folded paper in a labeled resealable bag or container and put in the refrigerator for the recommended time.
Suited for outdoor garden bed or pots/flats
Place seeds and sand in a bowl, add 1 to 2 tsp of water, or enough water to form sand into a ball. Mix together. Place this in a labeled container or resealable bag and refrigerate for the recommended amount of days.
Starting in pots or flats:
After applying the pre-treatment, place the seeds in a container filled with moist growing medium soil, and lightly cover them to a depth the same size as the seed, or surface sow.
Place the containers under grow lights or in a sunny window.
Ensure the seeds stay moist throughout the germination period
Wait until the seedlings have matured enough, forming a second or third set of leaves before transplanting outside. Do not plant outside before your regions frost free date.
Starting in pots or flats:
Outdoor weather varies, and soil temperatures determine when your seedlings will emerge. Cool-season plants typically germinate in May, while warm-season plants may not sprout until the soil warms in June.
You may use: regular plant pots, large yogurt containers, large bottles cut in half, large milk cartons cut in half, salad containers. Ensure you poke holes at the top and bottom for drainage, and label!
Fill the container with soil (at least 3” deep), and water. Place the seeds on top of the soil and lightly cover or surface sow.
Place the pots or flats on the north side of a building, or out of direct sunlight, and protect the seeds from rodents by placing plexiglass/chicken wire/screen over top, or put containers in a bag or box.
When the snow melts, move the containers to a sunny location, remove the lid fit they have one and keep moist.
Starting in outdoor garden bed:
Prepare the outdoor bed by removing weeds and levelling off the area.
You may place the seeds in a prepared garden bed throughout Fall (November/December), or sow them in early Spring (March) if the pre-treatment is 60 days or less.
If you don't sow outdoors in Fall or early Spring you will need to apply the required pre-treatment for seeds before sowing them in an outdoor garden bed in Spring.
To distinguish your native plants from weeds, plant one species in each spot and make a sketch or label of what you planted there. You may also decide to plant in rows and then transplant seedlings afterwards.
(Garden plan design by Kate Brandes, PDF: https://lgnc.org/pdfdocs/brandes_book.pdf)
* See Germination Guide below