Seed Stratification - Fall Planting
By Ashleigh Smith
Published 5 Nov, 2021
Updated 15 Aug, 2023
Stratification is the process of mimicking seasonal climate conditions to trigger germination in seeds. These may include changing temperatures, humidity, or light cycles. Seeds such as native plants, wildflowers, and perennial flowers rely on cold to warm changing weather to start the germination process. Their freshly dropped seeds remain dormant until experiencing the cold of winter followed by increased humidity with warming spring temperatures. This is how large flower fields and meadows are developed throughout the prairies and mountains.
Plant Cold Stratifying Flowers Now
You can take advantage of this process by planting in the fall for good germination and early flowering in the spring. Wildflowers and perennial seeds will follow the natural cycles of your climate by remaining dormant until the germination conditions are met.
If you are new to using these practices, try our Fall Planting Perennials - 5 Classic Flowers assortment. Simply plant them in the fall or early winter. They will germinate in the spring to provide beautiful blooms from mid-spring to fall. Fill a flower bed, create a border, or use in containers for a bright spot all season long!
Fall Planting Perennials - 5 Classic Flowers
Flowers Include:
Wildflowers To Plant in the Fall
Planting wildflowers now will also help suppress weed growth throughout the spring months. Simply broadcast your seeds and walk away. If you are planting in an especially dry area, your seeds will likely benefit from additional water until they become established. Make a selection from one of these special wildflower mixes to get started, or stock up on stalking stuffers for the gardener in your life. We are also continuing to donate 10% of Save The Monarchs Seed Collection purchases to the Monarch Joint Venture organization and a portion of Save the Bees wildflower mixes to The Bee Conservancy.
Save The Bees
Hummingbird & Butterfly
All Perennial Flower Seed Mix
Save The Monarchs
Types of Stratification for Spring Planting
If you find yourself wanting to grow these types of plants in the spring, try one of the following methods to improve germination. For native plants, wildflowers, and some other perennials, try cold stratification. Heat Stratification should be used on seeds that sprout at the end of the summer. Scarification is a process that can be used on seeds with abnormally hard coats. And inoculation is used on plants of the legume family to encourage nitrogen transfer by root nodules.
Cold Stratification
- Dry - Dry stratification is done by keeping your seeds in a fridge or freezer for about a month. This simulates the needed cold temperatures during the dormant winter season. When you plant your seed in a warmer outside environment, the seed is signaled to “wake up” and sprout. This method is popularly used for strawberry seeds.
- Water and Paper Towel:
- Step 1: Soak your seeds for 1-2 hours.
- Step 2: Drain the seeds using a paper towel. After draining, spread the seeds out over the wet paper towel.
- Step 3: Wrap a dry paper towel around the wet one to prevent molding issues during the stratification process.
- Step 4: Seal the paper towels into a baggie and label with the varieties and date.
- Step 5: Refrigerate for 2-4 weeks. Plant any early seed sprouts as they are observed.
- Sand and Water: Try this method to more easily spread small wildflower seeds when planting.
- Step 1: Add about 1/4 cup of sand to a mixing container.
- Step 2: Add water to the sand until you can form a ball in your hand.
- Step 3: Add your desired seed amount and mix.
- Step 4: Place your mix into a sealable baggie. Label with the variety and date.
- Step 5: Refrigerate for 2-4 weeks Remove and plant any early sprouts.
- Peat Moss and Water: Follow the steps listed for the Sand and Water method mentioned above. Substitute peat moss for the sand.
- Potted Seeds: If starting in 4-inch pots, plant your seeds and place your flat of pots in a protected area. Here in the Salt Lake Area (Zone 7), we have had great success storing the prepared flats under a deck, or other protected location, on the North side of a home. This prevents the wind, snow, or extreme fluctuations in temperature from damaging the pots before you are ready to check on them. About the time you are turning your sprinklers on for the season, you can set your flat out for some water until you are ready to plant. At this stage, be sure to check on your starts to make sure they are getting enough water. Plant when the ground is workable.
Heat Stratification
For plants that usually germinate during the summer with warm temperatures, increase germination by soaking the seeds in hot water. First bring a pot of water to a boil. Remove from heat and add your seeds. Allow the seeds to soak until the water has completely cooled. Plant your seeds per their growing instructions.
Scarification
Scarification is the process of scuffing a hard seed coat in order for water to penetrate it more easily. A seed needs to absorb water to germinate. Scuffing its coat creates small openings for the water to enter, thus increasing the number of seeds likely to germinate outside its natural conditions. To do this, take a sandpaper block and lightly brush your seeds. Outside of seeds with a naturally hard coat, you may see this done to expensive or valuable seeds such as giant pumpkins.
Inoculation
Inoculant is a rhizobia bacteria powder applied to legume plants such as peas, beans, clover, soybeans, and vetch. Only a small amount should be mixed with your seeds to achieve its purpose. These plants naturally “fix” or transfer nitrogen from the air to the soil via their root nodules. This inoculation just gives them a helping hand in poor soil conditions.