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Growing Native Plants
from Seed

It is surprisingly easy and cheap to grow your own native pollinator garden from seed, though there are a few things you need to know.

To learn about seed collection, check here.

A lot of native plants need to go through a period of cold weather to be able to germinate in spring.

Therefore some seeds need to be stratified. But the good news is if you are too late or in an environment, e.g. a school where stratification is too inconvenient, many species will germinate without stratification.

There are different ways to stratify seeds:

Let winter do it naturally through outdoor cold-moist-stratification

or mimic conditions in your fridge.

Check out the advantages of 4 different methods and the exact steps to successfully grow native plants from seed.

(Note: There are as many different methods as there are people on the planet :-)

Which of these Methods Work For You?

1. The Natural Method:
Sow in Fall and Winter
2. "Wintersowing"
Mini-Greenhouse-Method

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3. Sow in Spring after
Cold-Moist-Stratification
4. Grow Indoors
on a Window Sill
Advantages and Disadvantages
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We highly recommend this method as the default method and only complement it
with other methods for specific needs

Seeds are sown outdoors between November and February and stratify naturally

+ This process grows native plants close to how nature does it. Humans are just scratching the surface of comprehending how interconnected all natural processes are. Long-term success for plants grown in this way should be the greatest.

+ New research found that the longer the stratification period for the seeds is, the greater the genetic diversity in the seedlings, which dramatically enhances biodiversity and readiness for climate change

+ Straightforward and timely process, collect the seeds, sow them and forget about them until the end of March

+ No need for Ziploc plastic bags

+ Takes no space in the fridge

 

- Unwanted seeds are still plentiful in the fall and can fly into pots

- Small-holed mesh is required to keep mice and birds from eating the seeds

- Since spring is far away, it is paramount that every pot has a label written with a very durable pen or pencil, especially because the pots will need to be moved from the shade to part sun.

Great for school projects, vegetables, moisture-loving plants and tiny seeds

Seeds are sown between the 21st of December and February and stratify throughout winter

+ Continuously moist environment through condensation and recycling of the water benefits moisture-loving plants that are otherwise finicky to get to the seedling stage
+ Great for tiny seeds that need light to germinate since they can be safely surface-sown and stratify naturally. When you stratify tiny seeds in the fridge, mixing them into some soil is often recommended. This prevents some seeds from germinating if they require light for germination. If they are winter-sown, all seeds can be surface sowed, which increases the germination rate.

+ No extra protection against mice, squirrels, and birds eating the seeds is needed

+ Great for school seed-sowing projects

+ Almost no unwanted seeds will get into the pots; great control over what you grow

+ No bags with seeds for stratification in the fridge

+ Only sporadic checks on the seeds/seedlings are necessary until March

+ Plants germinate earlier in spring and develop quicker. This is a real advantage for annuals and vegetables, but the consequences on longterm-health for native plants is not studied

- Plastic containers with the matching lid need to be collected

- Time-consuming to put set-up together

- Might promote pathogens on usually hardy plants through the consistent presence of moisture

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Feels so good to get out in the garden
Sow recently obtained seeds
Grow more, more, more-
and grow the seeds you forgot

Seeds are sown between March and May and stratification needs to be mimicked in the fridge

- Seeds need to be stratified in plastic bags in the fridge
- The process requires some planning since different species require different periods of stratification
- But even nurseries and government institutions can't agree on the needed time to finish stratification. If seeds start germinating in the fridge after they break dormancy, it becomes challenging to sow them.
- Protection against squirrels is needed


+ Hardly any seeds are still flying around, so almost all seedlings will be the sown ones which makes it a very successful process 
+ It feels so good to get gardening when warmer days become pleasant
+ Plants germinate very soon after sowing, which makes it a continuous process 
+ Gardening in spring fits within Western gardening traditions, therefore, it feels right, and it makes it easier to get people excited to get sowing
+ Seeds obtained in spring can still be sown

Great for schools
Observe the seedlings grow right in the classroom

Seeds are sown between March and May and stratified in the fridge

- This is quite an unnatural process, and hardening off might be needed

- Seeds need to be stratified in plastic bags in the fridge
- The process requires some planning since different species require different periods of stratification


+ No protection against squirrels is needed
+ No outside seeds, complete control over what can grow
+ Plants germinate very soon after sowing and grow very fast

+ Since the seedlings grow indoors, it can be easily observed 

+ and makes it a great project for schools

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1. HOW TO SOW IN FALL/WINTER

THE VERY EASY WAY
Seeds will stratify naturally going through the winter outdoors

How to Grow Perennials from Seed: Fall
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From November until the beginning of February

Fill containers with well-moistened potting soil.

Sow the seeds on top and gently press them to have contact with the soil. If the seeds need light to germinate, don't add soil on top. Otherwise, sprinkle with a bit of soil or coarse sand.

Label each pot with the name and the source of the plant. Adding the source information enables you to support genetic diversity in a planting. Add all other information that could be important for you.

Put the pots in a shaded location that will receive rain and snow and is far from stems with seed heads to avoid those seeds falling into the pots.

After Sowing

To give extra protection, cover the pots with a layer of leaves.

Protect from squirrels, birds, and mice by covering the pots with a fine mesh and tucking it under the pots.

If you don't protect the seeds, none will likely be left by spring unless you grow them on a balcony.

You will not have to look after your seeds until the weather gets warmer.

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March to May

When the days get warmer, remove the leaves and move the pots into a part-sunny location. 

The seeds will germinate at very different rates depending on their species. From that point onwards, the seedlings can never dry out.

Seedlings are ready to be planted in the soil in summer or fall. 

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How to Up-Pot

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The seedlings start to outgrow their container
in May or June. They will not grow any further.

Very carefully divide them into chunks not to damage the roots too much.

Put them as a clump in the middle of a 10 cm or bigger pot in fresh potting soil.

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The seedlings start to outgrow their container in May.

Very carefully divide them into chunks not to damage the roots too much.

Put them as a clump in the middle of a 10 cm or bigger pot with fresh potting soil.

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The seedlings have reached maximum growth in this container and will no longer grow if not up-potted.
This is a mixed pot with giant yellow hyssop, purple coneflower, blazing star and asters. It got up-potted into 8 small pots. 

After up-potting, all seedlings have enough space to start their next growth spurt. The timing of up potting greatly determines how well the seedlings can grow and how quickly they will be ready to be planted into the landscape.

After up-potting, water the seedlings well. It is a good idea to keep them in a bucket where they can soak up water for some hours. Then keep them in full shade for a few days until they have recovered. When they look happy again, you can put them back into a part-sun location.

Ready to Be Planted

Most Plants Will Be Ready To Be Planted By Mid-Summer

It is essential to match the plant to the right conditions of a location so that the plant can thrive. 

Even drought-tolerant plants need frequent watering until their root system is well established.

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How to Grow Perennials from Seed: Services

More Details on

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2. HOW TO WINTERSOW

THE VERY CONTROLLED WAY
Seeds will naturally stratify outdoors

Winter sowing is a fun method that uses mini-greenhouses to speed up the growing process of the plants. The plants will be abundant, lush, and ready to be transplanted in summer.

You can find a detailed video by Dolly Foster, a Master Gardener, on Wintersowing.

Or check out our step-by-step guide. 

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From December 21st to the Beginning of February

Sow seeds onto moist soil in a deep container to support vigorous root growth.

 

Label inside and outside with a very durable garden marker or a pencil.

 

Water so that soil is well moistened but not wet. Best to add some snow on top.

Tape the lid onto the matching bottom.

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During Winter

Keep containers in a shaded spot or one that doesn't receive midday sun so that the sun doesn't heat the little greenhouse up to extreme temperatures.

That's all you need to do until temperatures warm up.

It is very unlikely that the soil dries out, you can check if you are worried.

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Starting in March

Put containers into a partly sunny place. On warmer days, open the lid and only close it at night.

Once the last danger of frost has passed and day and nighttime temperatures get warmer, remove the lid altogether.

Seedlings will soon have to be up-potted and transplanted into the gardens.

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3. HOW TO SOW IN SPRING

THE CONTROLLED WAY
Seeds must have been stratified either in the fridge or just been collected from the plant before sowing

Stratify
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STRATIFY SEEDS FOR
SPRING SOWING

The following explains the basics of the cold-moist-stratification method in the fridge. It will work for a lot of popular pollinator plants with seeds that require a cold and moist period to break dormancy. To propagate woodland plants, shrubs and plants that need a different stratification, consult wildplantsfromseed.com  or for even more detailed information, check out the instructions from  USDA.

Storage

From Harvest until Cold Moist Stratification

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Keep the seeds in paper envelopes labelled with the plant name, location, and date of harvest until you start the stratification process. This is around mid-February for most plants.

For the exact length of the required stratification time and method, check out the website of Prairie Moon Nursery.

To figure out when to start the stratification process, count back the days of cold moist stratification from the day you want to plant. Native plant seeds are used to the cold and, therefore, can be sown anytime, irrespective of the last frost date, as long as they haven't germinated yet.

Stratification

Usually, in February and March

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To stratify the seeds, transfer them onto a moist paper towel.

Fold the paper towel in half or quarters and put it into a Ziploc bag.

Close the bag tightly.

Label with name, location, and start date of stratification. For ease of use, you can add the needed CMS days or the date when seeds are ready to be planted.

It also helps to add the planting dates to a calendar.

Keep the bag in the fridge until you sow the seeds outside.

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Sowing

From March until May

Fill containers with very well-pre-moistened potting soil.

Sow the stratified seeds on top and gently press them onto the soil to have contact with the soil. Sprinkle some soil or coarse sand on top if the seeds don't require light to germinate.

 

Water well.

 

Label each pot with the name and the source of the plant if you know it to be able to support genetic diversity in a planting.

Put in a part sun location and ensure the soil never dries out.

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After Sowing

Protect from squirrels, birds, and mice by covering the pots with a fine mesh and tucking and securing it under the pots.

The seeds will germinate at very different rates depending on their species. Once the seeds have sprouted it is imperative never to let the seedlings dry out.

Most seedlings don't like the stress of a full-sun location and prefer to be located in part sun.

Picture: This box of butterfly weed seedlings already fed 5 monarch caterpillars as small seedlings ;-)

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April to August

By June, most seedlings must be up-potted, divided and planted into bigger pots to allow rapid growth.

Usually, about one month after up-potting, the seedlings are ready to be planted into the soil. This is ideally by mid-summer.  

The seedlings can further be up-potted if needed later in the year and can be planted out until the end of October.

 

They can also be overwintered in their pots in a sheltered place outdoors and planted in spring.

THE DETAILS

Containers & Soil

Any container at least 5 cm /2 inches deep can be used. 
Cut holes into the bottom of the container if it doesn't have drainage holes.
Any potting soil is sufficient, there is no need to buy seed starting mix, but finer potting soil works better. 
Most soil comes rather dry. To save time, you can pour quite some water into the opened bag and let the soil absorb it for some hours. Soil needs to be evenly moist before sowing.
Fill containers and tap them to settle the soil until they are almost full.
Leave about half a centimetre from the top.

Soil
Sowing Your Seeds

Put seeds in the palm of one hand, pick the seeds you will sow, and sprinkle them as evenly as possible onto the soil.

Very gently press them into the soil and add a dusting of soil or coarse sand on top. As a rule of thumb, seeds should get covered with soil about their own thickness. Smaller seeds often need light to germinate and should just be sown on the surface.

Water gently to settle the seeds, or add snow on top.

It is helpful to mark every container with the name of the plant and its origin. This enables you to grow plants of the same species from different sources close together so that a more diverse and resilient gene pool can be created through cross-pollination.

Cut-up yogurt containers work very well to create your own tags.

For detailed instructions on how to sow, check out Heather McCargo's short video.

Protection

It is important to protect the pots so that squirrels can't dig up the soil and destroy the seeds or seedlings or that birds can't eat the seeds.

The easiest is to use sturdy plastic netting.

Chickenwire is a method that works very well - but working with chickenwire is quite unpleasant unless you build a cage that you can use for years.

Covering the soil and seeds with some leaves is a good idea since birds can still pick through the net and eat the seeds, and it also protects the soil as a living system.

It is surprising how effectively simple plastic bags prevent squirrels from digging. Be aware that this method creates a greenhouse that provides a warm and moist environment. Germination will most likely happen earlier than without this protection. If you cover the seeds directly with a plastic bag like a blanket at night to prevent squirrels from digging, you need to take it off during the day. On the other hand, if you build a structure under which the seedlings can grow, you can leave the clear bags on it until the end of May because you created a simple greenhouse. As the evaporating water condenses and drips back into the soil, watering needs are reduced to a minimum. In that case, make sure the pots are in part-sun only and not in the powerful mid-day sun. 

See-through containers with a matching bottom from kitchen recycling can also be made into squirrel-prove greenhouses. 

Most native plants don't need a head start given by a greenhouse. It is an excellent method for annual herbs that support butterflies like fennel and dill.

 

By the end of May, it is best to take the plastic off since the moist environment favours mould growth.

Protection
Care
Caring for Your Seedlings

Seeds germinate at their own pace depending on species, daytime and nighttime temperatures, moisture, and light conditions.

Once the seeds have sprouted and are small seedlings, they must never dry out. From now on, check daily if the soil needs watering.

Once the seedlings have their second set of true leaves (cotyledons are the very first leaves that often don't look like the plant's leaves) and they start to get crowded, it is time to up-pot them. Divide them into roughly square-inch pieces and put them in the middle of a bigger pot just as they are, as one piece. This way, the roots don't get damaged, and the plants have space to move outwards.

Since potting soil has fertilizer added and most native plants, particularly prairie plants, thrive on poor soil, there is no need to add fertilizer at any time.

Some Useful Tips

  • Potting soil consists mainly of peat moss. To avoid the destruction of our ecologically important peatlands, experiment with other growing mediums, like homemade compost and leaf mold.

  • Smaller containers dry out faster, which means that frequent watering becomes essential. Bigger containers, like old window boxes or even big plastic containers of fruits and vegetables, hold more moisture and allow for a bit more ease, and plants grow much quicker and bigger.

  • Almost all species of seedlings grow better in a part shade location and not in full sun. Seedlings in the wild will grow in the protective shade of mature plants.

  • The right timing of up-potting and planting out will greatly determine the success of the plants. Dividing the seedlings and getting them into bigger pots usually can start at the end of June, planting the young plants into the soil around August.

Heather McCargo, the founder of the Wild Seed Project, is an excellent source to learn more about growing native plants from seed. 
She has decades of experience with a wide variety of native plants, methods and soils. The featured talk will carry you off into the wonderful world of growing your own native plants from seed and contributing to genetically diverse seedlings.

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Toronto Based Resources

Pete Ewins shares his experience collecting seeds and growing native plants from his Toronto backyard.

Local seed exchanges are organized by

Seeds of Diversity (Seedy Saturdays),

NANPS,

and the Cliffcrest Butterflyway. 

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Prairiemoon.com is a great resource to double-check growing requirements

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A huge thank you to Kristl Walek and Graham Page for cracking hundreds of germination codes of woodland plants, shrubs, trees and difficult-to-grow plants and for sharing them with us @ wildplantsfromseed.com.   

(This wonderful site seems not to be available at this moment;-( 

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