(I’m back from Christmas vacation! This is the second part of a series on growing native plants from seed. If you need to read part 1 you can find it here.)
In the first post I mentioned the term Winter Sowing and promised to explain it. Well here goes!
Winter sowing is the native gardener’s way of using mother nature to work for them. This is what makes it so easy – you will be using nature’s natural process. You plant your seed and let the weather do all the work!
Why should you winter sow? Because it is so easy. Imagine having flower beds full of perennials without needing grow lamps, heating pads or seed-starting kits. These perennials will only cost you the price of seed, soil and a pan.
How to get started
The key to winter sowing is purchasing native seeds that would naturally grow in your area. You can winter sow with non-native seed, but you risk the winter being too harsh and killing the seed. When you grow natives in your area you have an advantage in that they are already hardy enough for your winters.
Note: Most native plants can be winter sown but do not attempt this with butterfly weed (Asclepias tuberosa) or false indigo (Baptisia spp.) as these plant grow a deep taproot making transplanting impossible. For these plants it is best to direct sow them.
A good rule of thumb is to look for plants that grow in your growing zone or a colder growing zone. For example, my hometown is listed as zone 6. If I want to winter sow, I should purchase seed of plants that grow in zone 6 to zone 1. (Don’t know your growing zone? The USDA has a handy map that can help you).The key to winter sowing is purchasing native seeds that would naturally grow in your area. Click To Tweet
Many seeds have special seed coats that protect them. These seed coats need specific conditions for them to break down and allow the seed to grow. Some seeds need warm temperatures (think Big Bluestem grass), some need fire (the Giant Sequoias), some need to pass through an animal’s gut (the Red Bud), and some need a specific amount of cold weather (like the Black-eyed Susan). Winter sowing simulates some of these conditions.
The first step in winter sowing is purchasing the correct seed. You already know to get seed of plants that grow in your area, the next step is to look for seeds that need cold weather or warm weather to germinate. When considering seeds look for the words ‘cold-treatment’, ‘stratification’, ‘scarification’ or ‘needs oscillating temperatures.’ These terms may seem intimidating, but they are just what you need.
The next step is to gather your supplies. Get some containers. Some people use milk jugs, some use plastic carryout packages. I like to use disposable aluminum trays with plastic lids found in the baking isle. I reuse these year to year. You will also need a fluffy potting soil mix, scissors, a permanent marker, and duct tape.
How to winter sow
Wait until winter has arrived. In my area this is normally around Christmas, but it can vary. You want it to freeze at night and be cool during the day.
After you have gathered your supplies, find a place to work where you can make a mess (the dirt always goes everywhere for some reason). Take your container and make a mini-greenhouse.
If you are using milk jugs:
Cut the milk jug in half on the horizontal right below the bottom of the handle. This leaves the bottom as a type of ‘pot’ to hold your soil. It’s OK if you cut the top off, this will be the ‘lid.’ Remove the cap and throw it away.
If you are using aluminum pans:
Take the pans out of the packaging. Poke a few holes in the lid and set it aside.
Once you have the ‘lids’ removed fill the ‘pot/pan’ with soil. Place 2 to 3 inches of soil into the container.
Water the soil. Mix the soil and water and then let it sit so the water soaks in evenly. I let it get pretty soupy.
Once thoroughly wet, sow your seeds. I like to surface sow all my seeds and gently pat them into the soil. I am not pressing them into the soil, just gently ensuring that the seed and soil have good contact.
Place the ‘lid’ back on the container. For milk jugs duct tape comes in handy for this. You can use the tape to hinge the lid. The lids must have some holes so that hot air can escape.
LABEL THE CONTAINER! This may be the most important step. Nothing is worse than seeing your seedlings sprout but then having no idea what they are! I use permanent marker for this. I write the name of the plant on a piece of duct tape and then stick it to the container. Place the label on the side of the container that will get the least amount of sun – one year all my writing faded and it was not fun.
Poke holes in the bottom of your container and allow them to drain. I like to do this last because it makes less of a mess. I let my containers drain over my laundry room sink.
Take your containers outside. Place them out of direct sun and strong winds, where they are safe from winter activities. I put them on the shelves that house my plants in the summer. Don’t worry if they get rained or snowed on – they will be fine.
Now, wait and enjoy some hot chocolate. Mother nature will work her magic on the seeds and the soil. It will freeze and thaw, scratching the surface of the seed and sending signals to the seed that germination should happen soon.
When should I open the containers?
Although winter sowing takes much of the hassle out of growing plants from seed, you will still have to do some work. As spring approaches your seedlings will need a tiny bit of help from you.
When you notice that spring is near (daffodils begin to bloom and the days are warmer) but the nights still drop below freezing, start checking the containers. In zone 6 this is usually mid March. When the soil dries out remove the ‘lid’ and water it. Put the lid back on.
You will start seeing green in the containers. Your seed is germinating and your baby native plants are growing! When this happens, keep checking the soil. Keep it moist but not soaking wet. As the days heat up you can remove the ‘lids’ during the day and replace them at night. After a few weeks in April, I remove the lids completely and let the seedlings enjoy the spring air.
Your need seedlings can’t stay in their containers forever. Most seedlings start with a single or double leaf. These first leaves are called cotyledons. I leave my seedlings alone until new leaves replace the cotyledons. I start transplanting mid May in my zone. I prepare the place where they will live by clearing the soil and then transplant them. I also water the container heavily that morning – this allows the seedlings to get their fill and makes the soil easier to separate.
When transplanting these seedlings it’s important to be gentle. The root systems of each plant will be entangled in the container. If you have a fluffy potting soil, it will be easy to remove the seedlings and tease the roots apart. I hold the plants by the soil because holding a seedling by the stem can easily break it and kill the seedling. An older plant can take being broken but a seedling cannot.
I also try to transplant on an overcast day so that the seedlings will not dry out during the process.
There you go! That’s the process of winter sowing. It is an easy and cheap way to get lots of native plants for your prairies, butterfly gardens or woodland settings!
Is winter sowing too much work for you? Well that’s OK because I can help with that! Stay tuned. Next week I’ll discuss direct sowing.