Winter Sowing Adventure

It's that time of year when I start getting super antsy and can't wait to start planting. Our area is a zone 5, we have about 90 solid planting days. That means the planting season for most annuals doesn't start till May/June and makes for very long winters!

Thankfully there are some flowering plants that will grow and thrive in cooler weather and even take a light freeze. These plants are known as hardy annuals and do extremely well when planted in the fall. They include Larkspur, Bachelor Buttons, Love-in-a-Mist, and Sweet William to name a few.

Unfortunately I did not have a full understanding of hardy annuals before winter set in and I missed my planting window. In my desperate search to find some way to get a head start on my planting and have flowers earlier in the season, I came across a method called winter sowing.

Have you heard that term before? Although having heard the term before, I hadn't really looked into it much. I decided that now was a good time to research it.

Guess what? It's pretty much exactly what it sounds like, seeds are planted in the middle of the winter. Doing this helps them to develop a stronger root system and flower earlier. Another advantage is the plant grows outside and does not need to be hardened off.

Well that's all fine and dandy for areas that aren't covered in ice and snow like Narnia but what about us that are?

milk jugs with winter sown seeds in snowbank

Winter Sowing is still possible! It just takes a little more preparation and planning. So after a good amount of research this is what I came to.

The first step would be to gather plastic milk jugs to plant in. The milk jug will hold the dirt and help protect the seed from any hungry birds. It will also act as a mini greenhouse when the weather starts to warm.

I needed one jug for each type of plant. Thanks to some of my neighbors, I was able to gather more than enough in a short time.

Empty milk jugs

The next step was to decide what plants to plant in the milk jugs. I know that seems a little backwards and you are probably right. It makes more sense to pick plants first but I decided to start collecting milk jugs while narrowing down what seeds to use. It makes it easier for me to be patient if I have a problem to solve while waiting.

When it comes to picking plants for winter sowing, look on the seed packet for phrases like "can take light frost", "hardy annual", "needs prechilling", "plant as soon as soil is workable", or "plant in early spring while still cool". If there are plants that have reseeded themselves in your yard these are also good candidates for winter sowing.

For my experiment, I narrowed the plants down to phlox, sweet william, madam butterfly snapdragon, white mignonette, calendula, stock, strawflower, clary sage, sweet pea, dusty miller, black eyed susan, chocolate lace flower, love-in-the-mist, bachelor buttons, and orlaya. While some of these plants are iffy in my area. I figured it was worth a try.

drilling holes in the bottom of a milk jug with a drill.

Now that I have my milk jugs and know what seeds I'm using, it's time to prep the milk jugs for winter sowing. The first step is to make sure they are clean. It wouldn't do to have some nasty mold growing in with the seeds. Once the jugs are clean, they need some drainage holes drilled. Most seeds don't like soggy soil.

We used a drill bit to put about 8-10 holes in the bottom of each jug.

Milk jug cut in half with one corner still attatched

After the holes are drilled the milk jug needs to be cut in half horizontally. I made sure to not completely separate the top from the bottom but to leave a small section connected to act as a hinge. Leaving the hinge on will allow me to open up the mini greenhouse after the seeds have started sprouting and keep the seedlings from burning up.

I used a box cutter to cut the jug in half right at the point where the bottom of the handle meets the jug. This leaves a good space for the 3-4" of soil needed to plant the seeds.

Filling cut milk jug with 2 to three inches of soil.

Next comes planting the seeds! I did three rows of three in each jug for a total of nine plants. I usually plant the seeds a little deeper than they are tall. Some seeds actually need light to germinate and those ones I pressed gently into the top of the soil. It's important to read the seed packets to know if the seed needs light or not.

Spraying the soil with a spray bottle to moisten the soil.

Once planted, using a water bottle to spritze the seeds helps make sure they have enough moisture without dislodging the seeds.

half of a milk jug filled with soil and labeled with a phlox plant tag

The next step is very, very, very important! Labeling each jug once I finished planting to helps to avoid confusion later on. I used waterproof plant tags to put in the jug and then also wrote the plant name on the top of the jug. The hope is one of them will survive the spring wetness and I'll know which plant is what.

Milk jug with top replaced and Phlox written on the top.

For the milk jug to act as a greenhouse it needs to be sealed back up. I used duct tape to seal the cut and help keep the warmth in. It is important to discard the lids from the milk jug so that rain or snow can get in and keep the soil from drying out. It also keeps the inside of the jug from heating up too quickly and the seeds sprouting too early.

Phlox milk jug bottom and top attached with duct tape.

Now that the milk jugs have drainage holes, the seeds are planted, jugs labeled and taped back up it's time to put them outside. I picked a spot in my yard that, right now, is mostly shaded by the fence during the day. As the days get longer and the sun shifts they will be in the sun and should warm up nicely. Nothing needs to be done except checking on them every once in a while to make sure they haven't dried up. To do that I'll use a spray bottle through the top.

Milk jugs labeled and taped sitting in a snow bank.

That's all there is to winter sowing. Hopefully they will all take. If they do I'll have a fun time finding a place for them all. It is nice to have something to do during the worst part of winter. I'll post an update in a couple of months when the weather warms and they have hopefully sprouted.

Until then happy dreaming of gardening.