Cold Stratification

Sometimes the idea of planting seeds and growing a garden can be daunting—we get that! Do I have the right soil? How much light does a plant need? Am I watering too much? Too little? When do I start this type of seed? Why is my new plant dying?! So if reading a blog about cold stratification is making you get up and run out of the room, wait! It’s not so bad.

Cold stratifying is essentially tricking a seed into thinking that it went through winter when it didn’t. Really, that’s it. Lots of plants don’t need to go through this process. Typically, an annual (which means plants that go through their entire lifecycle in one year) don’t need it. If you want to grow zinnias or sunflowers, you are all set. But many perennials (plants that come back year after year) do need cold stratification to get growing in the spring. Some examples are butterfly bush, fuchsia, catmint, evening primrose, black-eyed susan, lavender, wildflower mixes, and there are lots more. A good seed packet will tell you on the back if this step is necessary.

So if you are holding a packet that says to cold stratify the seeds, we can help.

For the OCHM Garden we are cold stratifying lavender and St. John’s Wort. You can see how we did so in this video.

What You Need

• Seeds
• Sand
• Water
• Plastic Ziploc bags
• A Sharpie or pen for labeling
• A bowl
• A freezer
• Patience

Steps

1. Place some clean sand in a small bowl. Add some water to soften the mixture until you can form a ball with the sand/water mixture and it holds its shape.
2. Mix in your seeds to the mixture. You can add as much or as little seed as you’d like. And you can’t hurt the seeds here so really mix them up. If you are doing seeds from more than one packet, you’ll want to make separate mixtures.
3. Put the whole mixture into a bag, and seal tightly. Use multiple bags for multiple mixtures.
4. Label each bag with the type of seed and the date. Nice and big so you can see it easily.
5. Place in the refrigerator for 1 month before planting. The water from the mixture will keep them hydrated and the seeds are now thinking they are going through winter. When you take them out, they’ll kick into gear once you plant them.

Rarely, a seedling may start to sprout in the bag in the refrigerator. If that happens, take out the mixture and pot it up. You can check out our Seed Starting post to see how!