Winter Sowing Without Milk Jugs (Clamshell Containers Work!)

A Simple Winter Sowing Method Using Recycled Containers

Most winter sowing tutorials assume you have milk jugs, but how do you winter sowing without milk jugs? I really wanted to winter sow, but we get our milk from the neighbor’s cow! So no milk jugs. What to do! Use plastic veggie containers, clamshells!

I almost missed the window for winter sowing because I did not have milk jugs. So I did some research and found this winter sowing article from Rutgers University. Rutgers University’s winter sowing guide explains how to use different containers, not only milk jugs but also plastic food container shells.

Use What You Have: Veggie and Fruit Clamshell Containers

Plastic veggie clamshell containers are great mini greenhouses. The fruit shells I used are nice, like the large strawberry containers, which have slits and holes in them! Bonus! The large hinged containers are the best for easy access. Use those milk jugs if ya got em!

Why they work:

• Clear lid = mini greenhouse
• Hinged = easy access
• Plastic = cold tolerant
• Protects seeds during Kentucky freeze–thaw cycles

Step-by-Step Guide to Winter Sowing in Recycled Containers

This method works for clamshells, milk jugs, and other recycled containers

• Clean the containers: Wash your recycled containers thoroughly with soapy water. Choose ones that can hold at least 3 inches of soil and provide enough headspace above the soil for seedlings to grow. Ensure the tops are clear to allow light to pass through.
• Add drainage: Poke or drill several drainage holes in the bottom of each container to prevent waterlogging and seed rot.
• Ventilate the lids: Create small holes in the container lids to let in rain and moisture. For milk jugs or soda bottles, simply remove the lids entirely to allow air and moisture circulation.
• Modify non-opening containers: If using a container without an easy-open top (like a milk jug), cut around the middle about three-quarters of the way, leaving an uncut section to act as a hinge for flipping open the top.
• Prepare the soil: Moisten your potting mix (avoid using garden soil, as it compacts and restricts root airflow). Fill the container with about 3 inches of the moistened mix.
• Plant the seeds: Scatter the seeds on top of the soil, then cover them with additional potting mix according to the seed packet instructions.
• Label clearly: Mark your container with tape or like I did- cut a yogurt container and write seed names on it with a permanent marker.
• Seal the container: Close or tape the container shut securely—3M clear duct tape works well for this.
• Place outdoors: Set your containers outside in a location that gets natural moisture (like rain or snow) and sunlight. Start with a south-facing spot for winter, but as spring arrives, relocate them to an east- or west-facing area to avoid overheating the seedlings on warm days.
  

What to do after the seeds are sown?

Once your containers are outside, they require minimal maintenance. It’s a good idea to check them occasionally to ensure there is condensation inside. If you notice a lack of moisture, you may need to add some water and adjust your mini greenhouse setup by either increasing the number of holes in the container lid to allow more water in or sealing some holes to retain moisture.

This gradual exposure will assist in hardening off your plants, preparing them for outdoor conditions.

Why Winter Sowing Works

Winter sowing mimics the natural growth cycle by using protective containers that function like mini-greenhouses. This technique enables seeds to undergo crucial cold, moisture, and temperature fluctuations, a process referred to as stratification. Consequently, germination takes place at the ideal time, producing strong seedlings without the necessity for artificial lighting and allowing for more space indoors.