Guide to Winter Sowing Seeds in Containers for Beginners

Sally Painter

Sally is a prolific non-fiction and fiction writer, who has appeared in multiple print and digital publications.

Published December 6, 2019

Examples of common Winter Sowing containers

You can get a jumpstart on next year's gardening by winter sowing seeds using containers. This method is ideal for gardeners unable to grow seeds indoors, especially in regions with short growing seasons.

How Winter Sowing Seeds in Containers Works

You can start preparing your containers to place outside after the first fall frost. Using containers for winter sowing seeds is often referred to as creating miniature greenhouses in the snow. You will use the containers to protect the seeds during the harsh winter that wouldn't ordinarily survive. These can be seeds from annuals or perennials.

More Seeds to Germinate

The container method of winter sowing seeds ensures a greater number of seeds will germinate when spring rolls around. The drink bottles and jugs are set outside without their caps and lids.

Exposure to the Elements

The seeds are cocooned inside the containers but are also exposed to the same inclement weather of snow, rain and ice as their less fortunate cousins on the ground from their perennial parents or their reseeding brethrens from annuals plants.

Creating Miniature Greenhouses with Containers

The container method of winter sowing utilizes various recyclable containers, such as two-liter plastic soda bottles, plastic water jugs, large plastic juice bottles, and plastic milk jugs. Tall containers work best since they have plenty of room for plants to grow tall.

Not All Plastic Containers Are Viable Greenhouses

Avoid using any plastic container that is not food grade plastic to avoid harmful chemical leeching into the soil and plants. Don't use plastic that sunlight cannot pass through. Clear plastic is the best option.

How to Test for Sunlight Penetration

If you want to use a colored plastic container, you can test it to see if sunlight can penetrate through the tinting. Hold the container in front of you. If you can see through the plastic, it's a good choice for a container. Most opaque milk jugs provide enough light, but white ones may block the light.

How to Select Plant Varieties

There isn't much guessing when it comes to selecting which plants are candidates for winter sowing of seeds in containers. You can often find this type of information on seed packets or online descriptions.

You can use seeds described as being able to withstand frost or suitable for fall plantings.
If you can direct sow the seeds in early spring or while there are still frost warnings, chances are the seed will thrive in your containers.
Packet instructions that require you to stratify or freeze seeds prior to planting are good choices.

How to Prepare Containers

There are a few things you need to do to prepare the bottle. Follow these steps to ensure your seeds have the best chance of survival.

Thoroughly wash the container with dish washing soap to get rid of all residue.
Remove labels on bottles and jugs.
Remove caps and lids. You won't need them.

Create Drainage Holes

You need to create drainage holes in the bottom of each container. You can use a knife or heat large sewing needle about 6" long with an open flame, from a lighter or candle. Be sure to hold the needle with a pair of pliers so you don't burn your fingers. The hot metal will slip easily into the plastic bottom to create a drainage hole.

Cut Containers in Half

You need to have access to the inside of the container. The easiest way is to cut the bottle or jug in half along the center point. You can leave one side or section of the bottle intact to serve as a hinge for easy closing, but it isn't necessary since the top can be refitted over the bottom by overlapping it.

Add Soil, Seeds and Water

You're almost finished. You need to add seeding soil mix to the bottom part of the bottom.

Fill 3"-4" of the bottom portion of your container with soil.
Gently press the soil down into the bottom.
Broadcast the seeds over the soil.
Add enough soil to cover the seeds and pat the soil down over the seeds.
Water so the soil is wet, being careful not to displace the seeds.
Return the top of the container and fit it over the bottom portion so it overlaps.
Use a waterproof marker and duct tape to create a label of the type of seed you planted.
Place the label along the bottom portion of the container.
Set the container outside on a flat surface, such as a patio or deck.
You can ignore the containers until the seeds sprout and begin to grow.
Once the weather is warmer, you can remove the top portion of the container until you're ready to transplant into your garden.

Transplanting Your Winter Seedlings

You will transplant your seedlings just as you would any other seedlings, depending on the type of plants you grew. Make sure you prepare the soil with amendments if needed.