The Ultimate Beginner Guide to Winter Sowing
Whether you want to stay busy in the garden in winter or sow seeds that are tough and resilient, winter sowing is the answer. This process ensures your seeds emerge as soon as conditions are just right, ready to transplant straight into the ground. Gardening expert Madison Moulton explains everything you need to know in this beginner guide.
Contents
Winter sowing is exactly what it sounds like: sowing seeds in the middle of winter. This method allows you to start seeds outdoors when it’s still cold (or even snowing). If you have limited indoor space for sowing or lack the necessary materials, winter sowing is a great alternative.
The seeds are protected by homemade containers that act as mini greenhouses. The seeds remain in the soil until the spring warmth naturally encourages germination. With no need for heating mats or grow lights, the seeds will sprout and grow on their own. From there, they can be transplanted into the ground without any hardening off, as they’ve already acclimated to outdoor conditions.
For winter sowing to be successful, you need to live in a pretty cold climate. The soil should remain cold enough to prevent premature germination, as any seedlings that sprout too early will be killed by the cold. January is typically a good time to start winter sowing, but those in very cold areas can still sow in February or even March without issues.
The Benefits of Winter Sowing
You might be wondering why you should try winter sowing instead of starting seeds indoors or simply waiting until spring.
For one, it gives you something enjoyable to do during the winter months. When it’s snowing outdoors, there’s not much to be done in the garden except cleaning your tools and reorganizing your shed (probably for the second or third time). Winter sowing is a fun activity that satisfies your gardening cravings without much effort. It’s also simple enough to do with kids, making it a great way for the whole family to get involved.
But beyond keeping yourself busy, there are plenty of benefits for the plants and you, too:
- There is no need to harden off seedlings before transplanting them.
- Seedlings are better equipped to handle the stress of transplanting.
- Winter sowing saves on indoor space.
- Outdoor sowing takes care of the cold stratification process for seeds that need it.
- Recycled containers save money.
- You need very little equipment to get started.
Starting Seeds Indoors vs Winter Sowing
If you’re deciding between starting your seeds indoors or winter sowing, neither method is inherently better than the other. It really depends on your situation and which method you prefer.
For those with limited indoor space, it’s not ideal to crowd your surfaces with growing trays and grow lights for weeks or months during the winter. Winter sowing frees up your indoor space while providing the same end result come spring.
Winter-sown seedlings are largely out of sight during the day. If you’re someone who might forget to check on outdoor seedlings if they’re not nearby, indoor sowing may be better for you. While winter-sown seedlings don’t require much maintenance, they may need attention in dry or humid climates during the winter months.
Starting seeds indoors gives you more control over growing conditions. While this isn’t necessary for all plants, it can be helpful for more delicate plants with specific germination needs. It’s also better for warm-season crops, like tomatoes or eggplants, that require heat to germinate. In cold climates, it may take a while for the soil to warm up enough in spring, so indoor sowing gives you an earlier start.
The biggest difference comes at transplanting time. Indoor seedlings need to be hardened off before transplanting to help them acclimate to outdoor conditions. Winter-sown seedlings are already outdoors, so they can be transplanted as soon as the weather warms up.
Ultimately, the method you choose depends on your preferences. You can even try both! Keep your fussy plants indoors while sowing the rest of your seeds outdoors for the best of both worlds.
The Best Seeds for Winter Sowing
Technically, you can winter sow almost any seeds you like. Due to the cold, seeds will only germinate when it’s naturally warm enough, so the winter cold isn’t usually a problem—though it’s important to watch for sudden cold snaps after germination.
That said, some plants are less risky to winter sow than others. If you’re a beginner and want to play it safe, stick with cold-hardy crops that can tolerate temperature fluctuations or any seeds that require cold stratification to germinate.
Choose tough flowers like coneflowers, yarrow, and black-eyed Susan. In the veggie garden, brassicas like broccoli and cabbage are popular choices. A variety of herbs are also suitable for winter sowing, including sage, oregano, and dill.
Winter Sowing Methods
One of the benefits of winter sowing is using recycled containers to start your seeds. Not only does this save money, but it’s also a great way to recycle waste and prevent it from ending up in a landfill.
There are various containers you can use. The most common ones you’ve likely seen online are clear milk jugs, but soda bottles or plastic tubs also work well. If you don’t have any recyclable containers on hand, old plastic Ziploc bags can save space and work just as effectively.
Regardless of what you choose, make sure to clean the containers thoroughly before adding any soil. You don’t want to introduce anything that could negatively affect germination or growth, as you’ll only discover issues when spring arrives.
What You’ll Need
Once you’ve got your containers ready, you can grab a few other supplies, including:
- High-quality potting mix
- Seeds
- Watering can
- Skewers (if using plastic bags)
- Marker (to label containers)
- Duct tape
How to Winter Sow
The winter sowing process should make seed starting stress-free. This is ideal for beginners, especially if you’re prone to fussing over your seedlings and killing them with ‘kindness’ by accident. If you’re looking for a set it and (almost) forget it seed-starting option, follow the steps below.
Prepare Your Containers
To prepare your plastic container, cut a horizontal line into the side (without removing the top completely) to provide access to the inside. Cut a few drainage holes in the sides and bottom to allow excess moisture to escape. Removing the cap will provide ventilation.
For plastic Ziploc bags, you’ll also need drainage holes in the bottom. Cut off the corners (but not too much, or the soil may spill out) and make small slits at the bottom to prevent water from pooling. Like milk jugs, leave a small gap at the top for ventilation. You can use a clothespin to hold the bag open if needed.
Next, fill the container with your potting mix. The soil layer should be at least 3 inches deep. Moisten the soil with your watering can before planting. This also allows you to check the drainage and adjust if necessary.
Plant
Make sure you have enough containers prepared for the amount of seed you want to sow. Then, it’s time to get planting.
Some gardeners make the mistake of sowing too densely in the containers or simply sprinkling them over the soil and hoping for the best. Even when winter sowing, it’s important to follow the instructions on the seed packet, especially when it comes to sowing depth. Planting too shallow or too deep can hinder germination and ruin your winter sowing efforts.
Sow your seeds according to the spacing and depth instructions for that plant. While you can plant densely and thin out the seedlings later, you don’t want to heavily overcrowd the container and hinder early growth. After sowing, label each container or bag to remember what you planted where.
After planting, replace the top and close off the side with duct tape. This will stay closed for most of winter, removed when plants start to sprout and you need to give them a little more sun. Seal Ziploc bags closed, leaving a small gap in the top.
Plastic bags can flop over outdoors, impacting ventilation and making it difficult for young seedlings to grow. To keep them upright, stick a skewer through the top of the bag and rest it on the sides of a larger container to keep them upright.
Choose a Location
After planting, put on your coat and boots to set your containers outside. Place them in a full sun position, and don’t worry about elements like rain or snow—you want this kind of exposure. Keep the containers as close to your home as possible so you don’t have to walk too far to check on them.
Wind usually isn’t a major issue since the containers are protected. However, if the wind is strong enough to knock over an entire milk jug filled with soil, provide some extra protection. You can use a screen to block the wind or place the containers inside a crate to keep them sturdy.
Watch Closely
While your winter-sown seeds don’t require much maintenance, you should monitor them regularly.
If you live in an area with frequent rain or snow during winter, check that the soil is draining properly. If necessary, raise the containers slightly off the ground to improve drainage. If it doesn’t rain or snow often, check the soil regularly and water as needed to keep it moist but not waterlogged.
Watering is the only real maintenance task (unless your containers are already exposed to rain or snow). This usually happens toward the end of winter or early spring, so don’t worry if no green growth appears for several weeks.
Transplant
The final step in the process is transplanting. Once your plants have true leaves and all danger of frost has passed, transplant them into their final home in the garden. After transplanting, treat them like any new plant in your garden—tough and ready to handle the elements.
