How to Winter-Sow Your Seeds

How to Winter-Sow Seeds: A comprehensive guide to starting vegetable seeds outside in the middle of winter. Includes how-to photos and supplies list.

New England can truly be one of the most magical places to live year-round but when it comes to the end of February and beginning of March, it’s a tough time. 

When gardeners in much of the South are prepping their garden spaces and planting seedlings, we’re still battling with consistent mornings of below-freezing weather and the occasional March snowstorm.  This is the only time of year I wish myself out of New England. 

Kyle and I are both dying to be building more raised beds, digging in the dirt, staking up tender tomato plants.  We’ve been talking about this stuff since early December.

So to combat the winter woes, we decided to try winter-sowing this year!

As I mentioned earlier this week, we planned out what we want to grow this year and bought the seeds already. Those are the first 2 steps for our veggie garden. 

This past weekend, we planted the first of our seeds. Not in the rock-solid frozen soil of course, but in up-cycled plastic water bottles that we’ve been saving since before Christmas. The bottles will act like mini-greenhouses outside, even in cold weather, to germinate the seeds and start the seedlings for planting once the soil warms up enough. This is called winter sowing!

How to Winter-Sow Your Seeds

Here is where I show you guys that it’s possible to start your seeds, outside, in the middle of winter.  Not everyone has space to house flats of seedlings indoors (including us) so take advantage of your yard, fire escape, rooftop, whatever, to get a head-start on spring.

1. First things first: You need to figure out what you want to grow. Then order or buy your seeds. We ordered ours this year from Baker Creek Heirloom Seeds. If you order from a seed catalog, please share your favorite source in the comments below!

2. Make a growing plan based on when your seeds need to be started and when the seedlings need to be planted. 

Some seeds will be sown directly into the ground.  Take good notes of when you can plan certain seeds. 

You’ll also need to know when your average last frost date is.  Everything you plant will hinge on this date. 

Here are two maps (for spring and fall frosts) that will help with this: average last frost date (spring frost) | average first frost date (fall frost). You can also check the Farmer’s Almanac for reliable dates.

3.  Get your supplies together.  Here’s what you’ll need:

• Translucent water or clean milk jugs or clean plastic 2-liter soda bottles
• Utility knife
• Hand drill with 1/4-inch bit OR a screwdriver and a flame
• Nutrient-rich soil, preferably organic (if that’s your thing)
• Duct tape or flashing tape
• Sharpie
• Sturdy outdoor table
• Sturdy wine or large, short plastic containers

4.  Using the utility knife, cut horizontally around the bottle about 6 or 7 inches up from the bottom.  Cut almost all the way around, leaving a hinge so that you can easily open and close your containers.

5.  With the hand drill or a hot tip of a screwdriver (hence the flame), poke holes in the bottom of the jugs.  The soil will need some good drainage.

6.  Add 3 to 4 inches of soil then water the soil so it starts to drain out the bottom. You’ll not want to do this on your kitchen counters. We made a workspace in the garage for this project. Once the water has drained, lightly press the soil down – do not compact it.

7.  Plant your seeds according to the directions on each of the seed packets. Some will need to be planted deeper than others so pay attention to the instructions. Cover them with soil and lightly press the soil down – do not compact it.

8.  Close up the jugs and tape them closed in a few spots. You don’t need to tape the whole way around the jug as rainwater will need to get in and you’ll need to easily open up the jugs in a few weeks without disturbing the soil too much.

9.  Using the Sharpie, write the type of seeds you planted and the planting date on each jug. This is an important step. You need to know which jug has which seeds when you go to transplant the seedlings.

10.  Set your jugs outside on a table either in large, shallow plastic containers or tie the handles of the jugs together to prevent them from flying around if it gets windy. You’ll want to set the table up in a space where you get maximum sun exposure during the day.

Know Your Planting Zone

So the reference point we used to teach ourselves how to do this comes from A Garden for the House, a gardening blog based out of the Hudson Valley in New York.  The Hudson Valley is located about 30 miles west of where we live and perhaps 15 or 20 miles south. In spite of how close this is to us (north-south-wise), it falls in a different Zone than us (6b). 

So when I say that you need to know your Zone, I really mean it. The author, Kevin Lee Jacobs, is able to start his winter seeds a full month in advance of us and if you’re further south, you should be able to start winter-sowing in December.

What We’ve Planted So Far

After making our garden plan and thereby completely overwhelming ourselves with “OMG we don’t have enough jugs for all of these seeds!”, we realized that because many of the seedlings need to be planted at different times, we can stagger the winter-sowing. 

That will give us the chance to re-use the jugs for new seeds in a few weeks while we drink more water and gather more jugs. Our first round of sowing included peas, broccoli, Brussels sprouts, and spinach. These are all hardy, early spring veggies that will be able to survive cold nights/mornings and thrive off of the warming days and extra sun that will be here in mid-March.

Looking Ahead

In the coming weeks, our next round of seeds will be sown and set outside. Those will include carrots, a couple different types of lettuce, and a few types of perennial flowers – yes, you can grow flowers (super cheaply) from seed!! 

Last summer I shared my garden journal with you and this weekend, I’ll work to put together our sowing/seedling schedule to share with you next week. This will be the ultimate key to help us stay organized when it comes to keeping track of the 20+ different types of seeds we bought this year.

What Are You Planning/Planting This Year?

What are you guys planning to grow this year? Or have you started your plantings yet? I’m dying to know!!