7 Plants You Can Winter Sow in a Raised-Bed Garden as Soon as Your Soil Is Workable

What Is Winter Sowing?

Winter sowing is a wonderful way to get a jump start on the spring season. All you have to do is plant seeds directly in the soil even though it's not actually time for those plants to grow yet. The seeds will lie dormant in the soil throughout the coldest part of the year, and then sprout as soon as the soil warms up.

Lots of gardeners use old milk jugs left out in the snow to winter sow their seeds, but you can also practice winter sowing by planting directly into your raised beds. You just need the top 1 to 2 inches of your soil to be workable (not frozen, in other words) to winter sow. Luckily for us raised-bed gardeners, the top of those raised beds will thaw much sooner than the ground.

What I love about winter sowing is that I can start getting my garden ready for spring by gardening for just five minutes a day—sowing some spinach seeds one day, some carrot seeds the next, and so on. Plus, it mimics how seeds actually come up in nature. We're planting the way nature does, which means less work for us!

How Does Winter Sowing Work?

Picture a radish plant left in the soil too long. The root becomes starchy and inedible while the plant focuses all its energy on forming those green bean-like seed pods that will contain 100s of copies of itself. Those pods dry up and eventually drop to the ground. The withered leaves of the plant will crumble under the weight of the first snow and freeze in place for the dark months of winter. 

As the days grow longer in early spring, sunlight hits the garden bed once more, and the snow begins to melt. Each day, another layer of snow turns to water until all that we can see is dark, wet earth. What we can’t see are the radish seeds, the ones that were released from the pod as it split open in the soil. Those seeds have been enjoying a long winter nap. 

With each day, the seeds feel the warmth of the sun, sense the light overhead, and absorb more and more of the snowmelt. Until, finally, the seeds can’t take it any more. All that water and light and warmth causes them to simply burst open.

Plants actually have little internal clocks built into their DNA. They know how long they need to rest and what conditions (sunlight, temperature, and moisture level) they need to wait for before they decide it's time to grow. These little internal clocks prevent the plants from trying to sprout when the soil is still frozen over.

It's because of this mechanism that we can place seeds into cold, dark earth and trust that they'll grow when they're supposed to.

The Best Plants to Winter Sow in Your Kitchen Garden

These are my favorite plants to winter sow in the garden:

• arugula
• beets
• carrots
• lettuce
• purple mustard
• radishes
• spinach

Let's look at how to winter sow each of these plants in your vegetable garden.

Arugula Is a Winter-Hardy Green

Arugula is an incredible little plant. It can sprout in cool soil and survive hard frosts; it can push through extremely hot summers; and it can keep producing in the fall well after the first frost, basically until the ground hardens with frost.

You can space arugula seeds every 1 to 2 inches, or you can just scatter the seeds over the soil. If you want lots of yummy leaves for spring salads, sow those arugula seeds in the garden as soon as you can!

Beet Seeds Can Be Sown Well Before Your Last Frost Date

If you live in a warmer climate, the best time to grow beets is actually over your winter months. That's because they love cooler weather (45 to 65°F). For the rest of us, we can sow beet seeds in our gardens the minute our soil is workable in the late winter or early spring. Beets are cold tolerant, so you don't need to worry if you're expecting a couple more frosts for the season.

I typically plant about 9 beets per square foot. I use my seed spacing ruler to help me gauge the distance.

Carrot Seeds Do Great in Cold Soil

Winter sowing carrots is a great way to check a gardening task off your list before spring has even sprung! 

Carrots are a cool season crop, and they don't mind a little bit of frost one bit. In fact, a light freeze actually sweetens the taproot. Carrots need between 60 and 90 days of temps ranging from about 45 to 75°F to form their tasty little roots.

Carrots are so tiny that they're hard to single out for planting. I typically use a seed spacing ruler to help me spread them out. I plant every 1 to 3 inches, depending on how large I expect the taproot to grow. Your carrot seeds should germinate once the soil temperature goes above 55°F or so.

Lettuce Seeds Can Be Winter Sown

I've already sown seeds for my favorite salad blend, Rocky Top Lettuce Mix. I love it so much I just can't wait for it to sprout.

Lettuce loves growing when it's between about 50 and 70°F. As soon as the soil warms up enough for these lettuce seeds to sprout, these little plants will take off and be ready for the first leaf harvest very soon.

Pick a raised bed and scatter some lettuce seeds for the most amazing homegrown salad just around the corner.

Purple Mustard Is a Great Plant to Direct Sow in Winter

I had the prettiest purple mustard and giant red mustard plants that came up last year after being winter sown. Mustard plants do really well when direct seeded in the garden.

You can plant purple mustard seeds every 3 to 6 inches. I like to do rows toward the center of my garden beds since these will grow pretty tall. The only thing difficult about sowing these seeds is their size. Have you heard the Bible story about moving a mountain with faith the size of a mustard seed? Yeah, those seeds are really teeny tiny. In this case, if we have some faith in our winter sowing abilities, we'll end up with really big plants!

Radishes Are the Ideal Crop for Winter Sowing

Radishes are so easy to plant and grow in the kitchen garden. They love the cool weather and shorter days of early spring, and they can withstand frost and snow.

Space your radishes a couple inches apart (however wide you expect the mature root to be). I like to use my seed spacing ruler to make nice, straight rows. Your radishes should germinate as soon as the soil warms up to 50°F.

The ease of winter sowing radishes, carrots, and beets is one reason I plant straight into my raised beds instead of containers like milk jugs. Root crops as a whole don't transplant well, so I've found this method works much better for me.

Spinach Is the Perfect Leafy Green to Winter Sow

Winter sowing spinach leads to absolutely gorgeous and robust spinach plants. Spinach loves growing in temps between 45 and 75°F, and of course, it can handle colder temps and frost. A little frost actually sweetens up the leaves for you. That's one of the reasons spinach has long been a staple in greenhouses and cold frames over the winter.

Space your spinach seeds about 1 to 2 inches apart in staggered rows. You're well on your way to spinach smoothies!

Tips for Winter Sowing in the Garden

If you have a soil thermometer, you can use it to check the temperature of the soil in your raised garden beds. I usually winter sow when the soil is just under 50°F. When that magical moment arrives, keep these tips in mind.

Start With a Smooth Soil Surface

Rake the soil a little, break up any large clumps, and clear away any debris before you start planting so that you have a nice, flat surface. Most of these seeds are tiny, and you don't want them to get lost in soil pits and troughs.

Use a Planting Line

The best way to ensure your winter-sown crops come up in nice, straight lines in the spring is by using a planting line. If you don't have one, you can always use some twine strung between two yardsticks or stakes.

Use a Planting Ruler

I use a seed spacing ruler whenever I'm planting really tiny seeds—carrots, lettuce, spinach, mustard—in the garden. A trick I've learned for spreading out seeds is to pick up a small amount of seeds between my fingers and then rub my fingers together as I go down the planting ruler. This method typically only drops 1 to 2 seeds at a time.

Cover Your Garden to Speed Things Up

A simple cold frame or even just some frost cloth can help your soil warm up enough to sprout these seeds, extending your total growing time this spring.

Mark Your Spot

Don't forget to use some plant tags to mark where you've sown your seeds. Trust me. Spring may be just around the corner, but it's easy to forget where you planted something just two days ago.

Skip Watering Your Seeds In

You don't need to water your seeds in after you've planted them. Water is one of the things that tells a seed to wake up from dormancy and grow, but we don't want these seeds to sprout until the temperature is just right for them.

Time to Do Some Winter Sowing

I can't wait to see lots of little green shoots pop up in my garden, the results of all my "hard work." Seriously, though, I filled my garden with seeds that will soon be ready to grow by planting in 5-minute intervals each day. I used the setting sun as a prompt to go outside and sow one type of seed. As soon as I noticed the sun going down, I'd close my computer and rush outside. That's how I fit spring planting into my busy schedule between my work day and taking my kids to their evening activities. 

Hopefully, this encourages you that you, too, can accomplish so much in your garden in just five minutes a day this winter.