Winter Sowing Seeds
I’m all about taking the easy way out. Laziness rocks!
You know what I mean, right?
We gardeners are the opposite of lazy, really. I mean, if we were actually couch potatoes, the last thing we’d be doing is gardening. However, why make it harder than it needs to be?
Before I’d ever heard of the winter sowing method for starting garden seeds, I used to set up an elaborate light system and shelves to hold tray after tray of little seedlings. I’d painstakingly care for them and when they got leggy, move them between window sills for maximum light exposure, and then spend weeks moving them outdoors for increasing amounts of exposure each day in order to harden them off.
Still, after all that meticulous care, many of those hard-earned seedlings would succumb to damping-off and others would inevitably be too fragile to survive and die when transplanted. The alternative was to purchase seedlings from a nursery, which cost at least ten times as much (I need a lot of plants) as buying seed, and they were still pretty fragile.
I was thrilled to learn about Winter Sowing from Trudi Davidoff! It sounded so easy, so carefree, and so not all over my kitchen and mudroom all through March/April/May!
Winter Sowing Instructions
You can use any type of milk or juice jug, takeout containers, or any large, plastic containers with deep bottoms and translucent (they don’t have to be completely transparent, but shouldn’t be opaque) tops. Don’t use old bleach bottles or anything where the plastic could have absorbed noxious chemicals, but everything else is free game.
The video below demonstrates all of these steps in case you’re having a hard time visualizing them.
1. Use a screwdriver or other sharp implement to stab 4+ holes in the bottom of the milk jug for drainage.
2. Cut horizontally, about 5″-6″ up from the bottom, across three sides of the milk jug, leaving the area with the handle, intact. The intact side acts as your hinge.
3. Fill the bottom of the jug with at least 3″ already moist potting soil.
4. Plant your seeds (heirloom are best), then label your jug and tape it up.
5. Leave the cap off of the jug (or if you’re using takeout containers, take the knife and poke several slits in the clear plastic lid). This is for air transpiration. If you don’t vent the air that is heated by the sun (greenhouse effect) you’ll bake your tiny seedlings to death.
6. Place your seeds outdoors in a safe spot. I place mine along a south-facing, wind-blocking wall, but you don’t have to. The beauty of the winter sowing method is that your seeds don’t have to be babied!
Your jugs will freeze and thaw repeatedly as winter becomes spring. This action of freezing and thawing out helps loosen the seed’s protective coating. Mother nature knows just how to get seeds to germinate, and your little seeds know when it’s safe to pop up.
If you live in an arid climate like me and don’t get snow for awhile and the soil seems dry, definitely add a little water. (I just place my jugs on baking sheets filled with water, and they soak it up like a sponge without disturbing the soil or seeds inside.)
Also, if you have a warm spell and the seeds sprout too soon, you might want to throw a blanket over them (or bring them inside) if the temperatures dip to below freezing for very long. This year, we had temperatures in the 60’s and 70’s during March and all of my seedlings began to grow, and this week we have snow forecasted all week.
I think I could probably pop the caps back on overnight and cover my row of milk jugs with an extra layer of plastic (then remove them again in the morning). But I don’t want to take any chances, so I brought them all in and they’re on my kitchen counters. I put them back outside during the day and just bring them in during the night when it’s officially below freezing.
Hopefully your weather isn’t as bipolar as mine!
Once winter-sown seeds begin to reach the top of their containers, it’s time to pull back the covers and fully harden them off. Just peel off or cut through the duct tape, pull back the milk jug tops (leave it attached in case of a freak freeze) and let them get all the sunshine and fresh air they can, while still offering a little wind protection.
In case of a freeze, just replace the milk jug tops and cover with a sheet of heavy plastic. After a week of full exposure, your seedlings are ready to go into the garden.
I actually start exposing mine about a month before our average last frost date and then I plant mine in the ground about two weeks later (still two weeks before our average last frost date), but I plant them with milk jugs over the top of them, like a mini greenhouse, so they’re protected. I finally remove the milk jugs about the first week of June, when I’m finally sure we will not have any more freak freezes.
Northern Utah weather is not trustworthy.
By June the plants are growing happily through the tops of the milk jugs, so I just pull them off very carefully. All of that is extra work, but it extends my growing season by at least a month, so I think it’s worthwhile.
What Should I Grow?
You can buy packets of seed just about everywhere these days, including the dollar store (I’ve tried them with great germination rates and plant quality). Nevertheless, I recommend paying a little more and purchasing high-quality, organic heirloom seeds.
You won’t be able to find heirloom sweet corn. It doesn’t exist. All sweet corn is hybridized or genetically engineered because corn was originally a starch and not sweet — think livestock feed.
You may also want some specific varieties that are not heirloom, which is fine. But you won’t be able to save their seeds and grow new plants that are true to the parent plants. Such is the nature of hybridized seed.
Saving seeds will save you a tidy bundle each year. Plus, the way our political situation and economy are going, there may be a time when you will be unable to purchase new seeds and will have to rely on saving your own seeds.
For the most part, heirloom vegetables are also tastier and more nutritious just because God is so much better at making things than mere mortals in laboratories. I do love sweet corn and some of the beefsteak tomato varieties, and I love that many of the hybrids are resistant to diseases, but I reserve most of my garden space for heirloom produce, and I save seeds every year.
I also prefer organic seeds that have not been exposed to chemicals, because that’s how I like to grow my own garden. I put a lot of effort into growing vigorous, naturally strong plants so I don’t have to deal with diseases or pests.
When determining whether a seed variety is a good winter sowing candidate, first make sure the hardiness zone is appropriate. If it’s naturally hardy in your zone, odds are good that it’s a good option for winter sowing.
Seeds that need to be stratified or scarified respond well to winter sowing. Stratification is the process of using prolonged periods of cold temperatures to break dormancy. Scarification is the process of manually weakening the hard, protective seed coating, which can be done by scratching the coating, or is done in nature by alternating periods of freezing and thawing.
Winter sowing allows both stratification and scarification to happen naturally, and is the perfect solution for seeds that require them.
Corn and beans don’t transplant very well, so you’ll just have to wait and direct-sow them after your average last frost date. Lettuces, chard, spinach, peas and other cool season crops are great candidates for winter sowing, but they won’t give you a huge advantage, since you can just direct-sow them into your garden in very early spring/late winter anyway.
In fact, I don’t usually even gather seeds from my lettuces, I just let them self-sow and they come up on their own during the late winter/early spring. I often have little lettuces poking through patches of snow in March and we’re enjoying it with our lovely asparagus by April.
Only sow seeds of tender (the seed packets will say that they should be planted after the last frost date) plants that will transplant well. Tomatoes, peppers, cucumbers, all types of melons, summer and winter squashes and most herbs and flowers transplant well so they are good candidates for winter sowing.
However, they are also more susceptible to cold temperatures, so you’ll have to watch your spring temperatures carefully. If they germinate and then freeze, they’re probably goners. They’ll be more resilient than nursery plants, but they’re still tender annuals.
If your temps only get down to near freezing, they’ll be okay outside with a cap placed on the jug overnight and an extra layer of plastic or a blanket. But if it gets to below freezing, you should bring the jugs inside and then replace them back outside as soon as temperatures allow. You don’t want the caps on during the daytime and you don’t want to leave the jugs inside very long to avoid problems with overheating and damping-off.
When Should I Sow My Seeds?
For those of us living in the Northern Hemisphere, it’s a good idea to wait until after Christmas to start our winter sowing. That’s a busy time for me, so I usually wait until February (which is also when I start really missing and craving gardening, so it’s perfect).
Just don’t winter sow your seeds too early in the winter months because a warm spell could come along, followed by severe freezing, and your seeds could germinate and then die. That would be sad!
Even if you wait until February or thereabouts, you still have to keep an eye on the weather. If you have a warm spell in March, followed by freezes in April, you’ll have to take a little extra care of any non-cold-hardy plants that have germinated (like tomatoes, peppers and squashes).
You can start them as late as up to just a couple of weeks before your average last frost date. Even just a couple of weeks will give you a head start on directly sowing them into the ground.
The Benefits of Winter Sowing
1. You don’t need special grow lights, heat mats, fans or shelving units or any expensive, specialty equipment.
2. You can recycle and reuse things that would ordinarily have gone into the landfill.
3. Recycling and reusing saves the planet, it saves you money, and you’ll also save on your electric bill.
4. This sort of “tough love” approach to seed starting (although it’s really just mimicking the natural process) creates plants that are vigorous and naturally strong. They are much hardier than seedlings purchased from a nursery. You don’t even need to harden them off and you’ll still lose fewer when transplanting.
5. At the nursery, you’re limited to selections they decided to grow. When you grow your own seedlings, you can choose all of the varieties you want.
6. The chillier temperatures and fresh outdoor winds prevent the damp-off which often causes young seedlings to fail.
7. Winter sowing takes a whole lot less time than tending seedlings started indoors.
Save these instructions for ‘Winter Sowing’ of garden seeds for later!
Have you tried winter sowing your garden seeds before? We’d love to hear about your experience in the comments below.