Winter Sowing Basics

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Winter sowing is such an easy way to get your garden growing.  It requires very few supplies and very little time.  Here are the basics to get started winter sowing.

Benefits of Winter Sowing

In the wild, a plant goes to seed and those seeds typically drop to the ground.  Then the seeds lay there and get rained on, snowed on, and have to wait until spring.

When we winter sow sees, we’re mimicking that process, but with a little improvement.  Inside the milk jug, the seeds are protected from the elements, and they also get a little bit of a greenhouse effect.

Winter sowing also helps to raise hardier seedlings than starting them indoors.

Winter sowing also cuts out the costs associated with starting seeds indoors.  No lights or heat mats to buy, and no electricity costs.  Winter sowing is extremely cheap, and doesn’t take up space in your house.

Is Winter Sowing just for warmer gardening zones?

Nope!  I’m in zone 5b, and winter sowing has worked amazingly for me.  My little milk jugs sit out in the below freezing temps and the snow, and they grow and grow like crazy as soon as it warms up.

In fact, one of the main benefits of winter sowing for me is that the seedlings are protected from frost.  Our springs love to warm up to the 60s and 70s and then drop back to the teens.  We regularly have at least a 30 degree difference in the highs and lows for a day, so that extra protection of the milk jug allows seeds to start growing earlier than they normally would in my area, but also in a protected environment where that early growth doesn’t mean they get killed off by frost later.

Supplies needed to get started Winter Sowing

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In order to get started winter sowing, you’ll need a few supplies.  Start saving your milk jugs, because you’ll need a lot of those.

• Milk jugs – Rinse them out and dry them after they’re emptied, so they don’t get nasty inside
• High temp hot glue gun (optional) – low temp won’t melt the plastic, so it must be high temp
• Scissors – A nice, sturdy pair of scissors will make the job much easier.  I really like to use trauma shears.  The angle of the blade makes it much easier to cut the milk jugs, plus they’re very strong.
• Garden markers or Paint markers – Garden markers are UV and water resistant, making them a great choice for marking your jugs.  Paint markers can also be used.  Regular Sharpies won’t work, as they will fade off (trust me, I know this from experience)
• Potting Soil – Regular soil or garden soil won’t work, because they hold in too much moisture.  Look for potting soil that doesn’t claim to be moisture control, so it can drain well.
• Duct tape – You can use any type of duct tape.  I’ve found that packing tape tends to get brittle, so I don’t recommend it. I used Gorilla tape since it’s what I had on hand this year.  Last year I used neon pink duct tape of my daughter’s.
• Seeds – See below for what seeds to use

The best seeds for Winter Sowing

If you can grow it from seed, you can winter sow it from seed.  That said, there are seeds that are best winter sown. 

Any seeds that require cold stratification will make the perfect candidates for winter sowing.  Greens like lettuce, chard, kale, and spinach are also great for getting started with winter sowing.

But here’s the deal.  You can sow anything with winter sowing.  Last year, I even tried a watermelon as an experiment.  I started one watermelon plant inside, under lights, with a heat mat.  I started another watermelon in a milk jug outside.  In the end, the winter sown watermelon had less shock when transplanted (even though I hardened off the one from inside), and it grew bigger fruit earlier.

How to Winter Sow Seeds

And now for the step-by-step tutorial on winter sowing.

1. Make sure your milk jugs are clean.  I would also take the time to moisten your potting soil really well, and then let it drain.  This may be the only water your seeds will get for a while, so you don’t want to use dry potting soil, but you also don’t want it to be sopping wet.
2. Use a high temp glue gun to make drainage holes in the bottom of the milk jugs.  You can make holes other ways (soldering iron, nail and hammer, box knife) but I’ve found a high temp glue gun to be the easiest, fastest way.
3. Using medical shears, cut around the milk jug, leaving a “hinge” at the handle.
   
4. Bend back the top of the milk jug, so it’s open.
5. Fill the bottom of the milk jug with potting soil.  Make sure there’s at least 3 inches of potting soil, so your seedlings will have plenty of room to spread out their roots.
6. Press seeds into the soil.  With winter sowing, we typically don’t plant to the regular seed planting depth, since we’re trying to mimic natural seed growth.  For smaller seeds, sprinkle on the top of the soil and press in.  For larger seeds, you can push them in a bit, but not a deep as usual.
7. Duct tape the milk jugs shut.
8. Make sure to label them.  I suggest labeling in more than one spot, just in case the label wears off.  It is also very important that you don’t just use a Sharpie. You want something waterproof and UV proof, since these will be out in the elements.  I’ve had good luck with China markers and paint markers, but my favorite are garden markers.  I found that paint markers on the bottom of the milk jug actually lasts the longest.  Some people I know cut up old blinds, write on them with pencil, and stick the label inside the jug.
   
9. Place in an area where they won’t get blown away.  Against the house is a great spot.  I put mine in the rows between my raised garden beds.  Some people I know will put a broom handle through the milk jug handles, or tie a rope through them.  I’ve found that if they have at least 3 inches of moist potting soil, they should have the weight to stay put and not blow away, unless there’s a crazy windstorm. Leave the lid off, so moisture can get into the jug throughout the winter.
   
10. Try not to forget about them in the spring.  Winter sowing is so hands-off that it can be easy to completely forget about the seedlings you planted, in which case you might just look over one day and see a rhubarb plant that you grew from seed sticking out of the top of the milk jug! If your spring is hot and dry, you’ll need to check your jugs to see if they need watered.  It’s pretty easy to tell if they have enough moisture in them, since you’ll likely see condensation on the inside of the jug.  But you can also just lift a couple of jugs up.  If they’re very light, they need more water. 

    The easiest way to water them is by setting them in a shallow tray with water, so they can suck it up from the bottom of the jugs, but a sprinkler will work, too.
    

I hope this winter sowing tutorial has been helpful to you!  If you have any questions, feel free to drop them below, and I’ll do my best to answer your questions.

If you try winter sowing, I would love to see how it goes for you!  Tag me on Instagram or Facebook!