Unseasonably warm weather can put a damper on your winter sowing season. Every time we have a mild winter, I get tons of people asking me what to do.
So, I thought I would write a post to share all of my tips, and show you different things you can do to prevent premature germination.
Do I Need To Worry If We Have A Warm Spell?
For the most part, you shouldn’t have to worry. If the mild temperatures only last for a few days, then your seeds probably won’t germinate – especially if they are covered by snow.
If it’s more like an early spring than a mid-winter warmup, then you also shouldn’t be too concerned. As long as you use the right types of seeds for winter sowing, they will survive early germination just fine.
However, if it’s during the early or middle part of winter, and there is no snow, then you should definitely follow my tips below to prevent premature germination.
Related Post: Winter Sowing Seeds: A Quick-Start Guide
How To Prevent Winter Sown Seeds From Germinating Early
Though you can’t fully control germination, there are several things you can do to prevent your winter sown seeds from sprouting too early during a mild winter. Try these tips:
- Start later: Wait to start sowing until later in the winter. Here in Minnesota zone 4b, I usually start in mid-January. During a mild winter, I will wait a few weeks longer, depending on the weather forecast.
Related Post: When To Start Winter Sowing Your Seeds
- Shade your containers: Put your containers into the full shade. If the sun doesn’t hit them, they should stay cold enough to prevent germination.
- Insulate your containers: Cover your containers with snow whenever you can. This will help to block the sun and act as an insulator to keep the soil cold. As long as they stay cold, your seeds will be fine.
- Protect the seedlings: If any of your seeds have germinated, and the weather forecast calls for freezing temperatures, then you could either cover the containers with a blanket, or move them inside until the freezing spell passes.
- Save some of your seeds: I always save a few seeds until spring just in case something goes wrong with my winter sowing. It’s a good habit to get into.
Winter sown seeds can germinate prematurely during a mild winter. But, as long as you take steps to protect them, and keep them cold, then you don’t have to worry.
For more tips about caring for your spring containers, check out my winter sowing FAQs page.
If you’d like to learn how to winter sow, then my Winter Sowing eBook would be perfect for you. It’s got all the information and step-by-step instructions you need to be successful. Download your copy today!
Otherwise, if you’re ready to take it to the next level, and learn how to grow any type of seed you want, then you should take my Seed Starting Course. This fun online course is totally self-paced, and will teach you how to become an expert. Enroll and get started today!
More About Winter Sowing
- Winter Sowing Containers: What Works & What Doesn’t
- Choosing The Best Soil For Winter Sowing
- How To Clean Winter Sowing Containers For Reuse
- How To Prepare Containers For Winter Sowing
Share your tips for winter sowing during a mild winter in the comments below.
Sunray says
Good luck on your winter sowing everyone. I put my containers out in December. Need to check them out since the snow is melting.
~Cher
Amy Andrychowicz says
Wow, December? You are on the ball! I usually make myself wait until early February. This year I feel a little behind on my winter sowing, but I think it’s just because of this unusually warm winter we’re having. Hope the warm weather doesn’t cause your ws seeds to germinate too early.
Kirstie says
The weather has been so warm here in Western NY! I think we skipped most of winter! I have 54 containers that I have winter sowed and as of this week I have 8 that have sprouts. Because of the warm weather, I am planting some seeds in pots without lids and if it gets too nippy then I just pop them in the mini greenhouse for the night. The one downside to this beautiful spring is we have not had much rain so I have had to keep an eye on my containers to make sure they don’t dry out!
Amy Andrychowicz says
Yep, same here in MN. It feels like June and it’s only mid-March! It’s awesome! But it’s been really dry here as well, so I’ve been hand watering my winter sown containers too.
homeblessings says
I’m in zone 7a and it has been a super warm winter. I’ve stopped winter sowing for a little bit because everything is already sprouting. But I’m betting on the nice weather continuing, and I’ll start again once I see what happens. If not, I’ll try to protect my seedlings the best I can.
Amy Andrychowicz says
In zone 7a, I’m guessing your winter sown seedlings will be just fine. Good luck!
homeblessings says
I’ve only done two more containers, and I think they will be my last as it’s in the mid 80s here in March in zone 7a. I have to keep watering mine too. Most have sprouted already.
I don’t think this was a good winter sowing year for me. I started too late for all the warm weather this Feb and March. Next year I’ll start in Jan.
Amy Andrychowicz says
Wow, mid-80s in March!?! That’s amazing! You can probably start planting your seedlings into the ground. Yep, this winter has been very warm for all of us. Here in MN, March is usually our snowiest month. It feel like June here last weekend. I love it! Hopefully you’ll figure out the right timing for winter sowing in your zone next year!
Gardener Lisa says
Amy,
I’m in 7b, and this February has been warmer than usual – but I have faith in the seeds/sprouts and this awesome ws-ing technique. Thanks for your tips to keep them from prematurely sprouting!
Amy Andrychowicz says
You’re welcome! Hope your winter sown seeds will wait until the right time to sprout, and that the unseasonably warm weather won’t throw them off!
Annie says
We’re well into into Feb and still having yo-yo weather. Some days it can be 5c above some days -20c, and it’s been like this all winter. I’m going to put some of the seeds outside and keep them covered in snow and see what happens, but I’ll keep backup seeds indoors just in case.
Amy Andrychowicz says
That is always the smart way to do it. Mild winter temps can definitely sometimes confuse winter sown seeds into premature germination. Keeping the containers covered with snow will definitely help! Good luck!
Marie says
I live in the Pacific Northwest and on the water (protected from winds) so the microclimate can be 4-5 degrees warmer than 2 miles inland. We have had a lot of snow and more freezing nights without rain this year. However we also have had our usual warm days of 60 and nights of 40 with inches of rain mixed right in as well.
Cold stratification looks necessary for me but for how many days?
When do you recommend starting annuals and tender annuals?
What do I do to keep them from drowning? I am using 4 holes per quadrant but this is my first time winter sowing and I’m not sure if that’s too few or too many holes. I’ve considered using a lid with 4-5 holes but I’m concerned that will be too much of a greenhouse effect.
Some of my seeds are on the rare side, and imported, like a walking stick cabbage. They grow these in the Guernsey Isles in the English Channel so it’s probably ok but I’m keen to hear your thoughts on some of others.
Amy Andrychowicz says
Hi Marie, if you’re new to winter sowing, I would definitely recommend that you keep some of your seeds so that you can still start them using a different method if winter sowing doesn’t work for them. Especially if you’re using rare seeds.
As for the holes in the containers, you can always add more holes if you find that they aren’t draining quick enough. Here’s a post that will give you more details about how to prepare your containers… How To Prepare Containers For Winter Sowing
And this post will give you even more info that’s great for beginners… Winter Sowing – A Step By Step Guide
Marie says
Thank you Amy! Could you give me the ISBN for your Winter Sowing ebook. I want to request it for my local library.
Amy Andrychowicz says
You’re welcome! It’s only available as an eBook for sale on my site for now, there’s no hardcover version currently available. So, no ISBN number. Thanks for asking though! I will have to figure out how I can make it available as a hard copy book one of these days. 🙂 Here’s the link to purchase and download it… Winter Sowing eBook.
Marie says
Thanks so much, can’t wait to read it!
Amy Andrychowicz says
You’re welcome!
Tommy says
Ive had to prechill a lot of seed that I normally would have just wintersown because of the up and down temps,I was afraid that some of mine that call for 90 to 120 days of 40 degree temps wouldnt get it,I'm glad I did,very strange winter..74 degrees today
Amy Andrychowicz says
Good call on pre-chilling your seeds! Wow, 74 degrees in February! Unreal. Yes, it has been such a weird winter for us too. Warmer than usual temps, and hardly any snow.
Amy Benham says
Can you tell me why we should not use the soil out of the yard? I usually use a little of the worm compost and then some of the "better" clay in the yard.
Amy - Get Busy Gardening says
Amy – Potting soil has been sterilized to remove disease and pests, so it's clean. Garden soil and compost are not sterile, so the chance of disease or pests killing your seeds/seedlings is much higher. If you want to use compost, you need to sterilize it first. Also, garden soil is generally too heavy for starting seeds. It's worth spending a few extra dollars on potting soil
Monica says
I’m in a cooler zone, 6a (formerly 5b) and I’m not too worried about this mild winter we’re having. I’ve had a few sprouts every year when we’ve gotten a spell of cold overnight weather and I just cover the containers with their lids (and sometimes a blanket depending on how long it’s been warm and how cold the night gets). Most things that come up early when there’s still a chance of frost can handle the cooler temps.
I usually wait until middle-end of Feb to winter sow annuals and veggies, so that’s on schedule. I did sow natives and things that require either stratification or scarification on 12/31 and none has sprouted yet.
Amy Andrychowicz says
Awesome, thanks for your input and added tips! Last year, I lost a bunch of zinnia seedlings because they germinated too early. I had tons of seeds so I wasn’t worried. I wanted to experiment with them anyway, to see how they handled the cold and winter sowing. Now I know and I’ll start them much later this year! 🙂 Everything else has been totally fine for me too.
The Mitchell Family says
can you winter sow in zone 8? We never get snow and only occasionally get frost. Should I be planting a 2nd crop rather than even worrying about this?
Amy Andrychowicz says
Yes! You can winter sow in any zone. Using containers to start your seeds, rather than direct sowing them gives them added protection from the elements and pests, and any freezing temps you may have. I use this method during the summer to start my fall crops.
Although if you have seeds that need cold stratification, you would need to give them a cooling period before winter sowing them in your zone – the benefit of colder zones is not having to do that. Also, your seeds will sprout much sooner than ours will in colder zones.