(Originally posted January 3, 2011; now updated and revised)
YOU MIGHT BE WONDERING WHEN, exactly, to winter-sow your perennials, annuals, herbs and veggies outdoors. The easiest answer is “now.” However, to save work later on, I find it pays to plant certain seeds ahead of others. The following schedule has worked well for me:
Perennials and Hardy Annuals. As a rule, if a plant is hardy in your zone, you can plant its seed now (regardless of the temperature outside). Sprouting will occur when warmth arrives, normally in spring. However, the seed can also sprout during some freak warm spell between weeks of frigid conditions. This is not a problem for perennials and hardy annuals. They simply yawn in the face of frost.
Tender Annuals. You can plant these early, too, with one important caveat: Should sprouting occur during a warm day (and remember, it’s even warmer inside the milk-jug greenhouse), you’ll have to throw a blanket over the container at night. For such seedlings are easily killed by frost. That’s why they’re called “tender.” Consequently, to avoid the covering-work, it pays to delay sowing the tender annuals until March or April.
Last year, in my own, zone 5-b garden, I planted perennials, annuals, herbs and vegetables using the following time-table. All of the seeds sprouted and survived (except the Delphiniums, probably because their seeds were old).
January through February:
Flowering Perennials & Hardy Annuals
Digitalis purpurea (Wild Foxglove)
Oenothera speciosa (Evening Primrose)
Consolida (Larkspur) ‘Galilee Blue Double’
Aquilegia (Columbine) ‘Alpina’ blue
Aquilegia ‘Scarlet’
Aquilegua mixed
Aconitum carmichaelii (Monkshood)
Delphinium grandiflorum ‘Blue Mirror’
Nepeta ‘Pink Dreams’ pink
Oenothera lamarkiana yellow
Alcea (Hollyhock) ‘Camois Rose’ rosy-pink
Alcea ‘Apple Blossom’ pale-pink
Berlandiera ‘Chocolate Flower’ yellow, fragrant
Aquilegia ‘Crimson’
Campanula (Bellflower) ‘Champion Pink’
Campanula latifolia ‘Brantwood’ purple
Lathyrus odoratus (Sweet Pea) fragrant
Nicotiana ‘Fragrant Cloud’ and ‘Purple Perfume’ (I also sowed these indoors, under lights; both grew with equal exuberance)
Platycodon (Balloon Flower) ‘Sentimental Blue’
Lupinus (Lupine), ‘Russell Hybrids Mix’
Centaurea cyanus (Bachelor Buttons) common blue variety
Vegetables & Herbs
Spinach
Kale
Brussels sprouts
Peas
Broccoli
Thymus serpyllum (Creeping Thyme)
Salvia (common sage)
Oregano
Cilantro
March
Tender Annuals, Vegetables & Herbs
Impatiens wallerana
Cosmos ‘Double Pink Bon-Bon’
Zinnia ‘Violet Queen’
Marigolds
Lettuce (numerous varieties)
Bok Choy
Beets
Carrots
Basil
Parsley
April
Tomatoes (I also grew tomatoes indoors under lights; I can tell you the winter-sown plants not only survived a few below-freezing nights without covering — they were stronger than the light-garden subjects, too)
Again, this planting schedule is based on my own, zone 5-b climate. If you live in a milder zone you can winter-sow your seeds much earlier than me. I know a Texan who winter-sows his tomatoes in December.
In any event, let me know if you have any questions concerning the timing of your own winter-sowing projects. Be sure to include, in your comment, which zone you are in. Meanwhile, have fun planting your garden at the “wrong” time of the year!
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Related Posts:
Winter-Sowing 101: The Basics
How to Turn a Milk Jug into a Greenhouse
My Favorite Seed-Suppliers…& Yours (2012 Edition)
Perennials Which Require Cold Stratification
A Seed I’d Winter-Sow: The Chocolate Flower (Berlandiera lyrata)
A Seed I’d Winter-Sow: The Bachelor’s Button (Centaurea cyanus)
Seeds to Winter-Sow: Platycodon ‘Sentimental Blue’
Kevin, this might sound like a stupid question, but can you winter sow corn? And if so, when? I'm in zone 6, so a little warmer than you.
Yolanda – no such thing as a stupid question around here! In zone 6, I'd wait until late March to plant corn. Choose an “early” variety, such as 'Platinum Lady', 'Quick Silver', or 'Viva.' These will germinate at lower temperatures.
Thanks for this great list Kevin! – I was wondering about growing corn this year… How much do you recommened to plant for just 2 people (and friends)? and how much space would I need for this crop?
Erin – you're welcome.
Regarding corn…after reading Michael Pollan's “Omnivore's Dilemma,” it seems there are certain Monsanto varieties which can be planted extremely close. Monsanto types are a no-no, however.
I'd winter sow 4 seeds per milk jug. Then plant the seedlings in rows 2 feet apart in the open garden.
Kevin, I'm just wondering: did all of the perennials you planted in jugs last winter bloom during summer?
Did you soak or nick your sweet peas before planting them? I seem to recall you saying somewhere that this isn't necessary with winter sowing.
Sheila – Although most perennials bloom the second year after sowing, a few bloomed for me their very first summer. These included Larkspur, Evening Primrose (both pink and yellow), Monkshood, and Nepeta. Of course all of the hardy annuals bloomed…sweet pea and nicotiana my favorites.
Andrew – Yes I did say just that in an earlier post. Neither sweet peas nor morning glories require nicking (or soaking) before winter sowing. The natural freeze-thaw cycles in winter break down their rock-hard shells.
I learn so much from you. Nicotiana is one of my favorites, too! The variety Alata to be precise. I can't find it in seed or starts. One happy year our supermarket had a garden buyer who wasn't afraid to order material other than the standard grocery store variety. That's where I first met Alata. I've asked my nurseries to order it but it's never in their catalogs. Do you know where I might find this beautiful Nicotiana? It is very tall and lacy, comes in white or pastels and has an intoxicating scent after sundown.
Andrea
Andrea – Nicotiana 'Jasmine Alata' and N. 'Fragrant Cloud' (which I grow) are, it appears, one and the same. The plant grows to about 5 feet; the tubular flowers close during the day and open at dusk; the scent is both HEAVENLY and far-reaching.
You can buy the seeds Alata online from Renee's Garden.
aaah,interesting! I've been passing up Fragrant Cloud in hopes of finding Alata! Thank you VERY much. LOVE THIS BLOG.
Andrea
Here in the UK this winter we had -17C at 1pm for days plus 2ft of snow. My Purple Sprouting Broccoli looked fine at first, but after 2 weeks of thaw, it hasn’t survived. The thick main stems have gone to mush. This is the first winter that I have lost the crop and I was so looking forward to my first taste.
On the other hand, the Arucola, whose seeds I brought back from a rainwater harvesting trip to Southern Italy, has survived magnificently and is growing back vigorously from the base. The Italians told me that it would never survive in the UK!
Here in the UK this winter we had -17C at 1pm for days plus 2ft of snow. My Purple Sprouting Broccoli looked fine at first, but after 2 weeks of thaw, it hasn’t survived. The thick main stems have gone to mush. This is the first winter that I have lost the crop and I was so looking forward to my first taste.
On the other hand, the Arucola, whose seeds I brought back from a rainwater harvesting trip to Southern Italy, has survived magnificently and is growing back vigorously from the base. The Italians told me that it would never survive in the UK!
Welcome, Sustainable rainwater harvesting – Yes, you've had rather severe weather in the UK! Amazing that Arucola (we call it Arugula here) survived such low temps for you. Some salad greens are really very sturdy.
Would you believe it is presently -12F (-24C) here? Thankfully none of my winter-sown seeds have sprouted yet!
Hi Kevin,
Just discovered your blog last evening when googling how to winter-sow corn. You have some great stuff here. Thanks!!!
I am in zone 6a, just a tad south of you, and I'm wondering how tall my corn seedlings might be 3-4 weeks from now if I sow them in milk jugs and place them outside today. I'm trying to time corn, squash/melon, and beans for a 3 Sisters patch. I think it would be advantageous if I could start the corn so that it's 4-6 inches tall BY last frost date (mid-May here), so I can transplant them then. I'd then immediately direct seed my pole beans and winter squash, as well as my melon seedlings (which I will start inside on May 1). I'm concerned that if I direct seed the corn after the last frost, I'll be losing to much time with my melon and winter squash and they might not mature in time.
Any thoughts? This is my first experience with sweet corn.
Sarah D – nice to meet you! I've wanted to try the three-sisters approach to gardening for a long time. Seems you need considerable space to pull it off, however. Here, I grow melons and winter squash vertically.
Corn germinates very quickly when soil temperature is 50 degrees/daytime. Consequently, I think you are better off direct sowing it. Then proceed, as you mentioned, to direct-sow both pole beans and winter squash once the corn achieves 4 inches in height. You are wise to start your melons early indoors, since they demand such a long, hot growing season.
Hope you'll visit here frequently — I'd love to hear how this project works out for you!
Thanks for your ideas, Kevin. Nice to meet you too! I have a 10' by 22' space for the three sisters scheme. I hear it can be pretty unruly, but I'm intrigued by the whole companion planting idea, so I'm going to jump in and try it. Thanks for helping me bounce this around in my head. Do I have to wait until the “no chance of frost” date to direct seed the corn or can I do that sometime between now and then (say May 1)?
I've winter-sown my tomatoes this year and have many tiny seedlings that are JUST beginning to get a set of true leaves. I'm trying to keep the faith and believe that I will have sturdy plants at some point that will produce plenty of tomatoes.
I'll be watching the forecast for heavy frosts as you suggested.
Just planted out some lettuce and kale seedlings (also winter-sown) and placed row covers. I'm pretty sure they'll all do well. Also transplanted some tiny onion seedling that I winter-sowed. Have no idea how they will fare. For me, winter-sowing is perfect because my home is too cool to start seedling indoors and the whole light and bottom heat thing just gets terribly complicated.
Anyway, thanks again.
Hi, I live in UK Zone9 and am wondering if outdoor winter sowing in plastic bottles, would work the same here?
Many thanks for your blog, please keep up the good work.
Audrey – Nice to “meet” you. Yes, you can absolutely winter-sow where you are. What do you plan to plant?
Hi Kevin, I’m wondering about geraniums. I’m in zone 5 and wondering timing to have them survive the cold but be large enough for planting in containers by the end of May.
Barb – If you are referring to the large-flowered, zonal geraniums (pelargoniums), you can winter-sow them now. However, they won’t germinate until the soil temperature in your container reaches 70 degrees, and stays there fairly consistently. But the seedlings can handle night time temperatures down to 29F. They are amazingly sturdy plants.
Another thing. Try to sow your zonal geranium seeds thinly, meaning not more than 9 seeds per gallon-size container. This will give the young plants room to grow.
I love your site!! Can’t wait to start the winter sowing- got my gallon jugs all ready!
You asked for a Wassail recipe. Here’s one I like:
14 very small (Lady) apples
3 12-oz bottles of good non-alcoholic beer ( I like Bitburger alcohol free, or Erdinger Alkoholfrei. I get mine at a German specialty store.)
1/2 c firmly packed brown sugar
2 3-inch pieces stick cinnamon
1 tsp whole cloves
1/2 tsp ground ginger
3-4 whole allspice berries
1 4-inch strip of orange zest (no white membrane)
2 c apple cider
Bake the apples in a shallow pan at 375 degrees until tender, about 20 minutes. You need not core them or peel them.
Heat 1 bottle of beer in a large saucepan with the sugar, the spices, and the orange zest and simmer for 10 minutes.
Add the remaining bottles of beer and cider gradually.
Bring to a boil, then lower the heat and simmer for 5 minutes.
Put half of the baked apples in a large punchbowl and pour the wassail over them.
Use the rest for a floating garnish on top.
Drink warm.
If you want a “grown-up” version, use ale in place of the NA beer and sherry in place of the cider.
Please let me know what you think!
Stacey – Glad you like this place, and glad you sent in this Wassail recipe. I’ll copy this into my recipe folder, and will surely make it next December, when the carolers come a-wassailing!
Have fun winter-sowing…I’ve just now planted 6 jugs, but have many, many more to do. What fun!
I’m so excited about winter-sowing! I’m looking into perennials that require full to partial shade, does this matter with the winter-sowing? I didn’t check everything on your list, but it seemed that most of the plants were “sun” plants. Thank you!
PERFECT! Your advice is always perfect…
Jenny – So glad to hear that you are winter-sowing! Even if your perennials (or annuals) will ultimately require partial to full shade, you still winter-sow them in the usual manner: in full sun. Sunlight in winter and early spring is too weak to have any negative effect on the emerging seedlings.
ArtistryFarm – Well, if not perfect, then timely!
I made my mini-greenhouses tonight. I don’t have a gas stove for heating up the screwdriver to make the drainage holes, but I found a candle flame worked fine. This was so easy! I even let my boys poke some of the holes (w/ close supervision, of course) which they enjoyed immensely. We are going to start some seeds tomorrow. I usually soak my parsley seeds, but am thinking I can skip that step after reading your explanation of the freeze-thaw cycle. This is so exciting!!!! True gardening in Winter!
I just caught that parsley is listed on the March schedule.
Very helpful list! I have taken more of a free spirit approach and sowed with abandon this year – reserving only the tenderest of plants for later planting. At my house, you have to be tough to survive! I read the comments about corn with interest, because I plan to grow some ornamental corn this year – mostly for decorating in fall. My husband has absolutely forbidden me to buy foddershocks! (Apparently, he had to vacuum his vehicle for hours after the last time I brought some home….wasn’t that clever of me to use his vehicle?)
badger gardener – Drainage-hole-melting — what a fun way to get your kids involved in gardening! Fun, too, could be an experiment with parsley seeds: sow some in January, sans soaking, and others in March, pre-soaked. Then you can report your findings!
Kelli – You are a winter-sower after my own heart.
Wow, thanks, Kevin,
I live in the Pacific Northwest and we just got clobbered! Once we crawl out of the remaining tree limbs, power lines from my house to the road, etc., cant wait to get restarted with the ws you inspired me to give a try. after the last 3 days w/o any power we have just begun to feel the heat and electrics again this morning! (&email and cable). what a winter blast for us wimpy washingtonians. Cant wait to get going with your suggestions as well as try some tubs of fava beans and pea tips for salads. Let me thank you again, love your resourcefulness and generous sharing of knowledge and experience as well as ability to dumb it down to my level. Your the best! I will spread the word to my limited number of garden geek friends who will also appreciate your simple communication style!
I’ve been drinking milk all winter to have my gallon containers ready for seeding. As I live a town away from Kevin, it’s wonderful to be in the same zone and ready to follow his instructions. Corn flowers or Bachelor Buttons are a favorite and I’ve had overwhelming good luck getting an early start in my garden with these fabulous blooms. I’m ready to start my garden in this Year of the Dragon. Thank you, Kevin
Today I am going to start winter sewing. Have a 3 dozen cleaned out containers to start with, and am excited to read that this is something you can do throughout the winter depending on the type of seed.
I’ve picked up 30 packets of seeds – way too many, I know, but I’m also planning on gifting some. Most packets have way more seeds than I anticipate using – any suggestions?
I purchased soil that is especially prepared for starting seeds – is this the proper kind or would regular potting soil be better?
I appreciate your informative newsletter and the helpful responses from your readers. So exciting!
Sharon – Yes, your region really got clobbered last week! Glad to hear that your power and heat have both been restored. And thank you for your kind works. I can’t tell you how much I appreciate you sharing this site with your garden-geek friends. I think gardeners — and people who feed birds — are the best people on earth.
Incidentally, I’m a native Washingtonian. Born at Sacred Heart Hospital in Spokane.
Anne – Well, that explains why, when I visited our local supermarket last Wednesday, there were no gallon-size milk jugs to be had!
Deborah – Three dozen jugs — good for you! Honestly, we who winter-sow usually end up with waaaay more plants than we can possibly use in our own gardens. Good idea to gift some of your surplus — I do that, too.
You asked about soil. When winter-sowing, use any mixture which is well-draining. It need not be sterile, since we are planting outdoors, not in. Over the years I’ve tested seed-starting mix, all-purpose potting mix, African-violet mix, and my own compost, amended with perlite. All these worked admirably for winter-sowing.
I… I should just print out this page. It would be easier to recall it that way – heehee!
I am ready to do my winter sowing tonight… I have six milk jugs cleaned and ready! I even took a step forward and picked up some vermiculite! I’m going to make a mixture of vermiculite, coconut coir, leftover “seed starting mix”, and garden soil for my containers… I hope that’ll work great!
Sadly I’m not like Deborah up there, goodness! What I could do with that many to start seeds! Is it possible to make quadrants in the containers? Pair up seedlings with similar requirements and make the most of my limited space?
Donna – Six jugs is a great start! I wouldn’t divide different seeds into one container. What looks like a lot of room to you now will not appear so when the seedlings emerge.
Although I happen to prefer gallon-size jugs for winter-sowing, in the past I have also used soda-pop bottles made of clear plastic. As with jugs, punch out plentiful drainage holes in these, too, and cut the center to permit a hinged top. Be sure to remove the lid! Such bottles are great for sowing small quantities of seeds.
I put out my little greenhouses yesterday and they are already being exposed to freeze-thaw. Started in the teens, then came freezing fog (I didn’t know that was possible) and now we are in the 40′s, with temps. dropping later and rain turning to snow. My kids enjoyed this so much that I am going ot talk to the teachers about doing this project at school. We installed a school garden last year (I say “we” liberally because my friend and fellow parent did all the planning and grant-writing, I just provided some labor) and w/ the $ we did purchase a few grow lights. However not nearly enough for all of the classrooms. I don’t know how the teacher will feel about first graders and hot screwdrivers but am hoping if we get some more volunteers for supervising, she’ll let them do that part too.
badger gardener – Yes! Seems like you’re having a good influence on a number of kids lives. I hope the school sees the value in all this. Winter-sowing (and growing plants in general) is a biology lesson in itself. Not to mention it’s hands-on…and consequently FUN.
Thanks, Kevin – this is so helpful and informative! I’m in zone 7a here in Brooklyn, NY. I have more seeds than containers right now, but a friend just took me on a “tour” of her apartment building’s recycling room where I scored many gallon milk jugs and other suitable plastic containers – ha!
Now I’ve just got to get a planting medium. I’ve read that some people use seed-starting mix, others use a potting mix like ProMix, and others mix these two together. Some folks even used their own soil / compost blend and baked it in the oven or poured boiling water over to kill weed seeds and soil-borne nasties! That sounds like a bit too much work for me…I’d rather go the sterilized mix route. Do you have a blend you like to use for winter sowing?
Aimee — congratulations on your big recycling score!
Concerning soil: You can use a sterilized mix if you want to you, but this certainly isn’t necessary. After all, the jugs are being placed outdoors where there is little danger of “damping off.” Damping-off is a fungus that typically strikes seedlings which are grown in non-sterile soil…indoors.
Over the years I’ve tested all kinds of mixtures for winter-sowing projects — seed-starting mix, all-purpose peat/perlite potting mix, potting mix with “moisture crystals,” African violet mix, and my own compost, amended with perlite. All of them worked perfectly well.
The only winter-sowing-soil requirement is that the mix be very well draining. And all commercial mixtures — which are usually composed of peat & perlite — fit this drainage-requirement admirably. Just make sure you punch out lots and lots of drainage holes in your containers. And have FUN!
How many holes do you generally “drill” in a milk jug?
Carlie – I drill (or rather, melt!) 12 holes in the bottom (3 in each quadrant), and then 2-3 holes along each side, about a half-inch up from the bottom. You can see close-up shots of both the bottom and side drainage holes in this post.
And here are more details for turning a milk jug into a greenhouse.
Let me know if any other questions arise — I’m happy to help.
This idea intrigues me and I’m going to try it. I think I live in the same general region as you, I’m in the northern Dutchess county area, right on the border of zones 6-5A. One question, you mention sowing beets and carrots…do you find you have any trouble with the root vegetables when you transplant them? I’ve always heard that carrot seedlings don’t tolerate being transplanted well, that it leads to root deformities.
Hello, Kevin. What type of soil should I use in my gallon jugs? Zone 5, Alabama.
Denise – I’m a wee bit north of you, but I’ll still say “Howdy, neighbor!”
Surprisingly, carrots can be transplanted early on without worry of root deformity. I know that some winter-sowers will plant the seeds in a cell pack (one seed per cell), and then place the pack inside a jug. This way the young carrots can be transplanted with minimal root-disturbance. I’ve found that unshapely carrots are more often the result of rocks in the garden bed, or compacted soil.
Ditto for beets. Although beets sprout so readily in zones 5 and 6 that I doubt one gains anything by winter-sowing the seeds.
Sharon – Over the years I’ve tested all kinds of mixtures for winter-sowing projects, including seed-starting mix, all-purpose peat/perlite potting mix, potting mix with “moisture crystals,” African violet mix, and my own compost, amended with perlite. I can tell you that all of these worked perfectly well.
The only winter-sowing-soil requirement is that the mix be very well draining. And all commercial mixtures — which are usually composed of peat & perlite — fit this drainage-requirement admirably. Just make sure you punch out lots and lots of drainage holes in your containers!
Howdy, Neighbor!
I was indeed thinking that it probably wasn’t worth sowing the beets this way, but I am very intrigued with your winter sowing ideas in general and spent the day checking out which containers I have that would be good for this project. I like that idea of planting one carrot seed per cell… I tend to hate weeding out the carrot seedlings. So this is something I’m definitely going to try, too.
Between your column and the new Fedco seed catalog, I’m itching to get gardening!
Denise
Denise – Agreed — thinning out thickly-sown carrot seedlings in the open garden is a royal pain! All that bending…and all those wasted seeds!
With a cell-pack, even if you sow 3 seeds per cell, it’s easy enough to pinch off (and thus kill) all but the strongest seedling.
Itching to get gardening here, too. Thank heavens for winter-sowing!
Hi,
Just wanted to say thank you for the winter sowing information! I shared your link on our garden blog, hoping to get our gardeners growing this weekend. Great information, thanks! -Amy
Amy – You’re welcome. Have fun!
Quick question about winter sowing, Kevin. Just how many seeds is it reasonable to put into 1 jug? I started some artichokes last week and only put 2 seeds per jug. But, I’m wondering if I’m being too conservative?
Thanks so much for your tips. We’re really looking forward to our garden this year!
Michelle Ann Anderson – Nice to meet you. With large seeds (spinach, broccoli, etc.), I usually plant six to nine per gallon-size jug.
I try to sow tiny, dust-like seeds (nicotiana, thyme, etc.) as thinly as I can. Which isn’t in fact very thinly at all!
But winter-sown seedlings are incredibly strong. If you have to slice them up like brownies at transplanting time, so be it. They will recover from the ordeal very rapidly.