I’ll admit it. I’m a gambling man. Many gardeners begin cleaning out their garden right after the first frost. While they know that many species in the garden can handle light frosts, many like to go ahead and harvest whatever produce remains, and clean up the garden before a really hard frost kills everything.

But I like to push our garden’s limits, because many of the fall and winter vegetables left growing in the garden get sweeter and sweeter as the days get colder and colder, and shorter and shorter. As long as there isn’t a killing frost, the garden just gets better and better. That which doesn’t kill us makes us sweeter, so to speak. So why does this happen?

Many of the plants from the Brassicaceae family –  including brussels sprouts, turnips, broccoli, cabbage, cauliflower and rutabaga – survive the downturn in temperatures by turning some of their stored starches into soluble sugars. This helps prevent the liquid in the leaves from freezing (think of how sugary liquids don’t fully freeze in your freezer). And since the plant sap doesn’t freeze, it doesn’t expand. And since the sap doesn’t expand, it doesn’t rupture cell walls. Which prevents plant stems from turning into limp spaghetti noodles.

So as the plants catch a chill, they fill up with sugar. Which, when it comes to slightly bitter veggies like brocolli, brussels sprouts and collards, is a delightful thing.

But I’ve noticed another quirk that happens to many plants left in the garden through the first several frosts. They turn purple. Which is also a delightful thing when the rest of the landscape looks brown and barren. After a little research, I’ve learned that the change – like most plant changes – can be traced back to photosynthesis. Remembering back to high school, you’ll recall that photosynthesis uses sunlight and carbon dioxide to create glucose (a sugar) that is used to help the plant grow. They do this with the help of chlorophyll. – a chemical that turns the plant green.

But shorter days means less sunlight. Which means less photosynthesis. Which means the plant starts shutting down. Which means the chlorophyll goes away. Which means less green. The same pigment that makes purple cabbages purple is present all season long even in the green-colored Brassicaceae species. But it’s invisible until the green chlorophyll fades.

So. There’s our little cold-weather garden lesson. You don’t really have to understand it in order to enjoy both the taste and the prettiness. But winter’s coming. You may as well settle into reading about gardening rather than doing it.

Click on any of the below pictures to start a slideshow, and share with us the things you find in your late season garden in the comment section.

by Josh Kilmer-Purcell

Reader Comments

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You certainly have a bountiful, beautiful, neat, cared-for garden. I love all the tidy raised beds . Thats how I will do mine some day.

Andy Kremer

Great post, and very informative. Just saw your show for the first time today and thought it was great.

Tree leaves work the same way – they're always bright yellow and orange and red, but the chlorophyll hides it. I just learned that a few weeks ago. Learning so much these days!

Phillip Collette

Also: I love the show and I'm a little jealous of all your land. I would love to come and garden with you guys at some point in the future. 🙂

Phillip Collette

There is more to the purple and green thing than meets the eye. I remember from my own biology degree that there are many different plant pigments that serve various purposes by making use of different wavelengths of the electromagnetic spectrum. Among these pigments are the chlorophylls (a,b etc), anthocyanins, and the carotenoids. The chlorophylls and carotenoids are the pigments that are inside the chloroplasts that are harvesting the light energy. The chlorophylls are the green pigments and are in constant breakdown and replenishment. When many plants are transitioning into dormancy they stop replenishing the chlorophyll for various reasons. The carotenoids that are less destructible, longer lasting, and responsible for the yellow color are kept around in many plants because they can keep doing their jobs without needing to be remade over and over. Anyway, anthocyanins make those red and purple colors that you noted and serve different purposes of their own. Scientists know that they are responsible for protecting plant DNA from UV damage and they also offload some of the energy from the changing chloroplasts to prevent photoinhibition. The anthocyanin pigment production is increased by the increased presence of the sugars you were talking about and, not coincidentally, these molecules have a sugar group bound to them.

The unmasking of the other pigments by the destruction of the chlorophyl is true for both the carotenoids (yellow) and the anthocyanins (red/purple). The anthocyanins also receive a humongous boost to their population when the temperatures drop [in plants that are inclined to make excess quantities of them]. This is the other factor that contributes in making certain plants (and fruits) such vibrant shades of red and purple.

I had to refresh myself on a little of this via the internet (nobody's perfect ;), but I hope this helps to make the subject even clearer.

To summarize: Anthocyanins are responsible for those wonderful purple and red colors. Their populations additionally skyrocket by all of that sugar that you were talking about [in addition to their spring/summer presence]. And they have many helpful benefits for the plants that can make these pigments in large quantities. ( They are very healthy for us too)

BTW: I am starting my own garden blog called "A Garden Less Common" (via google) if you care to follow along. I am just getting started, but I hope that it will be a good endeavor.



Stephen Paris

I was wondering where I can get the latest updates on the farm and happenings? I have tried to find it on your website. Maybe I just have missed it. I hope all is well. Take Care


Dr. Brent

Hi, Stephen

This website is updated almost daily with new content. You can also sign up for our monthly email newsletter (see info for signing up on the homepage). Otherwise, the best way to stay up-to-date is to "like" our Facebook page, beekman1802boys

Katanna Usrey

I ordered my first wheel of cheese today! I am looking forward to another package arriving from Beekman 1802!! I just love everything Beekman. My dream is to come Sharon Springs one day soon and see you and Brent!!! So many people around the world just love guys and what you have done and what you stand for !


Sonii Nagel

I garden year round in Central Texas. This year has been extremely mild. Winter gardening is more fun for me than the hot summers and I do mean HOT ! 90 days of over 100 last year and a drought with NO rain during that time.

My brussel sprouts are just coming along and I am wishing for a few more freezing nights to get them sweeter.

Roasted brussel sprouts are delicious. Don't ever boil them please !

Lisa Evans

Josh, I picked up "The Bucolic Plague" on Friday and have already finished it!! It was the funniest book I have ever read, and I loooooved getting some history on you, Brent and the Beekman. I have been watching your show since the first season and keep looking for the next one. Please tell me there is another season in the works!!!!

Neville Morrison

Love the pics,great blog post . In my garden down here in va my Georgia collard greens can last all winter

I'm like you I leave stuff in the garden till its covered in snow and ice


Thank you Josh. It's been fun watching the Swiss Chard keep plugging away with an array of winter colors. Never really made the connection between the way brassica survive winter and the conversion of starches to sugars, but it makes good sense. Matt.


Just discovered your blog! We garden year round here- we are in NC so our winters aren't as rough but we find that our collards are so much better (sweeter) after a good frost!

Linda Finch

Hello Josh and Brent;

I just heard a (hopefully) rumor about your next season on tv.

Will the "Beekman Boys" be back? Please tell me I heard wrong!

Love all of you and so enjoy seeing you weekly!

mary smith

just as your gardening season is winding down mine is just starting here in florida, it has been a bit hot this year so lettuce is going to seed faster, but tomatoes & bell peppers are doing great!If you get a minute send some cool air this way.thanks for more than a few laughs & great tips for garden.

Edward Brewer Jr

My husband and I love to leave our Kale out until it gets its first frost. The Kale taste so much sweeter then and it makes the most excellent Utica Greens 🙂


I just put up my first attempt at green tomato chutney. It's spicy, interesting…might do it differently next year. Any suggestions?


Julia Shepherd

Just pulled my second batch of homemade saurkraut out of the closet and am getting ready to can. Soooooo much better than stuff from the grocery. Home gardening has special rewards.

caroll zerkle

Hi We garden year round– our winter garden is up– we use haybales & plastic will exchange with anyone who wishes to learn how. I canned 110 jars of cherries this past summer plus other stuff. Will exchange recipes on canning, or how to information. Great garden Caroll in Southern Nevada

Beth DiGesu

I love the pictures. I love gardening and I also planted kohlrabi for the first time this year…….I LOVED IT!!!!

Jack Sica

I love the pictures and the artical. You sounded alittle like Alton Brown but that's not a bad thing. Thanks for explaining the what's and why's of the garden these days. I learned a few things.

Linda Schoener

Love the pictures! And your gardens make me hungry for the veggies that have long expired in my garden. I did the Lasagna gardening this year with great results…the layering of the soil/leaves/manure proved to be the trick up here in Michigan….my beets were wonderful, and the tomatoes grew like magic. I can't wait till the winter is over to start planting again…right now my parsley and sage are still pickable, so is the rosemary, but soon she will die as she doesn't overwinter well here in a zone 5….so sad! Don't ya just love gardening,it gives us something to look forward to as we comb the pages of the gardening catalog's that are now arriving in my mailbox each week…..stay warm and cozy this winter boys, and dream of an early spring :o)


Our kale always tastes best after a few frosts! (Your heading says a Color Puple..you left out the “R” like Massachusettes residents 😉 I was one of those once 😉

Vicky Trice

I loved the photos!!! Wisconsin has had a hard frost but I am still able to pick fresh parsley for soup and sage for roasted chicken. I clean up the garden and lay down hay after the first heavy frost,but November was very mild here. I may even be able to pick some other herbs before the first snow:)

teresa powers

Are these things in your garden right now? We live near Cooperstown and stil have a few things. Wondering how to keep our garden going longer.

By the way, we stopped at the store today to drop off books to be signed and really enjoyed the windows! We missed the book signing at the Otesaga.


Susie Milligan

Love your pictures and … this is a great article about the sugars in vegetables. Learned something new today.

The carrots are still in my tiny garden and I cover them and use them fresh or cooked all winter. Will plant beets and turnips next year to winter over. Thanks, Josh

Tammy Wolford

Thanks Josh. I love how you make learning more about the garden so much fun. Beautiful pictures. I'm crushing on your brussells sprouts 🙂

Rose Marie Trapani

I always plant a fall garden in August. Cold hardy veggies. I still have great arugula. I cooked the last cabbage today! I love going out and digging after a snow and finding frozen parsley.

sue tolbert

Very nice science lesson, Josh. I did plant a number of ornamental cabbage this year because I love watching them turn different shades of purple during the growing season. I was so happy with how large they grew and had big plans to use them during Thanksgiving weekend. (you know how wonderful Marthas fall arranging is) well, my two dogs decided they would eat up the cabbage and I could figure something different as far as my arranging went! sue t.

Karen Russo

I don't have a veggie garden because the deer here in NJ are a problem. I do have three beautiful ornamental grasses that go from green to a rusty brown in the fall with beautiful plumes on top. Our landscaper always asks if we want to cut them down for the season, but they look beautiful in the snow!

Denise Coard

These pics are wonderful and inspiring for my next fall/winter crop! I absolutely love the physique of the brussel sprouts!!! We don't eat a lot of them….but there appearance in the garden is too inspiring not to plant!!! Lovin the leeks too!!! Thanks for sharing!