Fall and Winter Vegetable Gardening

They Do It in Provence

Across the Atlantic Ocean areas throughout the Mediterranean region of southern France and northern Italy, gardeners are preparing vegetable beds and buying fresh seed in anticipation of planting their fall and winter vegetable gardens. From the 45 parallel N. latitude on down, for centuries, European gardeners have enjoyed cool season vegetables throughout the fall and winter months.

U. S. gardeners, too, can enjoy their own home-grown cool season vegetables direct from their gardens during the fall and winter months, without the aid of a greenhouse. In southern areas, the combination of a row cover with a poly tunnel is all that's needed to grow lettuces, kale, chard, spinach, radishes, cilantro, turnips, beets, onions, mache, bok choy, broccoli raab and more.

You might think, but their weather is moderated by either the Gulf Stream or the Mediterranean Sea, quite unlike the volatile winter weather on the North American continent. Yes, that's certainly true. And besides, we don't have enough sunlight to grow crops in the winter, one might add.

As far sunlight and day length, Avignon, Provence (at 43º 29'N) has less day length during the fall and winter months than Amarillo, TX (35º 13' N).

Month

Avignon, Provence*

Amarillo, Texas**

08/31/13

13 hours, 14 minutes

12 hours, 58 minutes

09/30/13

11 hours, 45 minutes

11 hours, 52 minutes

10/31/13

10 hours, 15 minutes

10 hours, 47 minutes

11/30/13

9 hours, 9 minutes

9 hours, 59 minutes

12/13/13

8 hours, 57 minutes

9 hours, 49 minutes

01/31/14

9 hours, 51 minutes

10 hours, 26 minutes

02/28/14

11 hours, 9 minutes

11 hours, 22 minutes

*Daylength, Avignon France http://dateandtime.info/citysunrisesunset.php?id=3035681&month=11&year=2013                                                                                                                                      **Day length Amarillo, TX http://www.sunrisesunset.com/calendar.asp

We, and others, are able to grow and harvest deep into the fall and winter when the temperatures plunge for a few simple reasons. Planting and growing is begun while the air and soil temperatures are warm and day-length is longer in September, October and November than in December and January. The heat of summer is over, allowing cool season crops to germinate and grow. What is required once cold, snow and sometimes ice descends is protection against these damaging elements. Row covers and poly tunnels placed over the crops is all that's needed. They need not be tightly tucked in or airtight. It's OK if some cold air reaches the crops, in fact, some circulation is good. A greenhouse, whether inexpensive or heated, is not required.

Initially, after seeding, my practice has been to place a lightweight row cover, usually a spun fleece sometimes called a frost blanket, over the rows. The row covers provide protection from wind, heavy showers, insects, desiccating sunlight and birds. As nights become chilly, I'll switch to a medium weight fleece (removing the fleece during the day). By the time the first major cold front with temperatures plummeting to 25º, strong winds and snow arrives, I'll place a poly tunnel over the fleece for added protection. I found this double protection to insure the crops viability through blizzards and 20 inch snowfalls. For the past decade, soil underneath the double protection hasn't froze.

The key here is night time temperatures, as they affect soil temperatures more than daytime temperatures in the winter months. Under the double protection of frost blanket and poly tunnel, the soil stays much warmer allowing growth, though slower, to progress.

During the winter when gifted warm days, remove the poly tunnel to prevent overheating and to allow more sunlight in. I pay close attention to the forecast, removing and replacing the poly tunnel as needed. Sometimes it is better to remove the frost blanket and keep the poly tunnel over the crops. It's a ballet, removing one or the other, or both and then replacing them in our ever changing weather. After a year or two of fall/winter vegetable gardening, you'll learn what protections works best for your crops. When enduring extended cold spells, just leave the tunnels over the crops and enjoy your time by the fire.

Thicker leafed vegetables like turnips, beets, kale and chard aren't as sensitive to the coldest weather as loose leaf lettuce, finicky in single digit temperatures. It's best to plant several different types of lettuce: leaf lettuce for first eating, then romaine and butterhead types during the coldest months. With the lettuces, most are cut and come again types – the regrowth slows considerably in January until about February 20th when the soil begins to warm enough for more rapid growth to begin again -- succession planting will extend the harvest.

Plant Tunnels

The tunnel concept is important. Plastic of the poly tunnel seems to transmit the cold to the plants, freezing them when in contact. To avoid damaging leaves, construct a tunnel to keep leaves off the plastic. I actually have two tunnels, a lower one that holds up the frost blanket, and a taller one for the poly tunnel with a layer of air several inches in width as insulation between them.

Poly tunnels can be purchased from gardening supply catalogs, or just by doing a Google search. I started out with both the large and small, fleece and poly tunnels that were pre-constructed. They last about 3 years. After that, I constructed by own devices to place over PVC pipes that I could just pull back and reach in.

To make the frost blanket cover, sew a sleeve wide enough to be able to insert a ¾ to inch wide PVC pipe. Make the cover wide enough to fit over your hoop and down to the soil for the width and length of the vegetable bed including several inches for sewing the sleeve, and at the long end to be able to tuck down. I have 2-4' x 8' raised beds, the PVC pipes are 8' in length to accommodate the beds.

For the poly tunnel, cut a length of 6 mil plastic sheeting long and wide enough to fit over the hoop, include sheeting extra on the ends to drape down from the top of the hoop to soil level, and then a further 6-8 inches extra on each end to anchor down (6-8 inches more on each end after allowing for enough length of plastic from top of hoop to soil at the ends). It's better to have too much at the ends than not enough. The 6' width of the 6' x 100' long roll of 6 mil plastic sheet is the perfect width for my 4' x 8' beds. Staple the plastic sheeting to 1” x 2” wide and 8' long pieces of wood (or whatever length you need for your bed). I use a thin, ¼” PVC tube for the inner hoop, and 1/2” for the upper hoop.

I also cut a foot length of wider 1 1/2” PVC pipe, driven into the ground for easy insertion of the upper hoop. I simple insert the smaller 1/4” hoop, that holds up the front blanket, directly into the soil. This is the basics. Depending on your set-up, the hoops can either go inside, or outside the raised bed; mine are inside.

Cold Frames

Cold frames will work just as well for growing vegetables. If you go this route, invest in one with a temperature control that will raise and lower the lid to let air in. Plants under glass can heat up quickly in small spaces under sunny winter skies. That's one reason I only concern myself with securing, nearly airtight, the poly tunnel during windy snowstorms and blizzards. Secondly, securing the polytunnel is important to keep it from blowing off in the midst of a winter gale (this can happen!).

Cloche-like devices can be used to similar effect as the poly tunnel. For a small plot of greens, a $5 clear plastic storage bin will make an effective greenhouse. One winter, on January 1st, I planted lettuce seeds and placed a lidless storage container top side down over it, securing it with a rock. Within 3 weeks the seeds germinated. Growth was slow. By mid March the greens were ready to eat. I chose the January 1st date as a good test for ground warmth and germination.

Cold frames allow seedlings up to an 8 week start when planted in late winter. Ideally, cold frames should face and/or slope south for best sun exposure and drainage. If the cold frame is tight, open slightly on warm sunny days.

To make a hot bed cold frame, pile 1 ½ feet of decomposing (raw) manure beneath the soil of a cold frame for a heat source.

Timing is Important

Because Swiss chard, kale and other vegetables take longer to mature, now is a good time to start your vegetable seeds indoors. I don't have grow lights, so this weekend I've sown some seeds in a starter kit and will allow it to be in morning sun. I may even bring them inside in the heat of the day until they germinate. This will be a first for me, so we'll see how it goes.

Begin planting cool season vegetables direct in the ground around Labor Day. Even the past two very hot summers, day and nighttime temperatures dropped around the first week in September. Have your beds prepared in advance so when it cools, all you have to do is plant the seeds. If starting a new bed, amend the soil with 4-8 inches of composted manure/composted cottonseed hulls or other composted material. If you're unsure about the soil quality, send some soil off for a soil analysis (Resources, Soil Testing); be sure to ask for organic content. In existing vegetable gardens, replenish the soil with 3 inches (or more depending on your soil quality) of compost. Be sure to invest in good quality compost that does not contain herbicide carryover (read here about Killer Compost).

Various books and guides advises that one can plant root crops for fall/winter harvest beginning from July 15th -October 15th. The beets and turnips had fair germination early. Carrots would germinate, but then fail. From year to year conditions will change, but I find as a general rule, planting around Labor day brings the best success. Finding the right balance between too hot to germinate and grow in mid-summer versus waiting until soil and air temperatures cool in October coupled with shortened and cooling days that hinder maturing before winter can be a challenge. I recommend planting in early September for the best chance of success. Thin seedlings according to instructions on the seed packets. But if turnips and beets don't mature by December, take heart, they actually continue to grow through January and February. Baby root crops are tender and delightful. But by February 15-20th, they need to be dug up and stored inside. The rapidly warming soil temperatures will cause the roots to turn woody. Amend the soil and plant an early spring crop.

Because we can't predict if we'll enjoy a long Indian summer and late winter, or an early snowfall in October, succession planting is a good way to hedge your bets. Don't worry if you're caught off guard with a mid-October snowstorm with only a frost blanket for protection. Temperatures are usually still too mild to do damage.

Cool Season Vegetables

The diversity of greens is the thing I love the most about cool season vegetable growing, far more than what one can find at the grocers, and much cheaper.

Green leaf lettuce

Red leaf lettuce

Romaine

Butterhead

Oakleaf

Bibb

Deer tongue

Mesculun

Iceberg

Arugula

Claytonia

Endive

Minutina

Muzuna

Radiccio

Sorrel

Spinach

Mache

Purslane

Cress

Mustard Greens

Tatsoi, pac/bok choi

Kale

Swiss Chard

 

Root and other vegetables possible for fall/winter harvesting:

Broccoli Raab

Onions, Scallions

Leeks

Shallots

Beets

Carrots

Kohlrabi

Parsnips

Radish

Rutabaga

Turnips

English peas (?)

 

Herbs can be over wintered under the poly tunnel and harvested fresh during the coldest months.

Parsley

Chives

Cilantro

Thyme

Winter Savory

Oregano

Rosemary

Sage

Rosemary and sage will usually make it through the winter fine without any protection. Garlic is planted in September and harvested at the end of June. A mulch cover is sufficient. Onions and scallions will winter over fine with just a mulch cover as well. The leafy greens of beets, kohlrabi and turnips can be added to salads when young.

In spring time, I grow English peas outside a tomato cage to grow upright. I tried this once in the fall, but wasn't able to protect the upper vines and pea pods from freezing. This September, I'll grow them ground level to be able to apply the double tunnel.

I may not have mentioned some of your favorite cool season vegetables and herbs. Give them a try and let me know.

The Top 15 Vegetable Seed Companies

If you're not sure which seed companies to trust, check out Mother Earth News list of top 15 sustainable seed companies. Many, but not all offer certified organic seeds, but all have signed the safe seed pledge*. Here's their list:

  1. Johnny’s Selected Seeds (Winslow, Maine)
  2. Seed Savers Exchange (Decorah, Iowa)
  3. Baker Creek Heirloom Seeds (Mansfield, Mo.)
  4. Burpee Seeds and Plants (Warminster, Pa.)
  5. Territorial Seed Company (Cottage Grove, Ore.)
  6. Seeds of Change (Rancho Dominguez, Calif.)
  7. Ferry-Morse Seed Company (Fulton, Ky.)
  8. Southern Exposure Seed Exchange (Mineral, Va.)
  9. High Mowing Organic Seeds (Wolcott, Vt.)
  10. Fedco Seeds (Waterville, Maine)
  11. Nichols Garden Nursery (Albany, Ore.)
  12. The Cook’s Garden (Warminster, Pa.)
  13. Botanical Interests (Broomfield, Colo.)
  14. Renee’s Garden Seeds (Felton, Calif.)
  15. Peaceful Valley Farm & Garden Supply (Grass Valley, Calif.)

Many seed companies have their catalog online and will send them free of charge. A person can learn a lot about growing vegetables from seed catalogs. One of the oldest surviving seed companies is D. Landreth Seed Company, selling seeds for 229 years. “Washington used Landreth's seeds at Mount Vernon and Jefferson at Monticello.” Landreth's catalog is as beautiful a catalog as it is informative, many descriptions containing the history of the vegetables. The 2013 catalog included detailed descriptions of flowers as well as vegetables and they've announced the 2014 catalog will describe herbs. Not free, it's priced at $7.95 and is a fun resource to own.


Benefits of Shifting the Season

One of the six basic principles of organic gardening is to plant in the preferred season. I've found trying to time the planting and growing of cool season vegetables in the spring to be a real challenge. Spring seems to be our most chaotic season, some years with real cold extending far into spring then a rapid warming into hot temperatures that cause many crops to bolt. I'm happy to start them in the fall, and then in early springtime, re-planting a few lettuces, onions sets, turnips, beets and radishes as desired using the same frost blanket tunnel. Over the years, I've found I enjoy vegetable gardening in the fall and winter far more than during our hot and windy spring and summer. The garden itself requires less time and effort, far less weeding and watering.

During quite cold spells, a winter garden can often go 2 weeks between watering with no ill effect. Because of the cold temperatures, the crops are held in a state of storage, so to speak. Your crops will fair better when watered weekly, weather permitting or as needed. Water when temperatures are above 45º so the water on leaves can dry before temperatures freeze again. A drip system or seep hose works well. The aim is to keep freezing rain, snow and ice off the vegetables.

Try to time winter harvesting in advance, when temperatures are above freezing. Greens cut when temperatures are below freezing will turn to mush, but once temperatures rise above freezing, they keep very well in the refrigerator for two weeks or more.

Having grown up and gardened first in Wisconsin, cool weather vegetables fresh from the garden was nearly always on our plate. In Wisconsin, the cool season vegetables were grown in the summer, not fall or winter. I'm not able to replicate growing every cool season vegetable I grew up eating, but I'm able to enjoy enough of them fresh and direct from the garden. It's pretty delightful to walk out to one's own garden and harvest leafy greens and herbs for the Thanksgiving, Christmas table and beyond.

Resources

*Safe Seed Pledge: "Agriculture and seeds provide the basis upon which our lives depend. We must protect this foundation as a safe and genetically stable source for future generations. For the benefit of all farmers, gardeners and consumers who want an alternative, we pledge that we do not knowingly buy or sell genetically engineered seeds or plants. The mechanical transfer of genetic material outside of natural reproductive methods and between genera, families or kingdoms poses great biological risks, as well as economic, political and cultural threats. We feel that genetically engineered varieties have been insufficiently tested prior to public release. More research and testing is necessary to further assess the potential risks of genetically engineered seeds. Further, we wish to support agricultural progress that leads to healthier soils, genetically diverse agricultural ecosystems and ultimately healthy people and communities."

Four-Season Harvest by Eliot Coleman, Chelsea Green Publishing Company, 1992, 1999.

Killer Compost and Herbicide Carryover

Mother Earth News, “Best Vegetable Seed Companies”, December 2011/January 2012, http://www.motherearthnews.com/organic-gardening/best-vegetable-seed-companies-zm0z11zsto.aspx?PageId=3#ArticleContent.

Mother Earth News, “Use Cold Frames to Grow More Food”, Barbara Pleasant, Spring, 2010.

The Gardener's A-Z Guide to Growing Organic Food, by Tanya Denckla, Storey Publishing, 2003.

Angie Hanna, August 3, 2013