174-Season Extension Practices for Getting More from Your Garden, with Niki Jabbour

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When many gardeners are picking their last crops for the year and getting ready to say goodbye to their gardens until spring, Niki Jabbour doesn’t slow down when temperatures drop. Though Niki lives in USDA zone 5b in Halifax, Nova Scotia, where winter temperatures can plunge to 0 degrees Fahrenheit, she can harvest fresh vegetables year-round because she implements season-extension practices and structures in her garden.

A little more than a year ago, I visited Niki’s 2,000-square-foot garden to film an episode of my public television program, “Growing a Greener World.” It was really fun tagging along with Niki and trying to keep up with her. So much has transpired in Niki’s garden and in her career since I left — including completing her upcoming book, “Gardening Under Cover: Techniques for a More Productive, Weather-Resistant, Pest-Free Vegetable Garden” — and I was excited to catch up with her this week.


Niki Jabbour

Niki recently wrote an in-depth book all about using structures like row cover, shade cloth, low tunnels, cold frames, and hoop houses to create controlled growing environments.
(photo: Ⓒ “Growing Under Cover” by Niki Jabbour, (Storey Publishing, 2020). Cooked Photography)


I was honored to be asked to write a blurb for “Gardening Under Cover,” Niki’s in-depth guide on season extension using row cover, shade cloth, low tunnels, cold frames, hoop houses and other protective structures to create controlled growing environments for vegetables to thrive in. Take it from Niki: You don’t need a $100,000 greenhouse to garden year-round.

Not only are garden structures essential for extending the growing season, Niki reports that it also cuts down on losses to deer, raccoons, groundhogs, chipmunks, squirrels and rabbits — the veritable zoo that is her backyard.

Gardening in a “Non-Book Year”

Niki’s garden doubles as the backdrop for the photographs in her books. She demonstrates the techniques that are described in her books and grows all the vegetables she is writing about — while also keeping the garden neat and photogenic. That adds an extra layer of work that most vegetable gardeners never worry about. In 2019 she gardened with book photos in mind, but 2020 was “a non-book year,” she says, and she had the freedom to try whatever she wanted.

Being 2020, things didn’t work out as planned. It took much longer for Niki to receive the seeds she wanted, as seed companies saw an influx of orders like never before. She didn’t get to grow everything she wanted, and grew some things she hadn’t expected to.

In some ways, conditions were more favorable this year, as it’s been hot and dry in Nova Scotia and she harvested bushels of tomatoes, compared to 2019 when conditions were cool and wet and she got no tomatoes. But 2020 also delivered more hail, plus a frost warning came in August. She says traumatic changes are happening due to climate change and it has affected what she can grow when. 


Basket of tomatoes

Hot and dry conditions allowed Niki to harvest bushels of tomatoes this year, compared to 2019 when conditions were cooler and wet and she got fewer tomatoes. (photo: Niki Jabbour)


As of now, she is pulling up bush bean plants, harvesting soybeans and transplanting lettuce starts outdoors. She’s clearing space for even more crops, such as spinach, arugula, scallions, bok choy, cilantro, Swiss chard, kale, turnips, radishes and carrots. 

Niki is readying her cold frame and polytunnel for the first frost in one or two weeks, and sometime before the ground freezes, she’ll be getting garlic planted to harvest next spring or summer.


Niki Jabbour in the garden

Niki’s photogenic garden is the backdrop for the beautiful photography that fills her gardening books.
(photo: Ⓒ Growing Under Cover by Niki Jabbour, (Storey Publishing, 2020). Cooked Photography)


Fall in Zone 5B

While it’s still hot outside, with dry soil and pest pressure, Niki suggests starting seeds indoors for fall planting. It’s a no-brainer that gives gardeners such a head start, she says.

Certain seeds should be direct sown, such as turnips, carrots, arugula and spinach, and she is planting those outdoors right now. She says root crops in particular grow much better root systems when seeds are sprouted in the garden rather than started indoors and transplanted. Even though most root crops and leafy greens are cool-season crops, they still will grow well in warm temperatures as long as the soil is kept moist, she says.


Niki Jabbour holding parsnips

Parsnips are another great root crop to plant in late summer or early fall. (photo: Ⓒ Growing Under Cover by Niki Jabbour, (Storey Publishing, 2020). Cooked Photography)


One of Niki’s favorite vegetables is cauliflower, and while it can be grown in spring, she prefers to plant in fall. Cauliflower planted in spring will bolt when a little heatwave comes and will not deliver much of a head. In her experience, cauliflower thrives in fall as days progressively get cooler and shorter.

Niki has the same recommendation for watermelon radishes and daikon-type radishes, which she plants in August or early September and then harvests up until Christmas. She does deep-mulch the radishes when cold temperatures come.

Niki says the lesson here is not to give up on a plant because it didn’t do well the first time you tried growing it in your environment. Try it again at a different time of year when it may be much happier.

While spring goes back and forth, weather-wise, for Niki, from warm to cold and from hot to hail and snow, fall is much more temperate and steady with more consistent moisture. 

For fall gardening success, look at your first frost date and count backward, Niki advises. If you have a seed for a 35-day turnip, for instance, plant it about 40 days before frost is expected.


Niki Jabbour

Fall is usually more temperate than spring with more consistent moisture, so it’s a great time to grow food. Just look at your first frost date and count backward to know when to plant crops.
(photo: Ⓒ Growing Under Cover by Niki Jabbour, (Storey Publishing, 2020). Cooked Photography)


Three Camps of Vegetables

Niki breaks vegetables down into three categories: warm-season, which grow between the last frost date and first frost date; cool-season, which are grown in spring or fall; and cold-season, which are quite frost tolerant. 

Swiss chard, for example, is a wonderful green that grows great in fall but is not that frost tolerant and will be done for after a couple of frosts. But then certain leafy greens like kale, mache (also known as “corn salad”), spinach, arugula and mizuna (Japanese mustard) are very cold tolerant and can be harvested, with protection such as a cold frame or low tunnel, well into winter. 

But Niki won’t grow a vegetable just because she knows when it will thrive in her zone. She asks herself, what do I want to eat? She then matches what she enjoys on her plate to the seasons and studies seed catalogs carefully to learn which taste their best after frost, like carrots, leeks, beets or kale. Carrots in particular taste sweeter because they increase sugar production in the cold as a natural antifreeze.


Niki Jabbour holding kale

Certain leafy greens like kale are very cold tolerant well into winter if grown under the proper protection.
(photo: Ⓒ Growing Under Cover by Niki Jabbour, (Storey Publishing, 2020). Cooked Photography)


Enviable Polytunnel

A polytunnel is a garden structure made from supports covered with a clear plastic (polyethylene) sheet to block the wind and collect solar energy. Niki’s 14-foot-by-24-foot polytunnel, with a strong steel frame and 6 mil UV-resistant greenhouse-style polyethylene, is in its third season. It’s already been through three hurricanes in that time and Niki reports it’s come through with flying colors.

Though the polytunnel seemed big when she first got it and she wondered how she would ever fill it, Niki says it was full just two weeks later. In spring, it’s where she grows greens and root crops. In summer, she shifts it to tomatoes, cucumbers, melons, eggplants and peppers. Now that fall is arriving, Niki is transitioning the polytunnel back to root crops and greens for fall and winter harvesting.

Niki says she’s never met anyone who put a garden structure up who wishes they had gone smaller. Some say they thought they found the perfect size structure but now wish they had two. Of course, budget and space are considerations. Start with a relatively level area that gets good sun — eight to 10 hours a day or more with no shade from trees or other structures. Building on even a slight slope will increase costs because fill will be needed to level the space. Also, consider community bylaws that may prohibit garden structures over a certain size or of certain styles.

Polytunnels can be simple half-cylinders, like a Quonset hut, but there are other styles as well, such as a Gothic arch, like Niki’s. Niki prefers the Gothic arch because of its peak, which sheds snow more readily — something to consider if you live in an area that gets a lot of snow.

A polytunnel or greenhouse increases food security and decreases food miles, which reduces one’s carbon footprint, Niki notes. But not everyone appreciates that or finds them to be attractive, so know what the rules are before purchasing something your community might not let you keep.

Niki’s polytunnel has raised beds inside and a gap down the center where she can place fabric pots as needed for growing tomatoes and other vertical crops that grow up twine hanging from the tunnel’s trusses. She chose against filling the entire tunnel with permanent beds so she could play with the space a bit and make changes from season to season. She even has a sitting area inside where she works on her books and drinks tea. Even in January, if it’s above freezing and sunny outside, it can be 65 or 70 degrees Fahrenheit inside the polytunnel. 

Due to the coronavirus pandemic and the renewed interest it has stimulated in growing one’s own food, there has been a greenhouse boom in Nova Scotia, Niki says, with hundreds of new DIY or kit structures cropping up.


Niki Jabbour in garden

Niki’s polytunnel has raised beds inside and was designed with a Gothic arch to allow snow to slide off more easily.
(photo: Ⓒ Growing Under Cover by Niki Jabbour, (Storey Publishing, 2020). Cooked Photography)


Succession Planting and Season Extension

It’s easy to start practicing succession planting with no great expense. If you direct sow, you’ll have no new expenses beyond seeds. If you start plants indoors, you may need to buy seed-starting mix and grow lights — but the rewards are ten-fold. In fact, Niki uses her grow lights all summer and fall to give plants a head-start before they go in the garden.

Succession planting comes down to planting vegetables frequently, whenever you have open space in the garden. You can fill those spaces with transplants or by direct seeding.

To have the most success in succession planting, it takes some planning ahead. When you order seeds in late winter or early spring, make sure you have the seed varieties you’ll need in the quantities you’ll need. Beans or cucumbers, for instance, can be planted before summer and late in summer, for two harvests without the aid of any season extenders.

If you wish to invest more in succession planting to maximize your garden’s output per square foot, you can plant both earlier and later in the season with the aid of inexpensive structures such as hoop tunnels or cold frames that you can build easily. Niki builds her own hoop tunnels using a metal bender to create the arches out of half-inch metal conduit. She spaces the U-shaped arches 3 feet apart and covers them in 6-mil poly. Alternatively, half-inch PVC conduit secured in the ground with rebar makes good arches.


Raised bed with season extender

Inexpensive structures like this hoop tunnel can be built using a metal bender to create the arches out of half-inch metal conduit.
(photo: Niki Jabbour)


There are other inexpensive, sneaky ways to extend the season and grow more food, Niki said. Glass jars, salad containers, water bottles and milk jugs with their bottoms removed can all work as frost protection for the lettuce in your garden. A foot or two of loose shredded leaves or straw applied before the ground freezes will extend the season for carrots, leeks, beets and winter radishes. She uses a lawnmower on maple and birch leaves to shred them up for mulch, and an old row cover or an old bed sheet to keep the mulch from blowing away. (As an added benefit, straw and leaves especially will also provide valuable organic matter to your soil as it decomposes.)

Because winter crops may be covered in both deep mulch and a layer of snow, Niki puts tall color-coded stakes in the ground when she plants — red for beets, orange for carrots, etc. — to make it easier to harvest in the middle of winter. She says it’s an amazing feeling digging home-grown carrots in January or February.

Advice for First-Time Gardeners

Niki’s advice to people trying their hand at gardening for the first time is to start off small and not to get discouraged, even if they find they bit off more than they could chew. What failed to flourish this year might have everything to do with Mother Nature rather than your own mistakes, and it may do better next year. But every mistake is a learning opportunity, and what gardeners have in common is they are resilient — because there’s always next year.

She recommends ordering seeds early because seed companies are telling her that people are still ordering like mad in preparation for 2021 gardens.

The questions Niki is hearing most right now relate to cold frames, like when to plant a certain crop, how often to water, or what can be overwintered in a cold frame. She tries to answer every question she receives — and the questions are often also answered in her books. Many people have learned how to use cold frames effectively through Niki. She says it’s the best feeling when people harvesting from their cold frames tag her on social media in their posts.


Cold frame

A simple cold frame is an inexpensive and effective way for first-time gardeners to try extending the season. (photo: Courtesy of Niki Jabbour)


If you haven’t listened yet to my conversation with Niki Jabbour, you can do so by scrolling up the page and clicking the Play button on the green bar.

Do you have a favorite method for extending the growing season? Share with us in the comments below.

Links & Resources

Episode 022: The Year-round Vegetable Gardener with Niki Jabbour

Episode 045: Succession Planting: Practical Tips For Growing More Food

Episode 122: Fall Vegetable Garden Success: Best Plants and Tips for Cool-Season Growing

joegardenerTV YouTube: Easy Edibles for Every Fall Vegetable Garden

joegardenerTV YouTube: How to Build a Simple Cold Frame

joegardener Blog: The Best Soil Temperature for Seed Germination

joegardener Blog: What to Grow in a Fall Vegetable Garden

joegardener Online Gardening Academy: Three popular courses on gardening fundamentals; managing pests, diseases & weeds; and seed starting!

joegardener Online Gardening Academy Seed Temperature Chart

joegardener Online Gardening Academy Essential Gardening Fundamentals: The basics on healthy soil, planting, watering techniques, composting, raised bed and other gardening methods, fertilizer, the many benefits of mulch, and more.

joegardenerTV YouTube

joegardener Newsletter

joegardener Facebook

joegardener Facebook Group

joegardener Instagram

joegardener Pinterest

joegardener Twitter

Growing a Greener World® 


GGW Episode 1013: The Year-Round Vegetable Gardener 

Savvy Gardening

Niki Jabbour Instagram

Niki Jabbour YouTube

“Gardening Under Cover: Techniques for a More Productive, Weather-Resistant, Pest-Free Vegetable Garden” by Niki Jabbour

“The Year-Round Vegetable Gardener: How to Grow Your Own Food 365 Days a Year, No Matter Where You Live” by Niki Jabbour

Niki Jabbour’s Veggie Garden Remix: 224 New Plants to Shake Up Your Garden and Add Variety, Flavor, and Fun” 

“Groundbreaking Food Gardens: 73 Plans That Will Change the Way You Grow Your Garden” by Niki Jabbour

Johnny’s Selected Seeds Metal Benders

Row cover

Park Seed® – Our podcast episode sponsor and Brand Partner of – Use code Joe20 for 20% off your next order

Rain Bird® – Our podcast episode sponsor and Brand Partner of

*Disclosure: Some product links in this guide are affiliate links, which means we would get a commission if you purchase. However, none of the prices of these resources have been increased to compensate us. None of the items included in this list have any bearing on any compensation being an influencing factor on their inclusion here. The selection of all items featured in this post and podcast were based solely on merit and in no way influenced by any affiliate or financial incentive, or contractual relationship. At the time of this writing, Joe Lamp’l has professional relationships with the following companies who may have products included in this post and podcast: Rain Bird, Corona Tools, Milorganite, Soil3, Park Seed, and Exmark. These companies are either Brand Partners of and/or advertise on our website. However, we receive no additional compensation from the sales or promotion of their product through this guide. The inclusion of any products mentioned within this post is entirely independent and exclusive of any relationship.

About Joe Lamp'l

Joe Lamp’l is the creator and “joe” behind joe gardener®. His lifetime passion and devotion to all things horticulture has led him to a long-time career as one of the country’s most recognized and trusted personalities in organic gardening and sustainability. That is most evident in his role as host and creator of Emmy Award-winning Growing a Greener World®, a national green-living lifestyle series on PBS currently broadcasting in its tenth season. When he’s not working in his large, raised bed vegetable garden, he’s likely planting or digging something up, or spending time with his family on their organic farm just north of Atlanta, GA.

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