Sigma 20

Sigma 20

4.6
Rated 4.6 out of 5 stars
34 Reviews

Approx Size: 10' × 19.5' × 7'

Imagine a garden filled with life yet untouched by time. A space where you can harvest heat-loving vegetables while a piercing winter storm is raging outside the door. A stable environment where vine-ripe tomatoes and succulent strawberries will thrive. A lovely quiet space to spend away from work, kids, and the chores of life.

Features

Strong and spacious: long-lasting construction, weather-resistant materials, and roomy design.

  • Wind resistant up to 65 mph for those living in gusty climates.
  • Withstands a snow load of 160 kg/m2 (32 psf), ideal for areas with moderate snowfall.
  • Made with a heavy-duty galvanized pipe frame and strong polycarbonate panels
  • Arched shape - so the wind, snow, and hail just slide off the sides.
  • Extendable beyond 100ft - so you can expand your greenhouse when you're ready.
  • Maintenance-free means you have more time to focus on your garden.
  • We offer a 5-year warranty because our greenhouse is heavy-duty and long-lasting.
Regular price $3,500 CAD
Regular price $3,800 CAD Save $300 Sale Sale price $3,500 CAD
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About Sigma 20

The Planta Sigma 20 is an urban gardener's dream come true. The quality heat-capturing materials allow for 3 or 4 season gardening, meaning you'll be able to harvest delicious fruits and vegetables beyond the outdoor growing season. Additionally, the rounded design is incredibly spacious, giving you the room to make the most out of your backyard garden.


Exact size: 118.1 x 83.9 x 236.99 inches


Feel confident knowing that the rust-resistant galvanized pipe frame is tough enough to withstand a variety of severe weather conditions – keeping your garden safe and sound throughout the year.

The greenhouse comes with:

  • two doors
  • two manual windows
  • the option to install multiple windows.

The Sigma 20 greenhouse is extremely pleasant to work in throughout the day due to the end-to-end airflow and the distinctive 7ft roof height.

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Extendable & Customizable
This greenhouse can be extended with additional expansion kits
 
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4.6
Rated 4.6 out of 5 stars
Based on 34 reviews
Total 5 star reviews: 25 Total 4 star reviews: 7 Total 3 star reviews: 1 Total 2 star reviews: 1 Total 1 star reviews: 0
94%would recommend this product
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34 reviews
  • JS
    Jacqueline S.
    Verified Buyer
    I recommend this product
    Rated 4 out of 5 stars
    Yesterday
    Chicago Cold, Cozy Greenhouse & a Love Story Inside

    We installed our Sigma greenhouse with an extension in 2022, making it 20 feet long—plenty of room for our growing needs and winter refuge. In the frigid Chicago climate, our Planta Greenhouse has been nothing short of a game changer. We use it to protect perennials like palm trees, bird of paradise, lavender, eggplant, peppers, crotons, tradescantia, geraniums, and elephant ears—especially the ones that can’t stay indoors due to our cats. All the pet-safe plants stay in the house, and everything else thrives inside the greenhouse. We also get a two-month head start on our annuals, which is huge for Chicago gardening. As of early February, we already have peppers, tomatoes, daisies, petunias, cosmos, morning glories, cucumbers, and forget-me-nots started.

    Our greenhouse has become our favorite place to be. We spend all winter inside, soaking up the sun while it's freezing or snowing outside. It’s our little haven—a space for plant care, self-care, and memory-making. In fact, it became so special that Marcin proposed to me right there in the greenhouse. Of course, I said YES!

    We added electric to the structure to make year-round use possible, and we installed a propane space heater for the coldest weeks. Two 65-gallon water jugs provide all the irrigation we need through winter. A compost bin adds warmth and allows us to reduce waste, and we’ve included shelves with grow lights to supplement sunlight. We also have a dedicated seed-starting station at the front of the…

  • A&
    Angela & Gregory R.
    Verified Buyer
    I recommend this product
    Rated 5 out of 5 stars
    5 days ago
    It Saved Our Plants During Hurricane Season

    For years, owning a greenhouse had been a dream of ours—and now it’s become a key part of how we live and grow. The greenhouse works in tandem with our outdoor garden to supply nearly all of the produce we consume. Once the colder months arrive, we transition entirely to greenhouse-grown food, eliminating the need to buy from the grocery store.

    Inside, we grow tomatoes, potatoes, peppers, beets, carrots, leeks, peas, string beans, broccoli rabe, kale, lettuce, mustard greens, basil, mint, eggplant, strawberries, and even lemon and fig trees, which we move in during winter along with our hibiscus and blueberries. It’s glorious watching everything thrive, even in below-freezing temperatures. The greenhouse has become our winter escape and has even protected many plants during hurricane season and high winds.

    Our buying experience was seamless—we didn’t even need to contact customer service. Reading customer stories from people in similar climates was incredibly helpful and gave us the confidence to move forward.

    We customized our setup by building the greenhouse on a 4x4 wood foundation attached to concrete footings, giving us an extra foot of interior height. Inside, we added raised beds, a pebble stone walkway, and sealed all seams with silicone for extra insulation.

    What we love most is the beautiful retro vibe of the greenhouse, paired with its sturdiness—it’s already held up to 50 mph winds without any issues. As we continue to learn and grow, we’re also exploring…

  • MD
    Mei D.
    Verified Buyer
    I recommend this product
    Rated 5 out of 5 stars
    1 week ago
    Morning Coffee in My Warm Greenhouse

    We purchased our Sigma 20 greenhouse from Planta in 2022, and it arrived within a week—even before we had finished building our foundation! As new greenhouse owners and gardeners, we've really enjoyed experimenting with a variety of plants inside: peppers, cucumbers, tomatoes, herbs, and even a surprise squash that popped up by accident.

    Our Planta Greenhouse has helped us extend our growing season and complement our outdoor garden. It’s been so rewarding to move toward year-round growing. To support that, we’ve added a fan for airflow and some LED lighting to keep things thriving even as the days get shorter.

    One of our absolute favorite things? Enjoying a hot cup of coffee inside the warm greenhouse on a frosty January or February morning—it honestly feels like a mini vacation. We'd love to add an extension someday (we already built the foundation to fit it)!

  • CW
    Chad W.
    Verified Buyer
    I recommend this product
    Location South Carolina
    Rated 5 out of 5 stars
    1 month ago
    Great build!

    Construction quality is awesome. Delivery and set up were great too.

    PG Profile picture for Planta Greenhouses Canada
    Planta Greenhouses Canada
    1 month ago

    Thanks, Chad! We’re glad you’re happy with the quality and delivery. Those photos look great too! 🌱

  • YE
    Yolande E.
    Verified Buyer
    I recommend this product
    Rated 5 out of 5 stars
    1 month ago
    Survives winter very well!

    It’s made a big difference in our gardening experience since 2022. Inside, we grow tomatoes, cucumbers, peppers, eggplant, and beans, while ground vegetables like carrots, potatoes, and spices are still grown outside in the garden. The greenhouse has definitely extended our growing season, and the vegetables thrive and grow quickly in the protected environment.

    Purchasing from Planta was a great experience—delivery was fast, the setup was straightforward thanks to the helpful videos, and customer service was excellent. Since setting it up, we’ve added raised beds, sidewalks, and some decorative outdoor plants and flowers around the structure. We also installed water connections and electrical wiring for ventilation and heat, which has made maintaining the space even easier.

    One of my favorite things about the greenhouse is how well it holds up through the winter. It’s easy to set up, simple to maintain, and preparing it each season by adding new soil and fertilizer is a breeze. Overall, we’re very satisfied and already looking forward to planting again next spring.

Videos

Shipping

Sigma 20 ships in these boxes:

  L, (in) W, (in) H, (in) Weight, (lbs) Quantity
Sigma Base 1 80 11 4 93 1
Sigma Base 2 78 24 3 93 1
Sigma Polycarbonate Base 82 44 4 58 1
Sigma Extension 78 21 3 63 1
Sigma Polycarbonate Extension 82 44 2 31 2
Total weight: 285

 

Greenhouses are amazing products, and they require special shipping and handling. That is the reason, we have been working diligently over the past year to secure preferential shipping rates for our customers. Most shipments across Canada and the US are between $250 and $450. 

  • We will contact you to confirm shipping price, based on your location and order size.
  • Shipping on most residential greenhouse orders is between $250 and $450, customers in remote areas may need to pay extra.
  • When you place your order, please make sure to enter the correct Phone and Address at checkout. You will be contacted by phone before the item is shipped. We cannot be responsible for deliveries to incorrect addresses.
  • As part of the delivery process, we require a contactable telephone number (for the courier company to contact you) before the item is shipped.
  • White glove delivery service isn't available. The greenhouse components are delivered in multiple boxes, the largest of which weighs 80lbs. The greenhouse will be delivered to your driveway. Please make arrangements to have the package moved to its installation location. 
  • We do not ship to PO Boxes, as in most cases you will need to sign for your item.  
  • Orders placed on weekends or public holidays will not begin processing until the next business day. 

 

FAQ