Sigma 6
Sigma 6
Sigma 6
Sigma 6
Sigma 6
Sigma 6
Sigma 6
Sigma 6
Sigma 6
Sigma 6
Sigma 6
Sigma 6
Sigma 6
Sigma 6
Sigma 6

Sigma 6

Sigma 6

Rated 4.6 out of 5 stars
22 Reviews

Approx Size: 3m × 6m × 2.1m

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.


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

  • Wind resistant up to 100 km/h for those living in gusty climates.
  • Comes with two doors (one at each end).
  • Withstands a snow load of up to 91cm (160 kg / m²)
  • Made with a heavy-duty galvanized pipe frame and 6 mm double-wall polycarbonate panels.
  • Arched shape - so the wind, snow, and hail just slide off the sides. 
  • Extendable beyond 30 metres - 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.
  • Access to our private Facebook group to connect with and learn from other greenhouse owners.
Regular price €2.300,00 EUR
Regular price €2.500,00 EUR Save €200 Sale Sale price €2.300,00 EUR
Have questions? Call us 1-877-669-1286
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About Sigma 6

The Planta Sigma 6 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: 300cm x 213cm x 602cm

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 6 greenhouse is extremely pleasant to work in throughout the day due to the end-to-end airflow and the distinctive 2.1-metre roof height.

Snow Load Up To 32 psf (160 kg / m²)
160 kg / m² is equal to 91cm of fresh snow layer or 46cm of packed snow layer and is maintenance-free in the winter More About PSF
Wind Resistant up to 100 km/h
Sturdy greenhouse construction that resists winds up to 100 km/h
Extendable & Customizable
This greenhouse can be extended with additional expansion kits
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Rated 4.6 out of 5 stars
Based on 22 reviews
Total 5 star reviews: 16 Total 4 star reviews: 4 Total 3 star reviews: 1 Total 2 star reviews: 1 Total 1 star reviews: 0
91%would recommend this product
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22 reviews
  • RL
    Renee Latour H.
    Verified Buyer
    I recommend this product
    Location Tennessee
    Rated 5 out of 5 stars
    6 months ago
    Sigma 20’ Greenhouse

    We are loving the greenhouse. Thank you!

    Took about 7 days with 2 people to build, that’s with the learning curve and building up a level foundation.

    We chose to dig the holes and bury the legs instead of putting on concrete or 6x6’s.

    The panels had dust left inside them from the cuts from the factory and we used an air hose to remove the dust inside the panels before taping the ends. No big deal.

    It’s up and growing!

    Thank You, it’s a great purchase.

    PG Profile picture for Planta Greenhouses EU
    Planta Greenhouses EU
    6 months ago

    Great pictures! Your insights into the assembly process and innovative approach to foundation building are appreciated. If you ever need assistance or have more feedback, feel free to reach out. Happy growing 🌱🏡

  • TK Profile picture for Tammy logo
    Tammy K.
    Verified Buyer
    Location North Carolina
    Rated 3 out of 5 stars
    8 months ago
    Missing bolts

    The greenhouse itself seems to be of decent quality. My only complaints are we were shorted a large number of bolts, that coupled with the difficult assembly and poor instructions is why I gave it 3 stars.

    PG Profile picture for Planta Greenhouses EU
    Planta Greenhouses EU
    8 months ago

    Hi Tammy,

    Thanks for sharing your feedback! 🌿 We've taken these comments seriously and after a year of hard work, we've digitized our instructions for a smoother assembly experience:

    If you ever need further assistance, please don't hesitate to contact our customer service at 🌻

  • MM
    Marshall M.
    Verified Buyer
    I recommend this product
    Location Oregon
    Rated 5 out of 5 stars
    8 months ago
    Got it together for Fall...

    The only issues I had were some ambiguity in the assembly diagrams. We wanted some additional internal height so we mounted it with raised foundation. Overall very pleased. Still need to fine tune the fit between the door and the window.

    PG Profile picture for Planta Greenhouses EU
    Planta Greenhouses EU
    8 months ago

    Thank you for your feedback. We're working on improving our instructions for a better experience. If you have any questions or need help with the door and window fit, please email us at Enjoy your greenhouse!

  • JJ
    Jeremiah j.
    Verified Buyer
    I recommend this product
    Location Nevada
    Rated 4 out of 5 stars
    9 months ago

    It is an awesome greenhouse. I'm giving it 4 stars only because the instructions were hard to understand. I would also recommend having more than 2 people to help you build it.

    We haven't gotten bad weather yet where I'm at. So im giving that ranking a 3 for right now.

    PG Profile picture for Planta Greenhouses EU
    Planta Greenhouses EU
    9 months ago

    Thank you for your fantastic feedback and for choosing our greenhouse! 🌿 We appreciate your honest input about the instructions and the need for additional help during assembly. Your insights are valuable to us as we continue to improve.

    We hope your greenhouse serves you well and provides a fantastic gardening experience. 🌱🏡😊

  • JC
    Verified Buyer
    I recommend this product
    Rated 4 out of 5 stars
    10 months ago
    Very nice

    It is great for growing peppers and cucumbers in the summer with a shade cloth added to keep the temperature from getting out of hand. I like it so far

    PG Profile picture for Planta Greenhouses EU
    Planta Greenhouses EU
    10 months ago

    Hi Jonathan,

    Thank you for sharing your positive experience. We're glad to hear that your Sigma 20 is working well for your pepper and cucumber growing needs. Happy gardening! 🌶️🥒😊

Reviews LoadedReviews Added


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. Shipping prices will be shown on the checkout page based on your address.

  • 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.
  • 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. 



Residential Greenhouses

Are there doors on both ends of the greenhouse?

Yes! All of our Sungrow models come with manual doors and a manual window above the door on both ends of the greenhouse.

Do you have lean-to greenhouses?

Unfortunately, we do not have any lean-to greenhouses available at this time.

Do you make custom size greenhouses?

All of our products come pre-packaged by the manufacturer and can only be customized in length (2m extension). However, the height of the greenhouse can also be increased if placed on a base (up to 1.5m above the ground).

How is the greenhouse anchored to the ground?

Every greenhouse kit comes with optional legs that can be dug directly into the ground. The amount of legs included depends on the greenhouse size.

What is the frame made of?

The greenhouse frame is made out of heavy-duty galvanized steel.

What is the width of the door opening?

For our Sungrow models, the door opening width is 800mm.

What polycarbonate panels are used for residential greenhouses?

We use 6mm heavy-duty, double-walled polycarbonate panels with a UV-protected outside layer for our Residential Greenhouses.

What type of base/foundation is the best for me?

There are several different types of greenhouse bases, information, and pictures posted by our customers on our Customer Stories page and our Planta Facebook page. Additionally, you can learn more about "Types of Greenhouse Bases - With Pros & Cons of Each" on our blog.

FAQs Sigma ventilation window

Can I add windows for my greenhouse later?

Roof ventilation windows work as an add-on and can be installed only once the greenhouse installation is complete. Windows can be added later as well.

How many roof ventilation windows are recommended for the greenhouse?

It is strongly recommended to go with an even amount of roof ventilation windows. This is so you can place at least one on either side of the greenhouse. The amount of windows required depends on the greenhouse size, the climate you are in, and the types of plants that will be grown inside the greenhouse.

FAQs Sigma automatic ventilation window

How do the Automatic Ventilation Windows work?

Our Automatic Ventilation Windows do not require any batteries or electricity. A heat-activated mechanism will open/close the window once a certain temperature is reached.

What are the opening and maximum opening temperatures for the Automatic Windows?

The opening temperature is between 17 °C and 25°C, while the maximum opening is at 30 °C.

Sigma Greenhouses

What are the snow load and wind resistance on the Sigma models?

Sigma models can hold a snow load weight of 160 kg / m2 or 91cm of fresh snow on top of the greenhouse. The wind resistance is 100km/h.

Sigma Installation

Is there support post-purchase?

Absolutely! Our after-sales customer service team is available to answer any and every question. You can fill out our contact form or give us a call at 1 (877) 669-1286.

What resources are available to assist with greenhouse installation?

We offer several resources to help you with the installation process:

  1. Bilt App: Downloadable on the Apple Store and Google Play, it provides digitized step-by-step instructions.
  2. YouTube videos: A series of detailed video tutorials to guide you through the installation process.
  3. Printed Manual: Comes included with your greenhouse.
  4. Blog: Explore our blog for valuable insights such as "Expert Advice: 9 Tips For Installing Sungrow Greenhouses With Ease!"
  5. Customer-Only Facebook Group: Connect with other customers for valuable installation tips.

If you still need assistance, our customer service is ready to help via phone or email.

What type of base/foundation is the best for me?

This can vary depending on your location, gardening plans, and desired aesthetic. To better understand the different options available, you can find several different types of greenhouse bases, information, and pictures posted by Planta Greenhouse owners on our Customer Stories page and our Planta Facebook page. Additionally, you can learn more about it on our Greenhouse Bases blog.

Customization Options

Can I add my own vents, fans, heaters, and lights?

Of course! The polycarbonate is very easy to work with, and the galvanized steel frame is strong enough to support any additional accessories.

Can I get a longer greenhouse?

Most of our residential and commercial greenhouses are extendable up to 30 metres. Learn more about our extension kits for both the Sungrow and Sigma models.

How can I customize my greenhouse?

The customization possibilities are truly endless with a Planta Greenhouse. To help you get started, take a look through “16 Ways to Supercharge Your Greenhouse” on our blog.

Is hanging plants, heaters, and hammocks safe from my greenhouse frame? How much weight does it handle without affecting the guarantee?

It is safe to hang plants and accessories on a Sungrow greenhouse since each internal reinforcement arch can withstand up to 45.3 Kg. On the Sigma series, you can pre-drill the holes on the framing and hang small things. We would not suggest hanging anything heavier than 2.2 – 4.5 Kg per arch.

May I heat my greenhouse with firepits or similar?

You can use any heating source inside, like electricity, gas, propane, and even wood. It may be tricky to heat with wood, as you want to ensure that you keep the stove/pit away from the panels to prevent them from melting or burning if they are too close to the fire source. In this case, the customers ideally would want to come up with an exhaust system, making sure it’s not in contact with the panels, for being a flammable material.