Sigma 8
Sigma 8
Sigma 8
Sigma 8
Plata Greenhouses - Sigma 26 Greenhouse
Sigma 8
Sigma 8
Sigma 8
Sigma 8
Sigma 8
Sigma 8
Sigma 8

Sigma 8

Sigma 8

4.9
Rated 4.9 out of 5 stars
17 Reviews

Approx Size: 3m × 8m × 2.1m

Bring the tropical heat of the Caribbean to your own backyard in the middle of winter. Enjoy your own micro-climate where you can grow sweet new fruits and flavorful vegetables beyond the limitations of the weather outdoors — a space where you can harvest, snack, or sit and feel wonderful among your plants.

Features

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 €2.389,76 EUR
Regular price €2.926,23 EUR Save €536,47 Sale Sale price €2.389,76 EUR
Have questions? Call us 1-877-669-1286
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About Sigma 8

The Sigma 8 was designed with a focus on spaciousness and stability. This greenhouse is perfect for 3 or 4 seasons of growing, allowing you to harvest fresh fruits and vegetables well into the colder months. Our Sigma greenhouses are built to last, featuring a rounded design and creative construction that brings heavy-duty greenhouse engineering into your own backyard.

Exact size: 300cm x 213cm x 802cm

The end-to-end airflow, spacious size, and high 2.1-metre roof height make this a comfortable place to garden throughout the day.

The greenhouse comes with:

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

The galvanized pipe frame is both rust-resistant and durable. In addition, the construction can withstand moderate to extreme weather conditions, ensuring your garden will stay safe and flourish throughout the seasons.

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Extendable & Customizable
This greenhouse can be extended with additional expansion kits
 
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Reviews

4.9
Rated 4.9 out of 5 stars
Based on 17 reviews
Total 5 star reviews: 16 Total 4 star reviews: 1 Total 3 star reviews: 0 Total 2 star reviews: 0 Total 1 star reviews: 0
100%would recommend this product
Slide 1 selected
17 reviews
  • NA
    Neil A M.
    Verified Reviewer
    I recommend this product
    Location British Columbia
    Rated 5 out of 5 stars
    1 week ago
    Costumer Service

    Bought Sima 2021 Euro a couple of years back. Got it assembled last year and finally got auto vents installed this spring. One vent cyl did not function, it would not collapse. I got in contact with Murad at Costumer Service and he assured me that even though the warranty had expired they would send along a replacement. Logistic Coordinator Paulette followed up and new cyl arrived and works great. Excellent service . Finishing the install of a bench and drip system. Looking forward to great growing results.

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

    Thanks so much, Neil! We’re glad Murad and Paulette were able to help and that everything’s working smoothly now. Wishing you a fantastic growing season ahead!

  • SM
    Shawnee M.
    Verified Buyer
    I recommend this product
    Rated 5 out of 5 stars
    1 month ago
    Turning It Into a 4-Season Greenhouse

    We grow a variety of herbs, tomatoes, several types of peppers, peas and beans, onions, garlic, mint, starters, and squash plants. It’s been a learning experience, but the greenhouse is helping us extend our growing season. Last year, during a grasshopper infestation, we had to transplant surviving outdoor plants into the greenhouse, and it provided the protection we needed. We’re now working on converting it into a 4-season greenhouse.

    Customer service was great and the product itself has performed well. We purchased the sunshade, which made a big difference. We also installed a trellis for vining plants and are currently working on setting up a heating and cooling system, along with purchasing greenhouse shelving.

    What we appreciate most is the protection it provides from critters and the elements, along with its spacious design—perfect for raised beds. Our students are about to help clean it out and get started on early spring planting. If we had the funding, we would install another one. As a non-profit farm running a school program, we’re currently applying for a grant to cover electrical installation so we can move toward full 4-season use.

  • GK
    Greg K.
    Verified Buyer
    I recommend this product
    Rated 5 out of 5 stars
    1 month ago
    A Beautiful Greenhouse for My Wife

    I installed our first greenhouse, a Sigma model, in late fall of 2024. While we haven’t started growing yet, we’re just now getting ready to use it. My wife plans to grow vegetables, flowers, herbs, and microgreens. We’re expecting earlier seedling starts and a longer growing season overall.

    Buying from Planta was very easy. I did a lot of research beforehand and chose Planta for its combination of value and quality. Customer service has been great—a real person answers the phone! I called once with pre-purchase questions and twice more during assembly. Each time, my questions were answered clearly and promptly.

    We placed the greenhouse on the east side of our barn to help protect it from strong summer storm winds. I poured a cement slab with a 4" curb and anchored two 2"x4" treated boards on top, giving the greenhouse an extra 7" of height. I also installed a lateral 5" drain in the floor to help with water flow.

    My favorite thing about this greenhouse? It's a thing of beauty—and I bought it for my wife, who has always dreamed of having one. We’re both very happy with it and would highly recommend it. The combination of video guides, printed instructions, and the BILT app made installation easier than you’d think.

  • RA
    Ravil A.
    Verified Buyer
    I recommend this product
    Rated 5 out of 5 stars
    3 months ago
    A Warm Winter Garden

    We installed our Planta Greenhouse in 2024, and it’s already made a huge difference in our gardening experience. This was our first greenhouse, and it allowed us to start the growing season much earlier than usual. Even in winter, the greenhouse stays warm enough to comfortably work inside on sunny days—something I never expected to enjoy so much. I was even able to harvest cucumbers into mid-October!

    Inside, we’ve grown tomatoes, cucumbers, basil, and a variety of other herbs. To optimize the space, we built a solid wood foundation with raised garden beds and a concrete walkway between them. Gravel bedding and proper drainage around the structure have made it both functional and low-maintenance.

    Buying the greenhouse from Planta was straightforward. We took advantage of a Christmas discount, which inspired us to make the purchase sooner than planned. Delivery was on time, and although installation was a bit time-consuming (as expected for a first-timer), the process went smoothly. I’m genuinely impressed with the quality and performance of this greenhouse—and I’m really enjoying it!

  • AD
    Adriane D.
    Verified Buyer
    I recommend this product
    Rated 5 out of 5 stars
    3 months ago
    3 Sigma Greenhouses Later We Keep Choosing Planta

    After moving twice in five years, we've now installed our third Planta greenhouse—this time a 26-foot Sigma model alongside extra polycarbonate panels, which we used to create a custom lean-to greenhouse against our garage. With each build, we’ve refined our setup process, learning how to make installation smoother and more efficient every time.

    Our large greenhouse is dedicated to cabbages, broccoli, cauliflower, leeks, celeriac, and even a couple of grape varieties, with netting on the doors to help keep cabbage moths out. In our new lean-to space, we’re planning to grow tomatoes, peppers, squash, pumpkins, and cucumbers. We like to use grow bags for flexibility and continue to plant staples like potatoes, onions, and beans outdoors. Even our chicken coops benefit from leftover polycarbonate panels—adding natural light while keeping them warm and dry.

    The Sigma greenhouse has truly improved our gardening experience. It’s helped us extend our growing season and grow varieties that normally wouldn’t thrive in our climate. Planta’s greenhouses are incredibly sturdy—ours held up through heavy snowfalls, and after experiencing some damage from Hurricane Fiona, we added L-brackets and longer screws for extra reinforcement. These little adjustments have made a big difference, especially for older hands during assembly.

    Ordering from Planta is always a breeze. Their quality is unmatched, and the support team has consistently provided excellent service. That’s why we’ve returned…

Shipping

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. 

 

FAQs

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 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 +44 (800) 208-8945.

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 fire pits 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.

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.