Sigma Small Greenhouse

Compact Backyard Kits, 6.5 ft Wide

4.8 · 412 reviews
Save $300
Sigma 200 (Gen III) greenhouse with transparent panels on a grassy area in front of a house.
Sigma 2x6 (Gen III) greenhouse in a field with trees and sky in the background by Planta Greenhouses EU.
Sigma 200 (Gen III) Greenhouse interior with soil floor and glass walls, outside view of grassy field.
Interior of a Sigma 200 (Gen III) greenhouse with shelves and a ladder.
Metallic door with a handle and key lock on a Sigma 200 (Gen III) greenhouse door.
Clear polycarbonate Sigma 200 (Gen III) greenhouse structure with metal frame in a warehouse setting
Partial view of a Sigma 200 (Gen III) greenhouse with transparent panels and metal frame.
Partial view of a Sigma 200 (Gen III) greenhouse with a sliding door
Metal Sigma 200 (Gen III) greenhouse structure with curved roof and transparent panels on a concrete floor.
Interior of a Sigma 20 (Gen III) greenhouse with transparent walls and a door.
Modern Sigma 200 (Gen III) greenhouse with transparent walls and a curved roof in a garden setting - by Planta Greenhouses EU.
Clear Sigma 200 (Gen III) greenhouse with open door in a garden setting - by Planta Greenhouses EU.

Sigma Small 20

Sigma Small greenhouse kits are arched backyard greenhouses rated for a 265 kg/m² (55 psf, 4.5 ft) snow load and 100 km/h wind, with 6 mm twin-wall polycarbonate panels and a 10-year warranty. They're for sale in 5 sizes, all 6.5 ft wide, so you can choose the length that fits your space. Find your greenhouse.

Size: Sigma Small 20 · 6.5′ × 20′Size guide
$4,550$4,850Save $300
Free shippingTo nearest terminal
10-year warrantyFrame & panels
Pre-cut panelsFor easier installation
Guided assemblyVideos and live chat
Questions? Talk to a grower.

Mon–Fri 9am–5pm EST or Send a Message

Call us1-877-669-1286

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Which size is best for your garden?

Get this sizing guide with photos and bed layouts.

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pg guide cover
  • Insulated Doors NEW – Helps reduce heat loss and drafts, creating a more stable growing environment and improving energy efficiency.
  • Upgraded Door Handles NEW – Smooth, reliable operation with a sturdy grip for easier daily access and long-term durability.
  • Aluminum Polycarbonate Trim NEW – Securely locks panels in place along the arch for added strength, better weather resistance, and a clean, finished look.
  • Window/Door Latch NEW - Makes the door and window open together.
  • Improved Snow Load [NEW] - Rated for a snow load of up to 265 kg/m² (55 psf, 4.5 ft).
  • Wind resistant up to 100 km/h for those living in gusty climates.
  • Comes with two doors (one at each end).
  • Made with a heavy-duty galvanized steel frame and 6 mm twin-wall polycarbonate panels.
  • Arched shape - helps wind, snow and hail slide off the sides.
  • Extendable beyond 100 ft - 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 10-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.
  • The Sigma Small Greenhouse is available in 5 size configurations. Plus, you may purchase an extension kit, to extend the length of the greenhouse.
  • Extendable & Customizable
  • Snow Load Up To 265 kg/m² (55 psf, 4.5 ft) 
  • Wind Resistant up to 100 km/h
  • We offer a 10-year warranty because our greenhouse is heavy-duty and long-lasting.

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. 

 

Free guide

The Beginner's Guide for Greenhouse Owners

Tell us where to send it and it's yours.

Sigma Small Greenhouse Measurements

Sigma Small 20 · 6.5′ × 20′

3D view
Side view

Compare Sigma Small Greenhouse Sizes

This greenhouse comes in several size configurations. Every greenhouse extends in 6.5 ft sections, so pick the length that fits your plot and your plans.
Sigma Small greenhouse beside a stone path and flowering shrubs Sigma Small Compact
6.5′ × 6.5′
Sigma Small greenhouse front with both doors open and a gardener inside Sigma Small Urban
6.5′ × 13′
Sigma Small greenhouse front with the door and window open, next to a house deck Sigma Small 20
6.5′ × 20′
Sigma Small greenhouse with the door open on a garden plot Sigma Small 26
6.5′ × 26′
Sigma Small arched greenhouse side view with the door and window open Sigma Small 32
6.5′ × 32′
Price
Sale$2,850
$2,750
Sale$3,850
$3,650
Sale$4,850
$4,550
Sale$5,850
$5,450
Sale$6,850
$6,350
About
Starter size: shelves or a bed on one side for greens, herbs and seedlings.
A bed along one side and shelving on the other for seedlings and herbs.
Room for a long bed, a few tomato plants and a potting shelf.
Long beds for greens and tall crops, with a narrow center path.
The largest Sigma Small: a long growing space for beds, shelving and climbing crops.
Width
6.5 ft width
6.5 ft width
6.5 ft width
6.5 ft width
6.5 ft width
Length
6.5 ft length
13 ft length
20 ft length
26 ft length
32 ft length
Height
8 ft height
8 ft height
8 ft height
8 ft height
8 ft height
Sq ft
42 sq ft
85 sq ft
130 sq ft
169 sq ft
208 sq ft
Owner reviews
4.8 Read all 412 reviews
Read all 412 reviews
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Dome-shaped Greenhouse
About this model

Dome-shaped Greenhouse

Sigma greenhouse has a dome-shaped arch which sheds snow and rain, and the galvanized steel frame with 6 mm twin-wall panels is rated for 55 psf of snow. Insulated doors help keep the warmth in.

Winter-Ready Greenhouses
Why Planta Greenhouses

Winter-Ready Greenhouses

Heavy-duty greenhouses used by 25,000+ growers since 2019, designed to withstand heavy winters. Backed by a 10-year warranty and live customer support.

Arrives in labeled boxes
Shipping & assembly

Arrives in labeled boxes

Ships across Canada, and most residential orders ship for $250–$450 depending on your location. Every panel is pre-cut and every bag of hardware is labeled, so two people can build it with the step-by-step videos.

Questions? Talk to a grower.

Mon–Fri 9am–5pm EST or Send a Message

Call us 1-877-669-1286