Modern Greenhouse Kits for Sale | Durable Glass Greenhouses

What Makes This Modern Greenhouse Different?

Most greenhouses follow a familiar formula with peaked roofs, straight walls, and a purely functional design. This modern greenhouse takes a completely different approach.

Instead of a traditional A-frame, the Janssens lean-to design features a sleek, single-slope roof that creates a dramatic full-height glass wall. The result is a space that captures more natural light while delivering a clean, architectural look that complements contemporary homes and outdoor living areas.

With its black powder-coated aluminum frame and precision-engineered glass panels, this glass greenhouse is built not just for growing,  but for elevating your entire backyard environment.

Benefits of a Modern Lean-To Greenhouse

A high-quality modern greenhouse should do more than look good!   It should perform in real conditions. This design is built to handle Colorado’s unpredictable weather while giving you full control over your growing environment.

A lean-to structure isn’t just about aesthetics,  it delivers real, practical advantages, especially for homeowners in climates like Colorado.

Its single-slope structure helps maximize sunlight exposure while creating a more space-efficient footprint compared to traditional greenhouse designs. This makes it a smart option for backyards where layout, access, and light all matter.

Key advantages include:

• Tempered safety glass panels (4mm) for maximum light transmission and strong resistance to hail and wind
• Automatic roof vent openers that regulate temperature without electricity
• Side windows and louvre vents for effective cross-ventilation during warmer months
• Wide double doors for easy access with tools, plants, and equipment
• Reinforced 17-gauge aluminum rafters designed to handle snow loads and harsh weather
• Long-term protection with a 15-year frame warranty and 10-year material coverage

Available sizes:

• M23 (8' x 10') – 79 sq. ft.
• M34 (10' x 15') – 150 sq. ft.
• M36 (10' x 20') – 200 sq. ft.

Is a Lean-To Modern Greenhouse Right for Your Space?

A lean-to modern greenhouse is a smart choice for homeowners who want a streamlined, space-efficient structure without sacrificing growing capacity.

Its single-slope design makes it easy to position alongside existing outdoor features like fences, patios, or garden walls,  while still working as a standalone structure when needed. This flexibility allows you to adapt the layout to your space, sunlight conditions, and how you move through your yard.

It’s especially useful in tighter spaces where a full freestanding greenhouse might feel oversized, but you still want a high-performance growing environment.

You also get layout flexibility. Doors and windows can be positioned to align with pathways, airflow, or outdoor living areas,  giving you a tailored feel without the complexity of a fully custom build.

For homeowners in Denver and across the Front Range, professional greenhouse assembly is available to ensure everything is installed correctly and performs as expected.

Modern Greenhouse vs Traditional Greenhouse

Choosing between a modern greenhouse and a traditional model comes down to performance, durability, and design.

Feature	Modern Lean-To Greenhouse	Traditional Greenhouse
Roof Design	Single-slope, contemporary	A-frame peaked
Frame Material	Powder-coated aluminum	Basic aluminum or steel
Glazing	Tempered safety glass	Polycarbonate or standard glass
Heat Efficiency	Efficient airflow and heat retention design	Varies
Space Use	Compact, wall-mounted	Requires open yard space
Weather Resistance	Built for snow and hail	Varies widely

For regions like Colorado, where temperature swings and sudden storms are common, investing in a high-quality glass greenhouse can make a significant difference in both durability and growing success.

How This Modern Greenhouse Performs in Colorado Weather

Colorado presents unique challenges such as late spring frosts, intense sun exposure, hailstorms, and rapid temperature changes.

This modern greenhouse is specifically suited to handle those conditions:

• Tempered glass panels resist impact from hail
• Reinforced framing supports snow loads without sagging
• Ventilation systems prevent overheating during high-altitude summer days
• The enclosed glass structure helps retain warmth overnight, reducing temperature swings common in Colorado climates

Combined with over 300 days of sunshine per year, a well-built modern greenhouse allows you to extend your growing season significantly, starting earlier in spring and continuing well into fall.

 

Best Plants to Grow in a Modern Greenhouse

With excellent light exposure and controlled ventilation, this greenhouse supports a wide variety of plants:

Year-round crops

• Leafy greens (spinach, kale, lettuce)
• Herbs (basil, parsley, cilantro)
• Microgreens

Extended-season vegetables

• Tomatoes
• Peppers
• Cucumbers
• Squash

Specialty plants

• Citrus trees
• Tropical plants
• Succulents
• Climbing flowers and ornamentals

A high-quality backyard greenhouse gives you the flexibility to grow both food and decorative plants in one optimized environment.

 

Cost of a Modern Greenhouse: What to Expect

Pricing for a glass greenhouse can vary depending on size, materials, and engineering quality.

Premium models like Janssens typically cost more upfront than entry-level kits,  but they offer significantly better durability, weather resistance, and long-term value.

Factors that affect cost include:

• Size and square footage
• Type of glazing (glass vs polycarbonate)
• Frame strength and materials
• Ventilation and automation features
• Installation and delivery

For homeowners planning long-term use, investing in a well-built lean-to greenhouse often results in lower maintenance costs and better performance over time.

 

Why Choose a Janssens Modern Greenhouse?

Janssens has been manufacturing premium greenhouses in Belgium for decades, known for precision engineering and high-quality materials.

The Modern series reflects that expertise, combining durable aluminum construction with tempered safety glass to create a structure built for serious growers.

At South Table Sheds, you’re purchasing from an authorized Janssens dealer, which means:

• Full manufacturer warranty coverage
• Guaranteed authentic products
• Access to expert support before and after purchase

Shipping is included across the continental United States, with curbside delivery and detailed assembly instructions provided.

For customers in the Denver area and surrounding regions, professional greenhouse installation is available to ensure your greenhouse is set up correctly and ready to perform.

 

Explore More Modern Greenhouses

Looking for a different size or configuration? Explore our full selection of glass greenhouse kits, and backyard growing solutions to find the perfect fit for your space.

Features

Push Open Window Window is hinged at the top.
Automatic Roof Opener When temperature falls a heavy spring pulls the window closed. No electricity needed!
Manual Roof Opener Manual opener that works like a large threaded screw
Double Hinged Doors

Specifications

Glazing: 4mm tempered glass panes
Frame: 17 gauge tubular aluminum extrusions
               heavy duty roof extrusions

Colors: Black

	Small Modern M23 (10'x 15')	Medium Modern M34 (10' x 15')	Retro Royal Victorian VI 46 (13' x 20')
Area	79 sq. ft.	150 sq. ft.	200 sq. ft.
Length	10'2''	15'	19'11''
Width	7'9''	10'2''	10'2''
Peak Height	8'10''	9'7''	9'7''
Sidewall Height	6'8''	6'8''	6'8''
Panels Long	4 (length) 3 (width)	6 (length) 4 (width)	8 (length) 4 (width)
Roof Pitch	15 degrees	15 degrees	15 degrees
Doors	1 set of double hinged doors	1 set of double hinged doors	1 set of double hinged doors
Frame Color	Black	Black	Black
Windows	2 Roof Vents 2 Push Out Side Windows 1 Louvre Window	2 Roof Vents 2 Push Open Side Window 2 Louvre Window	2 Roof Vents 2 Push Open Side Window 2 Louvre Window
Openers	1 Automatic (Roof) 1 Spindle (Roof) 1 manual (Louvre)	2 Automatic (Roof) 2 Spindle (Roof) 1 manual (Louvre)	2 Automatic (Roof) 2 Spindle (Roof) 2 manual (Louvre)
Glazing	4mm tempered glass panes	4mm tempered glass panes	4mm tempered safety glass
Materials	Aluminum frame & 4mm tempered glass	Aluminum frame & 4mm tempered glass	Aluminum frame & 4mm tempered glass
Overlap	N/A	4 cm overlapped glass panels on the roof	4 cm overlapped glass panels on the roof

 

 

Shipping and Delivery

Shipping

• Free Shipping in Continental US. 
• Greenhouse ships on 2 pallets and 2 long boxes

Delivery

• CURBSIDE DELIVERY. 
• All our deliveries are trucks with a liftgate.  When needed we can request a flatbed/forklift but often not necessary.  
• The carrier will call the customer for a delivery appointment when it reaches the destination terminal.
• The customer should be there to receive the delivery and notify us if there is any damage. 
• Do not refuse deliveries – we will send replacement parts. 
• Let us know asap if you do see damage. It will be quicker for us to send replacement parts.

Assembly

• The greenhouse kit comes with an assembly guide.
• South Table Sheds can recommend names/phone numbers of assembly technicians.
• South Table Sheds can be hired for assembly in the Denver, CO area. Please visit our page or contact us 720-656-7313
• Level of Effort
  • Installation requires two people minimum.
  • Skilled handyman, skilled homeowner, or assembly technician recommended

 

Assembly Instructions

Assembly Videos

 

Warranty

This product carries a limited warranty, which covers the following:

 

·        Aluminum frame and stainless steel hardware (up to 15 years from date of purchase)

·        Defects in material and workmanship when properly assembled using only manufacturer’s original equipment parts in accordance with manufacturer’s assembly instructions (up to 10 years from date of purchase)

 

Exclusions:

 

The warranty does NOT cover the following components, for which replacement parts may be provided at a reasonable cost:

 

• Tempered glass glazing
• Operating parts (such as pistons in automatic window openers)
• Other accessories provided with the greenhouse which are breakable in ordinary use.

 

The warranty does NOT cover damage resulting from any of the following:

 

• Excessive loads placed on the packed product and/or parts
• Glazing breakage caused by large hail, rocks or other projectiles (including rocks thrown by a lawnmower)
• Use of force, incorrect handling, or inappropriate use, neglectful use or assembly or maintenance, commercial use or use other than for personal or household purposes
• Alteration, painting, connecting, gluing, sealing or assembly not in accordance with the manufacturer’s instructions
• Extreme storms, wind, flood, fire, overaccumulation of snow load, or other extreme weather conditions.

 

Snow Load Advisory:

 

Customers are expected to regularly clear snow accumulation from the roof of their greenhouse as overaccumulation may crush the structure.  This type of damage is not covered under this warranty.

 

Commencement and Transferability

 

This warranty commences from the date of purchase and is non-transferable. A dated proof-of-purchase must be presented upon request. Customers are advised to keep this product warranty and proof of purchase in a secure place as they will be needed to process any claims.

 

 

 

Claims Process:

 

Address your claim to the customer service department by phone or email. A photograph or sample of the defective part(s) may be required to expedite the resolution process. If needed, the customer will allow the manufacturer or its representative to access and/or examine the greenhouse and its parts at the original service location. After a claim has been settled the guarantee will continue to run to its original expiry date (the original date of purchase). Exaco will repair or replace the product at our discretion.

 

Customer Satisfaction:

 

Ultimately, we strive to make every customer happy. We will do our utmost to resolve any warranty related issues in a manner satisfactory to the customer. 

 

Refund and Damage Policy

Refund

• We do not provide for or allow for "Buyer's Remorse" 
• We only give full credit for product received in re-sellable condition. It is assumed that no greenhouse arrives back in a re-sellable condition (based on practical experience) at a minimum most if not all packaging has to be replaced - and all to often some parts are damaged - as a result we have a minimum restocking charge of 20% for all our greenhouses - but if product is damaged - cost of damaged parts will be subtracted from the refund

 

Damage

Customers are required to accept delivery of all packages, even if a box arrives damaged. Any visible damage must be noted on the Bill of Lading at the time of delivery and reported to us promptly.

• Small Items (UPS & FedEx Shipments): If an item is damaged, customers should contact us and we will immediately send a replacement part.
• Greenhouses: Customers should take digital photos of any damage (if possible) and email them to us for review. Based on our assessment, we will either:

• • Send replacement parts immediately
  • Suggest an easy repair (minor damage to aluminum greenhouse parts is often fixable with basic tools, like pliers)
  • Offer direct compensation for cosmetic damage (typically $100 for RIGA or Victorian Greenhouses)
  • Fully replace parts with structural damage

We are committed to making sure every customer receives a high-quality product and the support they need for any issues.