Grandio Summit 12x28 Greenhouse Kit 10mm Twin Wall Polycarbonate

Is the Summit 12x28 Greenhouse Kit the Solution for Your Year-round Gardening Needs?

Now accepting backorders — stock expected to arrive by mid to late December!

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The Grandio Summit 12x28 Greenhouse Kit provides a spacious, durable and weather-resistant structure designed for gardeners who want a reliable space to grow plants throughout the year. With its barn style roof, reinforced aluminum frame and insulated 10 mm twin wall polycarbonate panels, this greenhouse offers long lasting protection, excellent climate control and an attractive look that enhances any outdoor space. Whether you are a beginner or an experienced grower, the Summit 12x28 gives you the space and strength needed for productive, all season gardening.

Why Choose the Summit 12x28 Greenhouse Kit?

Built to Handle Harsh Conditions

The Summit 12x28 greenhouse features a strong 1.6 mm powder coated aluminum frame reinforced with cross roof trusses and cross corner bracing. Combined with durable 10 mm UV protected twin wall polycarbonate panels, the structure is engineered to maintain temperature stability and stand strong through changing weather throughout the year.

Excellent Winter Insulation

The 10 mm twin wall panels provide an R value of 1.89 and a U value of 0.53, offering strong insulation that helps retain warmth, reduce heat loss and support winter growing. This makes the Summit an excellent choice for gardeners in cold climates or anyone who wants to extend their growing season.

Easy Entry and Healthy Ventilation

Sliding double doors are top hung to prevent jamming and glide smoothly thanks to durable nylon wheels. The lockable handles add extra security.
With fourteen roof vents, you get excellent airflow and humidity control, both essential for healthy plants year round.

Packed With Helpful Features

The Summit 12x28 comes fully equipped with a rain gutter system, drain kit, extreme snow load kit and a flat mount anchor kit for stability. These features support drainage, protect against heavy snow and help secure the greenhouse in harsh conditions. This thoughtful setup makes the Summit ready for long lasting performance as soon as it is assembled.

BENEFITS

• Durable Build for Tough Conditions: Constructed from a sturdy 1.6mm profile aluminum frame, this greenhouse is built to handle harsh weather, ensuring that your plants stay safe. Its rugged design makes it highly reliable, allowing you to enjoy gardening all year long, regardless of the climate.

• Keeps Your Plants Warm All Year: The 10mm twin-wall polycarbonate panels offer excellent insulation, with an R-value of 1.89* and a heat loss U-value of 0.53, helping to retain warmth and reduce energy costs. This makes the Summit an ideal greenhouse for gardeners looking to extend their growing season into cooler months.

• Easy to Use and Access: With sliding double doors that move smoothly and don’t get stuck, getting in and out of the greenhouse is hassle-free. Made with durable materials, the doors also have lockable handles for security, and fourteen roof windows let fresh air circulate to keep your plants healthy.

• Comes with Extra Features: Equipped with rain gutters, a drain kit, a snow load kit, and anchors, this greenhouse is ready for any kind of weather. These features make it an ideal choice for beginners and experienced gardeners alike who want a dependable greenhouse.

The Summit 12x28 Greenhouse Kit combines durability, warmth, and ease of use, giving you a large, protected space for growing plants throughout the year.

SPECIFICATIONS

DIMENSIONS

Actual Size: 12' W x 28' L x 9.25' H

Door Size: 41.5" W x 85" H

GRANDIO GREENHOUSE MATERIALS VS OTHER BRANDS

WHAT'S INCLUDED IN THE PACKAGE?

Basic Kit Includes:

• 10mm Twin-Wall Panels
• (14) Roof Windows
• Rain Gutters
• Drain Kit
• Extreme Snow Load Kit
• Flat Mount Anchor Kit

Optional Premium Kit Includes:

• 10mm Twin-Wall Panels
• (14) Roof Window
• Rain Gutters
• Base Kit
• Drain Kit
• Extreme Snow Load Kit
• Flat Mount Anchor Kit
• (14) Auto Roof Vent Openers
• (2) Pack of 10 Plant Hangers
• (1) Trellis Kit
• (1) Drip Kit
• (2) 8 oz. Brillianize Cleaner

ASSEMBLY VIDEO

GRANDIO SUMMIT #1 BASE INSTALLATION

GRANDIO SUMMIT #2 ASSEMBLY INSTRUCTION

GRANDIO SUMMIT #3 PARTS LIST

Compare Grandio Greenhouse Models

Compare with Other Greenhouse Brands

Optional Accessories

	Drain Kit - Downspout for Grandio Greenhouse Gutter Systems, designed for installation at each of the four corners of the greenhouse. It’s made to be installed directly into the aluminum frame and gutter of the greenhouse. The easy-to-install downspout drain kit includes (4) 20mm black pipes, (4) gutter attachment gaskets, and (4) side wall brackets with screws. One kit has everything needed to add downspouts to a Grandio Greenhouse.
	Automatic Roof Vent Opener - Automatically opens and closes the roof vent window based on temperature changes. The opener contains a metal cylinder with a mineral that expands when heated, pushing a piston to open the vent. When the temperature cools, the mineral contracts, and a spring closes the vent, resetting the piston. The vent opens and closes gradually, allowing the right amount of airflow for cooling.
	Auto Louver Window Opener - Automatically opens and closes the louver window as the temperature changes. The opener has a metal cylinder with a mineral that expands when heated, pushing a piston to open the vent. As the temperature cools, the mineral contracts, and a spring closes the vent and resets the piston. The vent opens and closes gradually, providing just the right amount of airflow for cooling. This Auto Louver Opener attaches to the left side of your louver window.
	Louver Window - add more ventilation to your greenhouse. Louver window frame comes powder coated in green, with 6mm twin wall polycarbonate panels.
	The Drip Irrigation Watering Kit - is a water-efficient system designed for shrubs, trees, flowers, and bushes, covering up to 150 square feet with easy expandability. It's a DIY-friendly installation with no gluing required, using high-quality UV-resistant materials. The kit includes 24 pressure-compensating drippers (20 at 1 GPH, 2 at 2 GPH, and 2 at 4 GPH) for consistent water delivery to plant roots. A backflow preventer ensures water safety by preventing siphoning into the main supply.
	Moisture Control Kit - featuring Anti Dust Tape and Waterproof All-Weather Silicone Caulk, protects your Grandio Greenhouse from insects, dirt, mold, and algae. The tape's 45-micron filters allow condensation to escape while preventing algae and mold growth with a fungicidal coating. Combined with the silicone caulk, this kit ensures long-lasting protection and maintains the greenhouse's pristine condition.
	Shade Net - are essential for regulating greenhouse temperatures, especially during sunny spring, autumn, and summer days. Designed to reduce intense sunlight by 50%, they help keep your greenhouse cooler and prevent overheating.
	Plant Hangers - These versatile plastic hangers are designed for greenhouse use, supporting shade cloths, hanging baskets with quarter-inch hooks, and stringing taller plants or vines. Easy to install, they simply twist into the roof rafter channels.

SHIPPING INFO

Lead Time is 1 to 2 days. Orders typically arrive within 1-7 business days, depending on your location:

• West: 2-4 days
• Northwest: 1-3 days
• Southwest: 3-5 days
• Midwest: 4-6 days
• East: 5-7 days

Note: Delivery times are estimates and exclude order processing time. Delays may occur due to weather or carrier issues.

FAQ