Model # Mont-20-BK

Internet #203192075

Monticello 8 ft. x 20 ft. Black Greenhouse


8 ft. x 20 ft. Black Greenhouse

$394999 /each
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Product Overview

Not all greenhouses are built the same and the Monticello line of greenhouses by Riverstone Industries proves this to be true. The Monticello is applying good old American ingenuity to make the best product for our customers and help to elevate the industry standards of all greenhouses. Constructed from the highest quality extruded aluminum (US grade - not the thinner and more brittle foreign aluminum) and electrostatically painted Black (guaranteed to contain 0.0% lead), our greenhouse uses on average more than 85 lbs. more aluminum than the average imported greenhouse. Why is this important. The weaker the framework the less snow the greenhouse can hold in the winter time before collapsing on itself also the easier it will be get damages in wind. While most hobby greenhouses on the market us less expensive thinner walls and roofing materials (the crystal clear walls are as thin as 0.2 mm), the Monticello uses professional grade 8 mm twin wall polycarbonate. This is the same thickness as used in the commercial greenhouses. The twin wall polycarbonate acts as a double pain window keeping cooler air in during warm months and insulating the greenhouse from cold air in the wintertime. This not only makes the Monticello more efficient to grow in for a longer period of time than other greenhouses but it also adds to the efficiency of growing, cutting down electric bills for those who choose to grow year round.

  • Heavy duty extruded aluminum frame construction finished with electro statically applied black paint for long life
  • High impact, UV stable 8 mm commercial grade twin wall polycarbonate walls and roof construction
  • 1200 cu. ft. of space, plenty of space to grow your plants and vegetables
  • Through a combination of using superior materials that are more rigid and creating interchangeable parts in our design the Monticello takes the average gardener 10-12 hours to assemble the 8 ft. x 20 ft. greenhouse while using much fewer parts, this does not include the base prep work needed, which includes leveling the ground
  • 4 automatic opener roof vents (2 ft. x 2 ft.) opens and closes based on interior temperature to help prevent plant wilting and dry out
  • Integrated flush base design allows for lower than normal door threshold
  • A-frame roof design to optimize heat disbursement along with roof joist supports that double as hanging plant rods
  • Hinged lockable double doors
  • Greenhouse dimensions: 8.1 ft. W x 20.4 ft. L x 7.6 ft. which includes thoughtfully appointed structure including built in dual rain water collection system gutters
  • Solid commercial grade aluminum along with polycarbonate walls and roof construction assures no rust to the greenhouse
  • 10-year limited warranty on the entire greenhouse the strongest in the industry
  • Expandable can be expanded by using the mont-4-AL expansion kit which allows your greenhouse to grow as your needs do
  • Efficient average cost to run greenhouse year round ranges from $175 - $225
  • New patent pending twist and lock single bolt (makes assembly quicker and easier over prior version) (new for 2014)
  • Please note - allow for a full weekend to fully assemble (ground prep included), 2 people suggested for assembly, manual is fully illustrated

Info & Guides

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Approximate Depth (ft.)
Approximate Greenhouse Depth (ft.)
Approximate Greenhouse Height (ft.)
Approximate Greenhouse Width (ft.)
Approximate Width (ft.)
Assembled Depth (in.)
249 in
Assembled Height (in.)
90 in
Assembled Width (in.)
97.5 in
Door Opening Height (In.)
Door Opening Width (In.)
Exact Width x Depth
8 ft 1.5 in x 20 ft 9 in


Assembly Required
Floor Options
Without Floor
Frame Color Family
Greenhouse Features
Door latch,Lockable door/gate latch
Installation Available
Maximum Roof Load (lb./ sq. ft.)
Maximum Wind Resistance (mph)
Number of Doors
Number of Vent Openings
Product Weight (lb.)
Storage Capacity (cu. ft.)

Warranty / Certifications

Manufacturer Warranty
Limited 10 Year

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Customer Questions & Answers

With no supporting beams inside, I'm concerned about the 8 x 20 ft greenhouse collapsing in heavy winds.

Asked by: Tom
My Greenhouse is 2 years Old now. Last Week in Dallas we had 60-70 mile wind and Egg size Hail. The insurance company totaled my Roof on my Home. It was only 3 years Old and was The best money can Buy. It only did damage to two of my panels and only went through the first layer. The Ins Co Did not pay for the Greenhouse. But I made some important changes to the Construction of the House. First do not use 2x4 for the foundation. In The picture you can see that I used 4x8 in .4 CCA(ground contact) Beams from Home Depot this is very important. It gives you room to get it very tight. and makes it EXTRA Strong. As you can see I set the beams on 4x8x16 Concrete blocks then when it was complete we set a form 4 in away from the 2x8 beam and poured concrete in the space with the Tie down screws in the concrete. FYI before I retired I owned one of the Largest commercial Greenhouse's in Texas. I have built over one Million Sq Ft of Greenhouses.
Answered by: rustylwb
Date published: 2017-06-15

I just read the answers to my questions sorry about that. One additional question. Is there a way to put a sun screen over the top?

Asked by: rdp50
Easy Put it on the outside. To protect the UVC and keep the house Cooler. Buy at Home Depot 6ft x 20-25 69% shade in several colors. This is White & Black. Mt HD has stopped selling the Clamps but the Other Store does.
Answered by: rustylwb
Date published: 2016-05-14

What guage and material is used for wall and roof frames?

I'm looking at another g'house whose walls and roof frames are 18 or 20 gauge G-90 galvanized steel. How does this one compare?
Asked by: 1234
This greenhouse does not use steel. Instead this greenhouse is constructed of heavy0duty aluminum.
Answered by: CommunityAnswer
Date published: 2015-09-20

how much snow load will this structure support? How much wind can this structure withstand?RDP50

Asked by: rdp50
  • y_2017, m_7, d_17, h_13CST
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Customer Reviews

8 ft. x 20 ft. Black Greenhouse is rated 4.0 out of 5 by 1.
Rated 4 out of 5 by from Great Greenhouse Bought this greenhouse last fall.I used a different footing because I wanted more strength. used 4x8 treated timber. From HD. This gave me the assurance that I had a lifetime footing and I could line up the Base plate on the timbers. I set the beam's on 8x16 concrete blocks and then I set a form up a few inches away and poured concrete under the Beam. The greenhouse went together smooth except for an Ice Store that came to Dallas. The plan's said to do the work in one day. It took me a couple of week's.I have included pictures of the construction. The house is strong and has had 60+ wind but without the the smallest movement. The door will have to be reengineered. I have talked to the factory about all of the questions that came up. They could not be nicer people. The manager even gave me his home phone # if I needed to call after hours. I grew my first crop this winter. I would not consider any other house. I did a lot of research before the purchase. And I'm also a retired Pro Grower. You can buy this product without worry about problems. Sorry no pictures. As usual the site doesn't work.
Date published: 2014-03-30
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