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Hoklartherm RIGA Greenhouses (Multiple Sizes Available)

The RIGA is truly a greenhouse by the European definition of a greenhouse - designed to be used to grow fresh vegetables, herbs and flowers in the middle of winter. While other so called “greenhouses” using less than 8 mm twin-wall polycarbonate, are considered to be Season Extenders, to be used when only a slight night frost might be expected during the spring or fall season. At best they can only be used to house established plants during the winter season.
The RIGA is truly a greenhouse by the European definition - designed to be used to grow fresh vegetables, herbs and flowers in the middle of winter. While other so called “greenhouses” using less than 8 mm twin-wall polycarbonate, are considered to be Season Extenders, to be used when only a slight night frost might be expected during the spring or fall season. At best they can only be used to house established plants during the winter season.
New Animated Video Assembly Instructions for RIGA Greenhouse    -Click Here-

Why Choose RIGA?

  • The RIGA Greenhouse is designed, engineered, and manufactured in Germany by Hoklartherm, a leading manufacturer of commercial and hobby greenhouses, sunrooms, pavillions, pool covers, home additions, and commercial building, with 28 years experience.
  • With a combination of strong materials and durable hardware, the Riga Greenhouse is by far the strongest greenhouse under $5,000.
  • The Riga Greenhouse offers more window and door ventilation than another units it is class.
  • The polycarbonate glazing on the Riga Greenhouse is German made and believed to be of superior quality then the much more common Polygal or GE glazing.
  • The Riga Greenhouse comes with an optional two layer shelving system with removable shelf inserts. This allows for tall plants (beans, tomatoes etc.).
  • The optional 6" high base frame (which is often used to increase the height of the roof), is 2-3" higher than most competitors.
  • One major advantage of the Riga's construction method is that the frame profiles are permanently attached to each other, and won't come loose over time due to wind pressures.
  • German engineering - guaranteed top quality!
  • Optional Shelving: Seedtray/Bench shelf and top shelf are available with strong diagonal support braces – can hold a 160 pound man! White twin-wall polycarbonate shelf inserts can be removed to allow for tall plants such as tomatoes or beans or to allow insertion of heavy-duty seed trays. This greenhouse can flex to your gardening needs throughout the year.
  • The RIGA Greenhouse is attractive and beautiful to look at – fits well in to an upscale garden setting
    Buying a greenhouse is like buying a car, they vary in cost from cheap to very expensive, the RIGA is a class similar to a Volkswagen/Volvo – stronger, more durable and better insulated, and offers many more features than the better selling brands.
  • The RIGA Greenhouse offers the minimum insulation needed to grow plant year-round – others using less insulation cost too much to heat.
  • RIGA Greenhouse units are available in 5 sizes
  • We recommend you buy one size bigger than you planned.
  • Come with DVD and written Assembly Instructions
  • Made in Germany

Additional Images and Information

Click to display more information and larger image

Options and Accessories

  • VIEW RIGA GREENHOUSE ACCESSORIES
  • Base frame - 6” high: highly recommended. Attaches to the bottom of the greenhouse. Usually sits in the ground but can also be mounted on top of a wood, concrete or brick frame/wall to provide 5” of additional inside height.
  • Top shelving: Shelving with strong white twin-wall polycarbonate inserts (removable) – 10” deep.
  • Regular height shelving: Shelving with strong white twin-wall polycarbonate inserts (removable) - 24” deep
  • Two options: twin-wall polycarbonate inserts (flat), or heavy-duty seed trays – to make starting seeds and transplanting easier.
  • Additional Roof Windows with Automatic Openers: recommended in areas where temperatures will reach over 95º F when still using the greenhouse.
    View a roof opener demonstration/installation video.
    We also recommend you use shade cloth as well, especially during the summer.
  • Adjustable Metal Hooks: Set of 5 metal hooks. These are great for hanging lights, fans and flower baskets (heavier items)
  • Plastic hanger: Set of 10 hangers: These snap into the groves in the aluminum profiles (frame) and are used to attach twine/rope to, to support growth of tall plants (I.e. Tomatoes or beans etc.)

Specifications Details

  • Extremely heavy duty construction
  • First-class insulation: R or K-value 3.0
  • Warranty: Polycarbonate: 10 years; Frame: 15 years
  • Heavy duty Dutch Barn Door with keyed lock: 30" wide x 72" tall. 72” tall narrow unit /79” tall wide unit
  • Oversized Rear Wall window: 30" wide x 42" high with adjustment arm
  • Roof Window(s): 40" w x 24" d; with Automatic Window Opener
  • 8 MM UV coated twin wall
    polyvcarbonate over main body
  • 10 MM twin wall polycarbonate in front & back walls for extra strength
  • Inside walking height: 6’1” near shelves, 6’11” in the middle of the narrow unit and 7’6” high for a wide unit.
  • Assembly time: 2 people, 1 full day (3 makes it easier and reduces it to 6-8 hours (excluding any shelves)
RIGA 2S RETAIL AT: $2799.00
RIGA 2S FOUNDATION FRAME RETAIL AT: $349.00
RIGA 2S TOP SHELF RETAIL AT: $170.00
RIGA 2S BOTTOM SHELF RETAIL AT: $209.00
RIGA 3 RETAIL AT: $3499.00
RIGA 3 FOUNDATION FRAME RETAIL AT: $499.00
RIGA 3 TOP SHELF RETAIL AT: $219.00
RIGA 3 BOTTOM SHELF RETAIL AT: $299.00
RIGA 3S RETAIL AT: $3399.00
RIGA 3S FOUNDATION FRAME RETAIL AT: $425.00
RIGA 3S TOP SHELF RETAIL AT: $219.00
RIGA 3S BOTTOM SHELF RETAIL AT: $299.00
RIGA 4 RETAIL AT: $4599.00
RIGA 4 FOUNDATION FRAME RETAIL AT: $640.00
RIGA 4 TOP SHELF RETAIL AT: $299.00
RIGA 4 BOTTOM SHELF RETAIL AT: $389.00
RIGA 4S RETAIL AT: $4199.00
RIGA 4S FOUNDATION FRAME RETAIL AT: $560.00
RIGA 4S TOP SHELF RETAIL AT: $299.00
RIGA 4S BOTTOM SHELF RETAIL AT: $389.00
RIGA 5 RETAIL AT: $5199.00
RIGA 5 FOUNDATION FRAME RETAIL AT: $699.00
RIGA 5 TOP SHELF RETAIL AT: $359.00
RIGA 5 BOTTOM SHELF RETAIL AT: $499.00
ADDITIONAL ROOF WINDOW RETAIL AT: $230.00
AUTOMATIC WINDOW OPENER RETAIL AT: $75.00
REPLACEMENT PISTON FOR AUTOMATIC WINDOW OPENER RETAIL AT: $30.00
RIGA ASSEMBLY FACILITATION KIT RETAIL AT: $99.99
ROOF WINDOW RESTRAINT 2 15" SYSTEM RETAIL AT: $15.99
ROOF WINDOW RESTRAINT 4 15" SYSTEM RETAIL AT: $29.99
ROOF WINDOW RESTRAINT 8 15" SYSTEM RETAIL AT: $59.99
ADJUSTABLE METAL HOOKS RETAIL AT: $15.99
PLASTIC HOOKS RETAIL AT: $15.99
HEAVY DUTY SEED TRAYS RETAIL AT: $24.99
MISTING SYSTEM RETAIL AT: $160.00
DOOR EXTENSION KIT FOR 2S, 3S, 4S RAISES GREENHOUSE 20" RETAIL AT: $250.00
DOOR EXTENSION KIT FOR 3, 4, 5, RAISES GREENHOUSE 20" RETAIL AT: $299.00
DOOR EXTENSION KIT FOR XL RAISES GREENHOUSE 20" RETAIL AT: $699.00

This is a great German product!

I spent 10 weekends to build this green home use for my wife to grow orchid in Ontario Canada.

Yes! I recommend this product.

Galliano | 11/30/2016


I want to compliment the company on the precision and fit of this unit.

My name is Claude Keefer and I helped the Elmwood Ag classes and Teacher Ms. Lafollette with the assembly of the Riga V Greenhouse that they purchased. I spoke with Andrew on Saturday 5 Dec 15 in preparation for beginning the assembly. As you recall, we build the unit offsite and transported it to the school last Friday. Photos are attached.

I want to compliment the company on the precision and fit of this unit. I was very impressed with the total system and the fit and finish were outstanding. I honestly did not expect everything to line up and fit the way it did. Every bolt hole lined up with others and spacing around the doors and windows was quite good. I really like the "bagging" of parts with labels for doors, windows etc. That made searching for parts less of a problem. Nylon ends for the top and bottom of the side ribs was very valuable.

We we fortunate to have a place to build the unit on a flat surface and we did not rush. Unpacking, preparing the base unit and the lifting platform took about 6-8 hours. With about 5 boys we assembled the end walls and the main body in 8 hours. Another 6-8 hours were spend with braces, window/door assembly and seals/silicone. Finally, we loaded the unit on a flat bed, hauled it to town (4miles) and put it into position on a prepared flat pad. The inside was filled with pea gravel and the outside was backfilled. 8 hours.

The engineering is great! My only recommendation on the manual is to be sure that all the photos indicate whether you are looking from the outside or the inside.

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Yes! I recommend this product.

Claude Keefer | 12/15/2015


Excellent and Tough in Broken Arrow Oklahoma!

We bought our Riga IV greenhouse back in August of 2009 and we are so glad we did. Our Oklahoma weather includes temperature extremes, high winds, hail and tornadoes and our Riga greenhouse has survived it all nearly unscathed. Our home was damaged by a tornado in May of 2015 and even though our entire roof needed to be replaced on our main home, some siding needed to be replaced, and our garage door needed to be replaced on our main home, our Riga greenhouse was fine. We only needed to replace a couple of the auto-vents on the greenhouse that were bent from the wind during the tornado. I fully expected this greenhouse to be damaged by hail storms that we have experienced here since we purchased our Riga IV and it was not damaged by the hail either even though we had to make an insurance claim for hail damages on our main home. Because of the extreme weather we have here in Oklahoma we purchased the Riga model that has the foundation base frame to help secure it to the ground. We also topped off the foundation base frame with bricks for added weight ~ see photos. The people here at Exaco Trading Company are very helpful and friendly. We are extremely pleased with this greenhouse and since 2009 it is working wonderfully for us! :-D

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Yes! I recommend this product.

Wendy Sue | 12/4/2015


A joy to work in !!!

I am the horticulturist and garden manager for a large private estate located in Southern California. I grow organic vegetables for the estate and a nearby restaurant. Prior to acquiring the Riga III, I purchased my organic vegetable starts from a local grower. I was limited to the varieties that they chose to grow and had to deal with a lower level of quality than I wanted.

After doing a LOT of online research, I decided that the Riga was the greenhouse that I wanted. I felt that the price was more than reasonable for all of the features offered.

The ordering process and subsequent delivery was problem free. While the installation was somewhat challenging - with the aid of the video and the written instructions it was assembled by a team of three capable men in just over a day.

Our greenhouse sits on a poured concrete pad that we installed with a drain and an irrigation quick coupler. This makes it easy to water and to keep the greenhouse clean inside.

The Riga III is very roomy and I am able to have 32 flats of seedlings growing at the same time. The quality of my vegetable starts is amazing now! Seeds germinate in just a couple of days. The diffused light allows is perfect. I directly attribute the improved quality of the vegetables I am producing to the Riga III.

I don't have to deal with snow here in Southern California- but as my greenhouse is sited on top of a hill in full sun- I do deal with high summer temperatures and occasional high winds up to 60 mph. The Riga is the only greenhouse I found that has a back wall window. The cross ventilation that I get by keeping the top of the dutch door open and the back window open really helps with keeping my summer temps low which helps to keep both my vegetables and ME comfortable as I like to work in the greenhouse in the afternoons. The Riga has withstood the winds like a champ!

Of course, I didn't have to use my own money to pay for the greenhouse. My employer did that. But, I am so in love with this greenhouse that I am getting ready to buy one myself for my own backyard!

I highly recommend this greenhouse to anyone who wants a beautiful, functional, strong, easy maintenance, high quality greenhouse in which to grow beautiful plants of any type!

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Yes! I recommend this product.

Lydia | 10/14/2015


Great greenhouse! Great service!!!!

I asked a million questions to Andrew. I really researched this product. They answered all my questions and installed the Riga XL. I couldn't be happier with both the service and product. It's very rare you get this quality experience. The help I got in setting up the foundation to the greenhouse setup was amazing. Our greenhouse is even better than we imagined. We even purchased additional heaters and composting bins!

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Yes! I recommend this product.

ReidRo | 9/7/2015


Loved my first Riga so much I bought another!

I bought my first Riga III Greenhouse in January of 2014. This is a sturdy little greenhouse! Lots of great features for the price. I did lots of "shopping around" before I purchased a greenhouse and just kept coming back to the Riga. By the end of my first "growing season" I sadly realized I had not bought a big enough one. I was determined to have something larger for 2015 so I started shopping around again. I just kept coming back to wanting another Riga. I was sold on its features and how sturdy it was. I knew it would survive our extreme Nebraska weather - wind, hail, rain, wind, snow, ice, heat, wind, cold....and did I say wind? Yep, my Riga endured and stood up to all that weather its first year. So.....in February of 2015 I purchased another Riga III greenhouse. I bought one identical to my first one and butted the two together to make one greenhouse! I now have all the room I need! And my plan to put the two together worked out perfectly! We mounted the door on the second greenhouse so it swings IN instead of out. I can close off the second greenhouse if I don't have plants in it or don't want to heat it. I now have two automatic roof vents, a window on one end and the divided door on the other end - just like it was when they were single greenhouses. The greenhouses butted together with only about a half inch space between them. We cut silver flashing and screwed it on to the outside of the greenhouses thus "connecting" them and sealing out any air. We also added clear calk to help seal and adhere the flashing to the greenhouses. There is absolutely NO air that seeps into the greenhouses through this small space. My greenhouses are mounted on 4X4 treated timbers. I have dirt floors which I have covered in ground soybean mulch which helps keep heat in and also absorbs water. They are firmly mounted to the ground with those tie downs that screw in to the ground. This greenhouse is secure! Might not withstand a Nebraska tornado, but it has stood strong through some 40-50 MPH winds.

I am SO happy with my Riga greenhouse! I would recommend a Riga to anyone who is looking to buy a greenhouse. They are sturdy. I have no problem with keeping my Riga heated in the winter and cool in the spring/summer. And, like I said before, we have some pretty extreme weather here in Nebraska. You will not believe how quickly stuff germinates in this greenhouse. The conditions are perfect. My only advice would be to MAKE SURE you buy a big enough one the FIRST TIME!

And....when it comes to assembly...the video that comes with the greenhouse is your best friend. Watch it at least once before you even attempt assembly. We took a laptop to our assembly site and watched the video step by step as we put it together. This being said it really wasn't that hard to put together and ours went up fairly fast.

I just can't say enough how much I love my Riga greenhouse!

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Yes! I recommend this product.

Redmanhunter | 7/27/2015


Riga 4 thrives in harsh New England weather.

I've had this Riga 4 greenhouse for 5 years. On Cape Cod, we have very beautiful summers and falls but winters can be brutal. We are a little sand spit sticking out into the North Atlantic. For example, this past winter we had over 100" of snow and hurricane force winds for many days at a time. The Riga greenhouse never has failed in 5 winters like this. It is absolutely built to withstand hurricanes.

We use the greenhouse for seedling starts in the spring (starting around March 1) and then season extension in the fall from about October through January. We grow lettuce, spinach and micro greens in the fall and early winter. To regulate the warmth, we fill 3 large black plastic livestock watering troughs with water. They fit under the shelves on the north side of the greenhouse. The sun heats them up during the day and they give off their heat at night. This past winter they never froze inspire of many days of sub zero weather and cloud filled days. I am very happy with my Riga 4.

Yes! I recommend this product.

Jeff | 6/24/2015


Riga 3 is wonderful!

We live on the eastern side of the Sierras where the wind "blows the sun away." The winds come over the mountain and can be quite ferocious, on a regular basis, every year, and we have seen heavy, heavy snow. Our Riga has survived 100-mile-an-hour winds here and has gone through numerous windstorms without a problem until we had a 120-some mile an hour storm in January. Then the wind caught the door and broke the hinges. Now that I have the metal hinges for the door it should be fine. It has also nicely survived heavy snows here; the snow slides off the roof.

When we were looking online to find a greenhouse that would survive our climate, we ran across your website showing your husband standing straddling the peak, and we knew we had found what we were looking for. I can't remember what year we bought it, somewhere around 2007, and it has gone through everything nature could throw at it so far. I have put up garden-style lattice-work on steel poles on the windward side to help shield it somewhat from the wind, which has helped somewhat too.

Your product is truly a step above the rest. Other greenhouses in this area have not fared as well. I have even tried to steer people who were in the market to buy greenhouses to the Riga.

Again, thank you for your excellent product.

Yes! I recommend this product.

Rick | 5/14/2015


Just starting with our Riga Greenhouse..What a joy.

Our Greenhouse is on its way...Just spoke with Kim who was a wealth of information and interested in what we will be doing with our greenhouse here in Falmouth, MA.

As part of a community non-profit, Falmouth Together We Can Inc., we started a group called Well-Grounded; it is a Service Learning group that is made up of three teachers, English, science and woodshop; one community partner, an artist, about 15 students ranging in age fro 12 to 18 and the numerous business partners we have made over the past year.

We provide spring and fall clean-ups to the Senior Center in town, churches in the community, plant the annual flowers for Veterans Day, shovel snow for our seniors, design and maintain our school Memorial Garden, and study, grow and sell organic, GMO free seedlings...thus the greenhouse. Our community has been incredibley supportive. We have one native partner who donated the funds for this greenhouse and another anonymous donor who gave 10k dollars to support our students. So proud of the students, and the fun I have is beyond words! Thank you Kim for making this adventure even more incredible!

Stay tuned for pictures of set-up and completion.

Yes! I recommend this product.

Kathleen | 5/3/2015


Innovative and functional!

We purchased our greenhouse nine years ago and have been extremely happy with it ever since. The instructional DVD was invaluable in the construction of the greenhouse.

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Yes! I recommend this product.

Pmac1951 | 4/25/2015


Love my RIGA IV Greenhouse

We assembled my Riga IV greenhouse this fall so that I can start my vegetables much earlier in the spring. The result is not only practical but beautiful. I bought this style because I live at a high elevation where we get a lot of snow in the long winter. The ceiling windows opened and closed automatically from the start. Exaco provided outstanding support, from my many phone calls to the great coordination of the delivery truck. Their DVD provided very helpful insights into the assembly. I also appreciate many of the details provided by the German engineering of the design. I'm thrilled with my final greenhouse and would recommend it to any of my friends.

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Yes! I recommend this product.

MaryN888 | 3/15/2015


Very Sturdy Design.

We bought the Riga V 3 years ago and have been delighted with it. A 2014 Colorado golf ball sized hail storm demolished the roof on our house and out buildings but only left some small divets in the greenhouse . This is probably the best greenhouse on the market for a residential setting.

Yes! I recommend this product.

Mark | 3/6/2015


Very pleased with our Riga V.

Our Riga V is mounted on a stem wall. We grow vegetables year round in Northern New Mexico at 7800 ft. Retrofitted the doors for summer with screens to maintain temperatures. So great to have fresh tomatoes in the winter!

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Yes! I recommend this product.

Dr D | 3/1/2015


Great greenhouse for amateur enthusiast.

I bought this close to 3 years ago and love it. It was fun to put together and I have since added electricity so I can run fans, heat (only a little on coldest nights), and grow light. I use it to winter over plants as well as grow seedlings. I'm in it almost every day.

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Yes! I recommend this product.

Joe F | 2/22/2015


Riga 4 is a real winner at 3500 feet in Canada.

We bought a Riga 4 in the late fall of 2014. By the time it arrived the ground was frozen and snow covered so my husband and some neighbors assembled it in our garage. When the snow left early this year we got a bunch of friends to help move it to a pad in the garden and by March 4th I had planted lots of cold loving plants directly in the ground. Between the ground-planted crops and indoor-started plants being hardened off, the greenhouse has been continuously busy and productive ever since. COMPLETELY WITHOUT SUPPLEMENTAL HEAT, by mid-April we began harvesting loads of spinach, lettuce, green onions, radishes and bok choy until we began replacing these early veggies with heat lovers like tomatoes, peppers and muskmelon.There were a few nights early on where we had a borderline frost but no damage on the cool climate plants and now (June 7th) the trick will be to prevent overheating. I have had home made greenhouses before but NOTHING has matched the Riga performance. I am already harvesting peppers. This is all happening on a north-east facing slope at 3500 feet elevation in the Canadian Rockies. Amazing!

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Yes! I recommend this product.

Bonnie | 2/20/2015


I LOVE this greenhouse.

I bought this greenhouse in 2009 from Exaco and have had wonderful success with it. I am growing vegetables, herbs and flowers. It is SO well built and holds up in the big winds and snow that I get at 6,000 feet in the Southern California mountains. I also love the ventilation in the greenhouse as we can get 80-90 degree temperatures in the summer. During the summer I leave the top of the dutch door open along with the window on the opposite side of the greenhouse. This, together with the automatic windows on the top of the greenhouse, allows me to grow in the heat of summer. I also love the shelving on one side o the greenhouse with the panels that I can take out depending on how tall the plants under the shelf grow. I highly recommend this greenhouse.

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Yes! I recommend this product.

Karen | 2/7/2015


Structural Integrity.

We purchased a Riga 8 and are pleased with the quality and strength of the product. Assembly was well documented. Customer service was exceptional. Exaco is a first class operation. The Riga system is perfect for our windy location.

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Yes! I recommend this product.

Merric | 1/14/2015


How do I install a new cylinder in the automatic roof vent opener? It did not come with instructions.

Carol | 9/18/2016

Hello, Thanks for visiting our site! Here are some steps for installing your new piston: 1. Remove old piston by removing cotter pin from the top and unscrewing it counter clock wise. 2. Install new piston by doing the reverse of removal of old.

Here is a video on the automatic opener in a Riga Greenhouse. Fast forward to the 33 second mark.

If you need anything else please let us know.

Thanks, Customer Support


I am looking to purchase the Riga 3 and want to use 4 x 4 timbers along with the foundation frame to secure the unit. What dimensions should I lay the timbers so that the Riga foundation frame can be anchored onto the center of the timbers? Thanks.

Jon S | 8/28/2016

Hello, Thanks for visiting the website! The Riga Foundation Frame is meant to be buried in the soil. You can mount it to the timbers to gain height though. The base dimensions as per the Riga manual are: Riga III 116 9/16 Inches Wide x 126 3/4 Inches Long

All dimensions can be found in the assembly instructions on the Riga page of our website.

I would also suggest cedar timbers. Sometimes the chemicals used in pressure treated wood can have a reaction with aluminum causing it to corrode.

If you need anything else let us know.

Thanks, Customer Support


In ground growing? A unit that could be portable within a larger garden for various in ground crops?

Vicki | 7/17/2016

Hello, You can grow in the ground inside of a Riga Greenhouse or build some planter boxes and grow in them. We have cold frames that could be moved around to various crops. Have a look at the cold frame section of our website. If you have any more questions please don't hesitate to give us a call or email. 877-760-8500 customerservice@exaco.com

Thanks, Customer Support


I have a Riga IV and would like to be able to have more hanging plants. I was looking at hanging a pole from the ribs to do this. How much weight would I be able to have on the pole?

Cathie | 7/10/2016

Hello, Congrats on being a Riga owner. Yes you can hang a pole from the curved profiles. The greenhouse is very sturdy but we recommend that you keep it under 150lbs for each side and make sure its distributed evenly. Note the position of the curves from the outside and if it appears that they are starting to sag or bend down, reduce the weight hanging from them.

Thanks, Customer Support

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