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Riga 5 Greenhouse (10X18)

Riga 5 Greenhouse (10X18)

Regular price $7,919.72
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Premium Kit

Hoklartherm Riga V Greenhouse (10X18)

The commercial-grade Riga 5 Greenhouse from Hoklartherm, the leading builder of premier greenhouses in Germany, is a beautiful addition to any garden. Its spacious 10X18 interior gives you space for anything you decide to grow, and many customers use it as an outdoor sunroom or even for a hot tub or indoor pool enclosure. Hoklartherm, are a leading manufacturer of commercial and hobby greenhouses, sunrooms, pavilions, pool covers, home additions, and commercial building, with 28 years of experience.

The Riga 5 is 9′ 8″ W x 17′ 6″ L x 7′ 7″ H and is designed to be used to grow fresh vegetables, herbs, and flowers year round. With a combination of strong materials and durable hardware, the Riga Greenhouse is by far the strongest greenhouse, and best greenhouse in the market for a residential setting.

The Hoklartherm Riga greenhouse is for the serious gardener with limited space, who want to grow vegetables year round. Its heavy-duty construction and twin polycarbonate wall allows a problem-free growing all year long. This gothic-arch greenhouse comes equipped with convenience features including automatic roof windows that open without using electricity. You can grow vegetables year-round, Retrofit the doors for summer with screens to maintain temperatures, and have fresh tomatoes in the winter!

The Riga Greenhouse offers more window and door ventilation than other units it is class. The polycarbonate glazing on the Riga Greenhouse is German made and believed to be of superior quality than the much more common Polygal or GE glazing.

Riga Greenhouse are grow plant year-round long greenhouse, not only a "season expander" greenhouse. While other so-called “greenhouses” using less than 8 mm twin-wall poly-carbonate, 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. This greenhouse will give you the flexibility you need to tend to your greenhouse garden all year round. It can also be used to simply extend your growing season if you choose not to utilize the year-round capabilities

With 8mm UV-coated glazing on the sides and 10mm in the front and back, the Riga greenhouse uses a thicker material that insulates better than a glass window in your house. The polycarbonate glazing on the Riga Greenhouse is German made and believed to be of superior quality than the much more common Polygal or GE glazing.

The "onion" shape provides no surface to snow or wind. Snow loads will just slide off the sides and severe winds blow over the greenhouse. The frame profiles are thicker or have a larger diameter than other greenhouses, which makes the construction stronger and Riga Greenhouse is by far the strongest greenhouse in its category

The large windows open and close automatically according to the temperature inside the greenhouse. Additionally, you can open the upper part of the Dutch barn-style door to provide great airflow. The door is wide enough to push a wheelbarrow into your Riga V greenhouse.

With its durability, attractive design, and spacious interior, the Hoklartherm Riga V Greenhouse is sure to become a showpiece for your family for many years to come.

Why Buy a Riga 5 Greenhouse?

  • Riga 5 Greenhouse has a special shape, which is designed to offer optimal headroom inside, but with enough slope on the outside so that heavy snow loads slide down and the severe wind blows right over

  • With German engineering and a special “onion” shape, this Riga greenhouse can withstand heavy snow and harsh wind, and it will look great doing it

  • Comes with a large Dutch barn-style door – with a key & lock

  • Offers more window and door ventilation than another unit in its class

  • Attractive and beautiful to look at – fits well into an upscale garden setting

  • The unique design of the Riga Greenhouse Kit has the best ratio between aluminum framing and polycarbonate panels, which allows for maximum light transmittance and less “moving” shade

  • Comes standard with an oversized rear-wall window for better ventilation

  • 10 mm twin-wall polycarbonate wall panels in the front and rear 8 mm UV-coated twin-wall polycarbonate over the main body

  • The optional 6” high foundation frame can be buried in a trench to easily and securely anchor the greenhouse. This is a great option if other anchoring methods, such as concrete, are not desired. Can Be Installed with or without a base

  • The RIGA 5 Greenhouse offers the minimum insulation needed to grow plants year-round – others using less insulation cost too much to heat.

  • Riga Greenhouse offers more window and door ventilation than other units it is class.

  • The RIGA 5 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.

  • Designed, Engineered, and Manufactured in Germany with 30 years of experience

Where is Riga 5 Greenhouse made?

Designed, engineered, and manufactured in Germany by Hoklatherm, a leading manufacturer of commercial and hobby greenhouses, sunrooms, pavilions, pool covers, home additions, and commercial buildings, with 28 years of experience. This Riga Greenhouse has been tested against winds up to 100 miles per hour and has never been blown away (when properly anchored to the ground). No eaves also mean no significant snow build-up! This is not only attractive but aids in shedding snow loads. The Riga Hobby Greenhouse comes standard with 8mm polycarbonate The RIGA 5 Greenhouses is a true representation of a European Greenhouse - designed to be used to grow fresh vegetables, herbs, and flowers in the middle of winter.

Features & Benefits of the Riga 5 Greenhouse

  • Sturdy “onion”-shaped construction that withstands large amounts of snow and strong winds

  • Sidewall material/thickness: 8mm UV-coated twin-wall Polycarbonate

  • Gable material/thickness: 10mm UV-coated twin-wall Polycarbonate

  • Frame material: Smooth finished anodized aluminum frame/profiles

  • First-class insulation:

    • Heavy-duty rubber seals and silicon caulking to seal windows

    • High-quality construction with tightly fitted parts

    • R-value: 3.0

  • Door: 1x wide, heavy-duty Dutch barn style door (30in wide x 79in high), door handle with key lock

  • Roof vents: 4 roof windows (40in wide x 24in length) with an automatic opener (works without electricity)

  • 1x large rear wall window (30in wide x 42in long) which allows for cross ventilation

  • Wind tolerance: 120 mph with 3-second gusts

  • Snow capacity: 30 PSF ground-snow load

  • Included in the Riga 5 Greenhouse Kit:

    • Profiles, glazing, rubber seals, and hardware

    • 4x roof vent with automatic opener

    • 1x barn-style door

    • 1x rear wall window

    • Assembly instructions 

  • Optional accessories:

    • 6” high foundation frame: If you add this, you don’t need a concrete or wooden footer. This foundation frame will attach to the bottom of the greenhouse frame and goes into a trench in order to anchor the whole greenhouse.

    • Premium kit: See details below

    • Door extension kit: Set your greenhouse on a 20-inch stem wall. This kit gives you the missing pieces of Polycarbonate (+ profiles) that go above the doors. It includes 2x extensions for both doors.

  • Rainwater gutter system: No (not possible because of the greenhouse shape)

  • Expandable: No

  • Frame color: Aluminum/Silver

  • Sidewall height (curve): 6ft 1in near shelves

  • Peak height (interior): 7ft 6in

  • Floor space: 165 sq. ft.

  • Dimensions: 9ft 8in wide x 17ft 6in long x 7ft 7in high

  • Assembly time: 2 people – 1 day; 3 people – 6-8 hours

  • Warranty:

    • Twin-wall Polycarbonate: 10 years (prorated after 5 years)

    • Frame: 15 years

  • Made in Germany

  • Shipping Information: Greenhouse ships in 3 boxes, and premium kit ships in 4 boxes. This product is delivered via LTL which is curbside delivery only. The driver will be using a pallet jack and liftgate to slide the crate off and will need help from the customer with the unloading of the framing cartons. We recommend having a couple of people there for the delivery

Made in Germany with 30 years of experience!

The Polycarbonate glazing on the Riga is German made and believed to be of superior quality than the much more common Polygal or GE glazing.

One major advantage of 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. For better anchoring in the floor, you can add the heavy-duty foundation frame.

Riga V Greenhouse Additional Accessories

Upgrade any RIGA Greenhouse with these optional accessories.

Riga 5 Greenhouse Premium Kit

Includes the following Accessories:

  • Riga 5 Greenhouse

  • Riga 5 Greenhouse Foundation frame

  • 10in deep top shelf (attached to greenhouse side)

  • 24in deep regular shelf (hanging from the roof to provide more stability & space)

Riga 5 Greenhouse Door Frame Extension Kit

If you want to raise your door because you set your Riga 5 greenhouse on a stem wall, you can buy a door extension kit. It will raise the height by 20 inches.

Heavy Duty Seed Trays

These polypropylene black seeds trays are made in Germany and are perfect for starting seeds in your Riga 5 greenhouse. They are each 24 inches long x 16 inches wide x 3.5 inches deep.

Illumitex LED Grow Light

The Illumitex Eclipse GEN2 N Bar LED Grow Light Fixture F3 Spectrum comes either with a 9-foot long power cord or without one so that multiple fixtures can be daisy-chained together. Each fixture is 4' long with 12 LEDS and is designed to be installed between 12 inches and 36 inches above the plant canopy. It features 0-10 volt dimming, is damp-rated and dust-resistant, and has a 5-year warranty. The fixture with the plug can be daisy-chained and the fixture without a plug includes a 2-foot-long cord for daisy-chaining. The fixtures have an anodized aluminum frame and are made in Austin, TX.

Misting System

The misting system that comes standard with Royal Victorian greenhouses is available for Riga 5 greenhouse. It offers a convenient way to keep your plants hydrated while lowering the inside temperature of your greenhouse on hot days. The standard system is 14' long and will work for a 20' section of greenhouse, though it can be cut down for use in smaller greenhouses. Made in Belgium, the kit includes 5 misters and ships in 2 pieces with a connector.

Moveable Plastic Hooks

The moveable plastic hooks come in sets of ten. These snap into the grove in the aluminum profiles(frame) and are used to support the growth of tall plants (I.e. Tomatoes or beans etc.)

Powered Ventilation System

A powered ventilation system is available from Exaco to give your Riga 5 greenhouse maximum ventilation on warm days. This system uses a 12-inch exhaust fan, a 16-inch motorized intake shutter, and a single-speed thermostat [model VC115-C], all from J&D Manufacturing. The exhaust fan and motorized intake shutter are installed in opposite ends of the greenhouse to provide airflow from one end to the other.

All of the equipment runs on a 110/115V connection. The powered ventilation system can be purchased with just the exhaust fan and thermostat, where one or more of the roof windows can be used for fresh air intake. If the complete system with all components including the motorized intake shutter is purchased, a plug splitter will need to be purchased separately so that both the exhaust fan and shutter can be used with the same thermostat.

The exhaust fan requires a 12.25-inch x 12.25-inch opening and is usually positioned high on the back wall. It comes pre-wired with a 9 feet long plug-in power cord. The intake shutter requires a 16.25-inch x 16.25-inch opening and is usually positioned in the lowest panel in the front wall. It also comes pre-wired and with a 9 feet plug-in power cord.

Roof Windows

Though this Riga 5 greenhouse already includes a sufficient number of windows, extra roof windows are available to provide even more ventilation. Each window is 40 inches x 24 inches and includes an automatic opener. This opener does not require electricity as it has a special paraffin oil cylinder that expands and contracts based on the temperature. The temperature range on the automatic opener is adjustable.

Roof Window Restraints

The roof window restraint system for each window includes two 15-inch stainless steel cables with nuts and bolts. They are recommended for customers who live in high-wind areas to help prevent sudden gusts of wind from damaging your roof windows.

Roof Window Sash-Locks

This Riga 5 greenhouse already includes enough sash-locks to keep the included roof windows and top halves of the Dutch doors completely shut during inclement weather. Extra sash locks are available if extra units are purchased or if customers want some extra just as backups.

Top and Bottom Shelves

The top and bottom shelves for each side of your Riga 5 greenhouse are available separately from the Complete Accessory Kit. This allows for more floor space and the shelves are strong enough to support the weight of an adult. The top shelf is 13 feet 10 inches long and 10 inches deep and uses polycarbonate inserts to allow for more light. The bottom shelf is 13 feet 10 inches long and 25 inches deep and uses polycarbonate inserts or the optional heavy-duty seed trays can be used.

Adjustable Metal Hooks

Ten of these adjustable hooks are available in one set. These are great for hanging lights, fans, and flower baskets (heavier items) Plastic hangers

Victorian Slat Shelving

The most affordable shelving for Victorian greenhouses is also available for Riga 5 greenhouse. They come in 2-slat or 5-flat sizes and in green or black. The 2-slat shelving is 9" wide x 59" long and the 5-slat shelving is 21" wide x 59" long.

Wheelbarrow Access Plate

A heavy-duty aluminum access plate is available to serve as a ramp for wheelbarrows over the threshold of your greenhouse. The plate is 21" long on each side x 19.5" wide x 1.75" high in the middle where it is hinged.

Technical Documents:

 📝  Assembly and Foundation document

 📝  Assembly Video

📝  Structural Certification: Wind and Snow load 


Do Riga Greenhouses need a heat source for the winter?

The more plants you have, the more heat they will produce. So, it depends on how many plants you are planning to grow. In addition, it depends on what type of plants you want to grow, i.e. kale grows in cool temperatures, whereas tomatoes need more warmth.

Does the Riga come with a base/foundation frame?

No. You can either purchase the foundation frame separately or purchase the premium kit that also includes shelves for just a little higher price.

Is it necessary to buy foundation frame?

It's an optional Base Frame (highly recommended) 6 in. high. Attaches to the bottom of the greenhouse Sits in the ground but can be mounted on top of a wood, concrete, or brick frame/wall. Provides 5 in. of additional inside height M

What foundation/ground/footing do you recommend?

There are plenty of options for you to prepare the ground before setting up the greenhouse. If you choose to purchase the foundation frame, you don't need a foundation. You only need to level the ground and add the material of your choice. We usually recommend gravel, dirt, or pea rock. The foundation frame will go into a trench to provide more stability.

What is the weight capacity for the Riga shelving (9″ and 15″)?

The shelf strength depends on the frame. If the frame that the shelving is permanently attached on to is too weak, the frame will bow outwards. In Riga, 150 lbs is about the maximum weight capacity.

Is a shade cloth required?

This is dependent on what you plan to grow. If you are planning to use the greenhouse to grow and house exotic plants during daytime temperatures in excess of 85-90º F, virtually any greenhouse will need some kind of shade cloth and or misting system in order to keep temperatures down.

How long does the greenhouse take to assemble?

Assembly time depends upon the number of people assisting, how many shelves are added if a foundation frame is added and on personal assembly skills. The assembly time takes from 6 hours to a day (or more) depending on these factors and does not include ground preparation time.

Can the Riga be assembled in the winter, as in can the panels handle being “bent” during assembly when they are cold?

Yes, but everything will be stiff. It is recommended to keep the panels inside (warm) and only bring them out when needed during the assembly process.

How does the automatic window opener work without electricity?

A special cylinder filled with paraffin oil expands and contracts in response to temperature changes. This pushes the window open when it gets hot inside and closes the window when it cools down. The temperature range is adjustable

Can I install an electric fan?

Yes, simply cut the required hole with a utility knife in the polycarbonate glazing either in the back or front walls. No fan is included with Riga greenhouses but it can be added additionally.

What is the wind resistance rating?

Due to its unique roof slope, strong winds are diverted over the roof of the Riga greenhouses. Additional wind resistance is provided through the 4 lateral support bars, which span from the front to the back of the greenhouse.

What foundation/ground/footing do you recommend?

There are plenty of options for you to prepare the ground before setting up the greenhouse. If you choose to purchase the 6” high foundation frame, you don't need a foundation. You only need to level the ground and add the material of your choice. Therefore, we do not recommend a concrete slab. You can, however, build a concrete footing (like a stem wall that is flush with the ground) and fill the inside with gravel, dirt, or pea rock. You can also add the foundation frame as an additional accessory. This will work without a concrete foundation or footer.

Do you recommend a cement foundation?

Cement foundations hold a lot of heat in the summer and a lot of cold in the winter. Therefore, we do not recommend a concrete slab. You can, however, build a concrete footing (like a stem wall that is flush with the ground) and fill the inside with gravel, dirt, or pea rock. You can, however, build a concrete footing (like a stem wall that is flush with the ground) and fill the inside with gravel, dirt, or pea rock. You can also add the foundation frame as an choice. We usually recommend gravel, dirt, or pea rock. The foundation frame will go into a trench to provide more stability

Do the Riga greenhouses require maintenance?

No routine maintenance is required. It is recommended to check annually that all nuts, bolts, and screws are still tight.

How long does it typically take for the shipment to arrive?

It usually takes about 2 weeks(for in-stock items) for your order to arrive. This unit ships from Texas. It takes 1-2 business days to package and then it ships to the shipping facility located nearest to you. The shipper then makes contact to schedule a delivery. Due to the high demand during this pandemic, we are running low on products, and shipping companies take longer than usual. Please, keep this in mind when ordering. We will send you a follow-up email if there is a longer shipping time frame.

 Riga 5 Greenhouse Installation

You will find the assembly of the Hoklartherm Riga 5 Greenhouse to be quick and easy if you carefully follow these Assembly Instructions. The assembly requires only two people, but it will go quicker if you have access to a 3rd person who can help from time to time - this person does not need to be especially strong or handy.

Contents: Hoklartherm inspectors carefully check the contents of each package. Nonetheless, we ask you to do the same: Check the contents of each package against the table of contents in this Manual.

Choose the best location: Please choose, if possible, a sunny and protected location for your greenhouse. Avoid heavily shaded near buildings and/or trees. However, also be careful to avoid bright, direct sunlight (especially in the Southwestern part of the United States). High-intensity sunshine is not good for more than a few hours a day. In such areas, some protection from trees and/ or buildings is recommended. Shade cloth might also be needed (ask your supplier for details). For greenhouses intended for growing vegetables such as tomatoes, cucumbers, and melons we recommend the greenhouse be located in a north-south direction, and for those to be used for flowers and pot plants orient it in an east-west direction.

CAUTION: Do not attempt to assemble the RIGA greenhouse while the wind is blowing - your Glazing Panels might blow away. Do not expose the Glazing Panels, with their special protective film, to bright sunlight or the film will become permanently glued to the Panels before the film is removed during installation.

Getting Started:

1) The Riga Greenhouse assembly has to be executed by at least two people - a 3rd person to help out from time to time is recommended!

2) Work cautiously, with the proper tools. Make sure that the stepladder’s footing is secure!

3) We recommend that you work with gloves (although all of the edges have been filed, it is always possible for you to be cut when handling either the aluminum or polycarbonate parts).

Suggestion: Before you begin - read all these instructions to become familiar with each step of the assembly process. You might decide that you find it easier to complete the assembly process in a different sequence. Several sequences are possible. For example, some people may prefer to build all of the greenhouse frames first and then insert the Glazing Panels, while others may prefer to interchange these steps.

RIGA 5 Greenhouse Maintenance

The Riga greenhouse only requires minimal care and/or maintenance:

  • To clean: We recommend a treatment similar to those for washing your car: Rub with a soft brush and lots of water (very mild soap). Never use abrasive materials as you do not want to scratch the UV filter on top of the Glazing Panels.

  • The pressure cylinder of the Automatic Window Opener should be removed during frost season and be kept frost-free. The rod assembly of the Opener can stay in the greenhouse. Tie the rod assembly arms together with string or wire while the cylinder is not in place to prevent the window from blowing open in stormy weather.

  • Your RIGA greenhouse should be ventilated as much as possible especially when condensation develops. (However, high humidity is preferred by some plants and especially during the seed-to-seedling stage).

Staff Recommendations:

  • Note: Please be sure to check your local building code for any required permits

  • All Hoklartherm Riga 5 Greenhouses are specially ordered and individually inspected and packed with a 1 to 4 week lead time depending on inventory levels and so returns are expensive; please let us know if you have any questions at all

  • Product Assembly usually takes just one weekend with two people (three is preferable) with ordinary household tools as there are no eaves and relatively few connections

  • Maintenance-free design means the Riga only needs occasional washing with a garden hose and recommended annual tightening of all nuts and

About Hoklartherm GmbH

Since 1982, Hoklartherm GmbH has been designing, engineering, manufacturing, and distributing premium greenhouses and outdoor structures throughout the world. The company began as a maker of arched greenhouses and the unique Riga design has remained popular ever since. The company was founded by an engineering graduate named Werner Hollander who had built the first prototype in his family's garden a few years earlier.

From this first arched design has come a series of incremental changes to make the Riga 5 Greenhouse among the very strongest greenhouses available anywhere. The frames have been engineered for strength and to shed off snow and the commercial-grade polycarbonate panels add extra strength to the structure. Hoklartherm now makes beautiful and unique pavilions as well which have been widely installed throughout Europe in parks, commercial settings, outbuildings, and luxury private gardens.

At Hoklartherm's headquarters in Apen, Germany, a section referred to as "Greenhouse World" opened to the public in 2012 to showcase all of their unique designs in one place. At this site is the Hoklartherm state-of-the-art factory that employs all the latest quality control techniques and aluminum processing equipment to ensure the very highest and most precise build quality. Hoklartherm is now Germany's largest manufacturer of premium residential and commercial greenhouses and its structures have been enjoyed by happy customers all over the world.

About Exaco Trading Co.

Exaco Trading Co. began in 1987 as an importer and distributor of a home paint mixing accessory called the Exomixer. Since then the family-owned company has expanded its line considerably to include many different home and garden products, including some of the very best greenhouses from Europe. The company is led by CEO Kimberly Tyson Cook, formerly an award-winning business reporter for the Austin American-Statesman, and Andrew Cook, the VP of Sales and Marketing.

Andrew travels to Europe to check on the manufacturers in person several times a year and has become a leading national authority on all things greenhouse related. He has appeared in many gardening articles and television programs nationally. In fact, Andrew is available for phone support for customers during the installation of any of the premier greenhouses that Exaco distributes from its large A

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