UMass Extension Greenhouse Crops and Floriculture Program

Garden Center Design Guidelines

Site Considerations

Garden centers, retail greenhouses and farm stands are a popular way of marketing plants. Most operate year-round but some are open only on a seasonal basis, limiting sales to the spring bedding plant season and major holidays. In recent years, most of the major chain stores have installed garden centers to market to their large customer base.

If you are considering starting a garden center operation, it is best to start by defining the products that will be sold, who the prospective customers are and where they live. It is also important to spell out your own expertise and interests.

What will you sell?

A good first step is to determine what you will sell. Is it only plants or will you carry other items? Will it be year-round or will it be seasonal? These factors help to determine the type of facilities that you need.

The garden center facilities may contain a permanent wood or steel frame building with retail sales space, office, work area, cooler, storage and restrooms. The area for each should be defined and then totaled to get the size of the building. As most garden centers include a greenhouse, the size and attachment of this is important for traffic flow and checkout. Also included may be a lathhouse for sun and wind protection of plants, a nursery, display gardens, picnic area and outside storage of bulky materials such as mulches.

Many growers sell other items that are allied with plants. Hardgoods, seeds, fertilizers, mulches and produce entice a potential customer to stop. Pumpkins in October and Christmas trees in December expand the season. Crafts and gift items expand the sales. I know of several operations that added an extensive Christmas shop which provides about half of their yearly income. What you sell depends on your customer base, nearby competition and what your feel comfortable with.

Location, location, location

Finding the perfect spot for a garden center may be difficult. It should be near a population center or on a road that has a high traffic count. If not you may have to do considerable advertising to draw customers to your place. Developing a good reputation for quality, variety or specialty products can also help.

A good site has a minimum of 5 acres. This allows for structures, parking and gardens. If production will also be included in greenhouses or outdoor beds, 10 acres or more should be considered.

The site should allow for removal of storm and surface water. A slope of about 2% is ideal as this allows natural drainage without erosion. Sites with steeper slopes will be more expensive to develop. Swales or curtain drains around buildings may be needed to keep the area dry. The floor of buildings should be 6 to 8 inches above surrounding ground level. Runoff from the parking and driveway areas should be diverted away from the buildings but not create problems for adjacent properties.

Good location and visibility attract customers. At 50 miles per hour the driver has less than 3 seconds to view your business. The appearance including the buildings, landscaping and plants that are displayed should make a favorable impression.

Access for vehicles is also important. The greater the site line the safer the egress. If possible there should also be a slow down lane to let other vehicles pass. A permit for highway access is usually required.

Some growers have found that setting up a temporary greenhouse in the parking lot of a shopping center or mall can give good exposure and expanded sales. The greenhouse needs to be anchored to resist the strong winds that frequently occur there. If it will be there year-round, it needs to meet snow load requirements.

Complying with zoning and building code ordinances

Zoning governs land use. Check with the local officials to see if retail facilities are allowed. In some communities, retail sales are allowed on farm property if all or part of the products sold are grown on the farm otherwise you will have to build in a commercial zone. Zoning regulations cover frontage and setbacks from property lines, parking area size, signs and buffers from neighboring property.

A surveyor map showing the location of the property boundaries, greenhouses, parking and other facilities may be required. Be sure to include areas for future expansion to reduce the hassle of getting approval later on. This way the commissioners see the total picture of what they are approving.

Entrances and other facilities will have to comply with the Americans for Disabilities Act. Many codes leave interpretation up to the local inspector and this has caused problems for the grower. Many building inspectors are not familiar with greenhouse construction and may have to get help from the state building official.

Parking should be convenient to attract customers. It should also provide adequate space for customers to load plants and other items into the back seat or trunk. Zoning regulations frequently specify the number of parking spaces needed based on the square footage of retail space. Perpendicular parking generally requires a 10' x 18' space/car and a 24' driving lane. In angle parking the width of the space remains the same but the length of the space and the driving lane width decrease. Some zoning regulations require paved parking areas. Because garden centers have maximum sales on only a few weekends during the spring or on holidays, you may be able to convince the zoning board to allow some of the parking area to be non-paved as an overflow area.

Setbacks from front, side and rear property lines may be required. These can be as much as 100' wide. Fencing to screen adjoining neighborhood property may be desirable to keep down noise, dust and odors.

Good outdoor lighting improves visibility, safety and the sense of security. Active yard areas and driveways require only 2-3 foot-candles (ft-c). Select full-cut-off shielded fixtures that keep light from going uselessly upwards or sideways. Good lighting can be achieved with the fixtures mounted less than 20 feet from the ground. Select energy efficient high-pressure sodium or compact fluorescent bulbs. Security night lighting should only be activated when an intruder enters the area.

Construction plans

Once the site plans have been approved, you will need construction plans for the buildings. You may want to hire an architect to develop the plans. A well-designed, aesthetically pleasing garden center blends into the surroundings.

Architects generally deal with the appearance and aesthetics of a building. Some architects can also provide engineering expertise. An engineer handles the structural and code aspects of a job and deals with the building inspector. Sealed plans from a professional engineer (PE) may be required. The architect or engineer can also help you select a contractor and will oversee the construction phase.

The most desirable style structure is a clear span, wood or metal frame building. This allows flexibility in interior layout. Wood post and beam structures provide a country appearance and can be made very attractive. Vertical groove or board and batten siding is easy to install. A painted metal roof gives a long, maintenance free, service life. A modular metal building is an alternate that is available in many sizes and styles.

Building walls and ceiling should be insulated to conserve heat and reduce noise. Fiberglass insulation is acceptable in buildings that will not have large quantities of plants. Foam insulation is better where excessive moisture will be present. A good vapor barrier on the warm winter side will prevent moisture from getting into the insulation. A small exhaust ventilation system should also be installed to remove excess moisture and odors.

For winter operation a heating system is needed. The least expensive are gas-fired unit heaters that circulate air throughout the building. These are available in sizes to fit individual room areas. They should be vented to remove flue gases and moisture. Some garden centers have installed a wood stove for supplemental heat and atmosphere. These need to be installed safely with adequate distance to combustibles. They should also be guarded to keep children away from the hot surfaces.

Building codes are much more restrictive for a retail buildings which comes under the mercantile section of the code. The code may require things such as sprinklers, lighted fire exits, enclosed heating system and handicapped accessible restrooms. Polycarbonate glazing on the greenhouse may be required rather than film plastic to meet the fire code rating.

Garden center floors should be concrete for durability and ease of cleaning. Use a wood-floated or brushed surface or coat with a layer of epoxy paint with an anti-skid additive. Slope floors to drains. Garden center floors tend to become slippery from irrigation water.

Do you have access to utilities?

A minimum of 10 gallons per minute water supply is desirable unless a storage tank is used. This is needed to supply one hose for watering the plants. The water supply should be tested to assure that it is safe for drinking and does not contain any chemicals that will affect the plants.

An adequate electrical supply is needed to handle heating, ventilation and lighting equipment in the garden center and other buildings. A minimum of 100 amps should be installed.

Telephone service is important for receiving calls and connecting to the internet. If you live any distance from the garden center it can also provide a temperature and security alarm.

If the garden center is not located where a sewer system is available, a septic system will have to be installed. This requires percolation (perk) tests to determine soil suitability and the size of the leach field. Septic system installation has to be done by a certified installer.

Landscaping draws attention to your business

It's surprising how many garden centers have poor landscaping. Attractive gardens and plantings can draw attention to your business every time someone drives by. It gives the customer ideas on how to use the plants that you have for sale. It also helps to beautify the community.

You can also draw attention to you business by installing large glass windows on the front wall of the garden center building or greenhouses. Use this area to display colorful plants.

Interior Layout

Flexibility is the key to good sales area layout. Product displays should be changed on a regular basis to provide a fresh look to the products. This helps to draw customers back to your establishment.

Items can be placed on benches, racks, hooks from the ceiling or on the floor. A variety of sizes and shapes help to display products to an advantage. Plants should be displayed in large groupings to draw attention to that area.

Conventional arrangement of product usually places demand items at the rear of the sales area to draw the consumer through other impulse items for sale. Other arrangements are also acceptable and experience is usually the best teacher.

Garden Center Greenhouse Design and Layout

Most garden centers have one or more greenhouses to draw attention to their business. A garden center greenhouse differs from a production greenhouse in the way it is set up and operated. In some cases, the greenhouse may be used exclusively for retail sales. Other growers use greenhouse space for production during slack sales times. Some growers allow the public into the production greenhouses but this may present safety and plant disease related problems.

Select a greenhouse style to fit your needs

Retail sales greenhouses should be convenient to the garden center building. They can be separate but a covered connector between allows access in all weather conditions. Controlled access also allows for customer traffic flow and reduces the number of control points and cash registers required.

Hoophouses

Most temporary greenhouses are hoophouses with roll up sides for ventilation. Shade cloth may be needed over the roof to reduce the heat load during the summer. Heat is not necessary if the greenhouse is operated for sales only in the late spring. A portable, vented heater could be installed for cold nights.

Some manufacturers make a portable structure that is easily assembled. It can be held to the ground with screw anchors, concrete blocks or bags of sand. Anchorage will probably be of major concern to the building official so that the greenhouse doesn't move in a heavy wind.

Small garden centers and farm stands use standard hoophouses to market plants. These may be operated seasonally or year-round. Frequently they are used for both production and sales. Several greenhouses may be located together to get the desired space. Provide at least 10' between greenhouses for snow collection.

It is better to provide separate greenhouses for production and sales as it is difficult during the busy spring season to keep all areas clean and neat. There may also be conflict during the day between customers and employees that are watering and tending plants. It does require more labor for moving plants from production areas to the sales area and this needs to be considered.

Greenhouses for retail sales should be 25' to 30' wide to provide flexibility in bench layout and aisles. The length should be limited to 96' otherwise the plants have to be carried too far.

Hot air furnaces provide the most convenient heat as it is easy to shut a greenhouse down during the winter without draining a boiler system. Distribution of the heat is with HAF fans or poly ducts. Ventilation for early season production is best done with fans. When the weather warms up, roll up sides work well.

Gutter-connected greenhouses

For larger operations, multiple bays of a ridge and furrow design is a good choice. This provides space for bigger displays of plants under one roof. Try to achieve the effect that the department stores create with different sections devoted to different types of plants. It is more difficult, however, to separate production from retail sales if the ridge and furrow house is used for both. Gutter height should be 10' or 12' to give space for hanging baskets.

Gutter-connected greenhouses for retail sales are usually open year-round. In northern climates, concern for snow loads must be addressed. Although a hot air heating system can work well, a hot water system with fin radiation around the perimeter and under the gutters will give a neater appearance with less obstructions. It also melts any snow accumulation quicker.

Fan ventilation will give the best environment control during warm weather but tends to be noisy and annoying. If fans are used, be sure they are the slow speed, belt driven type.

The new open roof greenhouses or those with large vents will work well for sales if they are controlled so that they close when it starts raining. Research has shown that temperature control can be good if a site is selected that intercepts the summer breezes.

More permanent glazing means less maintenance

Polycarbonate structured sheet glazing is desirable for the roof and sidewalls of permanent greenhouses as there is little maintenance. It may also be required by the building code. Polycarbonate will give satisfactory service for up to 20 years. If the greenhouse is covered with poly, use an air-inflated double layer to reduce the flapping caused by the wind. The sidewall or endwall facing the road should have large tempered glass windows to display flowering plants and attract customers.

Keep benching flexible

Benching systems should be portable and flexible so that the visual impact and display can change from season to season. Pressure treated wood or galvanized expanded metal provides good support for the plants. A modular system of benchtops supported by concrete blocks or a pipe frame allows the arrangement to be changed.

Layout of benching should provide for wide aisles. A peninsula system usually gives more display space than long benches. Step benches can be used to increase space and bring the plants closer to eye level.

Hanging basket can be placed on racks or hung from overhead trusses. Locate the plants where they will not drip on customers.

Be sure to arrange the space to allow for free flow of customers. In larger greenhouses provide shopping carts or wagons for customer convenience. Leave adequate space for a checkout counter near the exit.

Provide a good floor surface for customers

For most retail greenhouses a paved floor over the whole area is desirable. This provides convenience for customers and allows flexibility in arranging benches and displays. Either concrete or asphalt can be used. If asphalt is used, paint it a light color to reflect heat. Drains should be provided to collect water from the plants and to keep the floor dry. Wet floors can be slippery.

Integrate the greenhouses into the total facility

Frequently the greenhouse facility is attached or adjacent to other buildings that may be used for sales. Entrances, traffic patterns and checkout counters need to be considered. Try to separate the traffic entrance for customers from the truck delivery entrance. This increases safety and keeps the noise away from the sales area. If outdoor sales areas are included, fencing is needed for security.

In the plan, provisions should be made for expansion of both the greenhouses and the permanent buildings. Try to create a unique appearance that blends the buildings with the natural surroundings. This makes the operation easy to identify for your customers and potential customers.

Publications

These publications provide additional information and resources. They are available from the Dept. of Natural Resources Mgt. & Engr., 1376 Storrs Road - UConn, Storrs CT 06269-4087. Make check payable to UConn. Prices include postage and handling.

  • Establishing and Operating a Garden Center - NRAES-161, 66 pages, $19.00
  • Facilities for Roadside Markets - NRAES-52, 32 pages, $11.00
  • Produce Handling for Direct Marketing - NRAES-51, 26 pages, $11.00.
  • Greenhouse Engineering - NRAES-33, 212 pages, $30.00.
  • Energy Conservation for Commercial Greenhouses - NRAES-3, 100 pages, $20.00.
  • Greenhouses for Homeowners and Gardeners - NRAES-137, 200 pages, $30.00.
  • Herbaceous Perennial Production: A Guide from Propagation to Marketing - NRAES-93, 220 pgs, $30.00
  • Workforce Management for Farms and Horticultural Businesses - NRAES-56, 110 pages, $20.00.
John W. Bartok, Jr.
Agricultural Engineer
Natural Resources Mgt. & Engr. Dept.
University of Connecticut , Storrs , CT

May 2005