Chapter 3

      Gardeners who I have observed have converted all kinds of spaces to grow rooms: closets, small rooms, pantries, basements, attics, and small sheds. The space must be high enough to allow the plants to grow to 2-3 feet height. A space 4 feet high can be converted into a garden. A space eight feet high can be converted into a two-level garden.
      The area that a space covers is figured by multiplying the length by width. The result is the number of square feet. The size and number of lights used is based on the total area. When the garden is configured, aisle space is left between the plants, so that they can be attended easily. People have an effective reach of 2 to 3 feet, averaging around 2˝. Usually aisles are 1˝-2 feet wide. When the growing unit is placed on moveable platforms, most aisle spaces can be eliminated. Aisles are made by simply moving the units.
      Light fixtures and reflectors should hang from chains mounted directly to a stud, or using a molly bolt, into the lathing. A lamp’s height is adjusted by changing its position on the chain. It is extremely important for the light to be hung securely. Should the reflector fall, it could cause an electrical short in a wet area, which is very dangerous, even life threatening.
      Gardens are equipped with circuit interrupters, which functions as a circuit breaker. This unit shuts off the power in case of a short or an interruption in service.


      The floors of the grow rooms I have seen have been well prepared. Smart growers protect the floors, especially wood or linoleum tile, from water using heavy plastic lining. If the grow room is in a basement or a cool room, where the temperature of the floor is always cool, either the surface has been insulated or the plants had been raised off the floor. This is very important because cold floors draw heat from the containers. Plants germinate and grow considerably slower when their roots are cold.
      There are a number of ways growers insulate the floor. Styrofoam insulation, which comes in sheets or rolls, has been placed over the floors. This material has the added advantage that it is very reflective, so that any light hitting this surface bounces back to the plants. Plywood is often placed over a layer of insulating material. Plants are raised off a floor using a table or wooden boards. Shipping pallets provide air spaces so the warm air circulating in the room can reach the containers.

Heating the Roots

      Cold roots slow growth to a crawl. Heating cables or a heating mat made for heating soil or containers keep the roots warm. Some cables and mats have a built-in thermostat to keep the temperature a constant 70-75 degrees. Heating cables and mats are available from many garden shops. They are convenient to use and consume only a few watts.
      Growers use room temperature or lukewarm water to irrigate the plants so that the roots are not shocked and cooled down. They use lukewarm tap water, or heat the water in the reservoir. Small reservoirs (up to 100 gallons) are warmed using an aquarium heater and thermostat. Larger tanks are heated using a water heater. An ideal water temperature is 70 degrees.

      Here are some floor plans from typical gardens.

  1. A closet 9 feet high by 36 inches deep by 40 inches wide. This space did not have convenient dimensions for using fluorescents, so it was easiest to use a MH or HPS lamp (see page 28). The total space was about 10 square feet. A 250 watt MH lamp lit the space. A shelf was constructed at half the height. The shelf supported a second garden. Each garden was powered by a 250 watt MH lamp. Ventilation is provided by keeping the door open. No CO2.

  1. A closet 8 feet high x 2 feet x 9 feet. As a single level unit the closet was originally illuminated by 4 8 ft fluorescents. This was converted to a 400 watt MH mounted on a Solar Shuttle type track. The garden was modified to 2 shelf gardens. The top one still under the Solar Shuttle and MH. The bottom one uses two 250 watt HPS lamps permanently mounted. A small oscillating fan mounted on the top of each garden keeps the air flowing. Most of the time the doors are kept open. When they are closed, wide cracks between the doors help bring in fresh air. No CO2.

  1. A room 9 feet high x 12 feet x 10 feet, all growing on one level. It is lit using a MH and a HPS, each 1000 watts. The lights rotate on a Whirlagig so that light is spread more evenly. Ventilation through a window fan regulated by a thermostat. CO2 using a tank and regulator. Steel shelving with three levels, each 4’ x 2’ with 4 fluorescent tubes is light sealed from the rest of the room using opaque curtains. Clones are generated in this space.
          The room had 3 aisles. The first started along the door on the side of the room and extended most of the 12 foot length of the room. It was 24 inches wide. Two additional aisles branched off from the main aisle. They paralleled the width of the room and started at 2˝ feet from the side wall. Each was 18" wide. They each extended a length of 7 feet from the wall leaving a 2 foot growing space at the end of the garden. The total growing area of the garden was about 100 square feet including growing shelves.
          This room could have been configured as a shelf growing space using the same aisle space. Lighting would be provided by 400 watt HPS units mounted on the ceiling of each shelf. A total of 6 units would be used. Total growing area would be about 190 sq. ft.
          Ventilation from this space was via a fireplace. A one foot diameter tube sucked air from the top of the room and using a powerful fan mounted inside the tube, drove the air out.

  1. A basement space 5 x 5 feet 40 inches high. To conserve vertical space fluorescents were used. Ten were mounted permanently to the rafters overhanging the garden. Two 4 foot fluorescent tubes were mounted on each of three sides of the garden to encourage healthier growth. Reflective surface and heat preservation were accomplished by hanging mylar by the rafters along the perimeter of the garden. The floor is always cold so a thin piece of plywood was placed over a vinyl plastic sheet covering R11 insulation. A tank with regulator distributes CO2. During winter, rather than trying to heat the air in the space, heating cables keep the roots and other plant surfaces warm.

  1. An attic garden Raw attic space has been cordoned off by hanging reflective curtains of astrolon in an area 6 x 6 feet. A 400 watt HPS light is hung from the rafters over the garden. Draft provides ventilation. Growers have reported that attic gardens have a lot of problems because they are subject to severe weather shifts and extreme seasonal conditions. If an area can be contained, either by building walls or using heavy curtains, it is easier to maintain reasonable growing temperatures. In winter, temperatures can be raised using a gas heater regulated for indoor use. The heater emits CO2 as well as heat. During the summer attics must sometimes be abandoned because the temperature gets too high.


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