Light.

We grow our collection of orchids indoors from October 1st to April 30th (210 days). During summer, the collection is moved outdoors to a shadehouse. Our indoor growing area has two large windows. One window faces southeast and the other window faces northwest. During winter the southeast window provides direct sunlight for three hours early each morning, 7:30AM to 10:30AM. The northwest window provides only one hour of direct sunlight in the late afternoon, 3:30PM to 4:30PM. The windows are on opposite ends of a very large room and therefore no one plant receives sunlight from both directions. In fact, only the plants that are within three feet from a window receive benefit from the sun. This small duration of sunlight is only adequate to keep the plants barely alive until spring.

In order to grow healthly blooming orchids, we must supplement the natural sunlight with artificial light. We use three 400 watt overhead Metal Halide (MH), High Intensity Discharge (HID), light systems. Two of our overhead MH-HID light systems are Hydrofarm Super Grow Wing Systems. The third MH-HID is a Hydrofarm Radiant System. All three systems consists of a 15 pound lamp fixture attached to a 30 pound ballast with an 8 foot long power cord. The lamp fixture are suspended from the ceiling by two metal chains attached to hooks screwed into the ceiling rafters.

At the beginning of the indoor growing season, the bottom of the lamp fixture is raised to about 34 inches above the tabletop. Every two months, we lower the MH-HID fixture by two inches. At the end of six months, the fixture has been lowered to 28 inches above the table top surface. Metal Halide lamps quickly reduce light emissions. To produce a consistent output of light throughout the growing period, the light height should be routinely adjusted.

Specific HID lamp details are listed on an additional page.

Temperature.

In winter, our collection of orchids must tolerate cool conditions. It's common for the overnight temperature in the plant room dip to 55F-58F degrees. Daytime temperatures reach 70F-74F degrees. We have observed that the plants perform better with diurnal temperature changes of 15 degrees or greater. Daily temperature changes appear to induce flower formation.

Humidity.

When we first started growing orchids, we misted the plants each morning with a handheld water sprayer. We found this to be a waste of time as it only briefly increased the relative humidity in the room. Low humidity would return to the room shortly after misting.

The misting practice produced wet leaves that resulted in fungal and bacteria disease outbreaks. Disease killed more plants than the lack of proper humidity. We no longer mist our plants and they now grow with many fewer health problems.

We found that a large plastic dog kennel tray (48 inches by 30 inches with a 1 inch rim) solved our humidity issue. We placed the dog kennel tray on top of two metal rack shelving units to form a table top. The shelving units could have their legs cut to size for a table height of your choice. The tray was covered with upright clay plant pots each containing a plastic pot as a liner. The tray was finally filled with 1 gallon of medium temperature tap water. This produced a water level in the tray of about 1/4 inch.

Orchid media should never be allowed to sit in water. It decomposes quickly and the plant roots will rot. As long as we never overfill our tray, our orchid media never sits in water. True - the water is absorbed by the clay plant pots, but the orchid media within the plastic liner is never in contact with wet clay. The orchid plant is surrounded by wet clay pots and when the water begins to evaporate from the pots, the relative humidity around the orchid increases. We find that the relative humidity in the plant area stays consistently between 55 to 65 percent during the winter, and often moves above 75 percent in spring.

Watering.

When we first started growing orchids, we watered our orchids once per week. On the same day every week, we move all of our orchids from the growing area to the kitchen countertop. We then moved a few orchids into the kitchen sink. We watered each plant by showering them under a spray of water from the dish rinse sprayer nozzle. After a 20 second spray, the plant was set aside and the excess water was allowed to drain off. After the water had drained away, the plant was returned to its growing table. This proved to be a long and tedious procedure that was eventually abandoned for an improved method.

Our next watering method involved breaking the collection into three sections. Each section was given a plant tag. The plant tag was labeled with the name of a weekday (Monday, Tuesday, Wednesday, etc). The label indicated the day of the week that the plants in that section should get watered. We would only water one third of the collection on any one day. This was a great improvement over watering every plant during one giant insane watering marathon.

We also abandoned our procedure of using well water sprayed on plants sitting in the kitchen sink. We moved using Reverse Osmosis (RO) water. We filled a bucket with RO water and hand dipped each plant. The hand dipping process greatly reduced the amount of time spent on watering. We went from eight hours once per week, to one hour three times per week. Our collection size was about 300 plants.

Fertilizer.

We fertilized weakly weekly with 1/4 strength fertilizer. Originally we started using 19-31-17 blossum booster fertilizer. After 18 months, there was no noticeable difference to the number or frequency of flowers using blossum booster.

We switched fertilizers. We started using 20-20-20 fertilizer and had satisfactory results. We installed a RO water system and read some warnings about micronutrient difficiencies. We switched fertilizers again. We started using 13-3-15-Ca8-Mg2 Hilltop Orchid fertilizer. We again had satisfactory results.

We were never certain that the brand or composition of the fertilizer made any difference with flowering. But it never did any harm. If you decide to fertilize, always use a low dosage to avoid burn roots and leaf tips.

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