Growing Orchid's Indoors

By: Judy Cole 

All of us at one time or another have grown orchids inside our homes. Usually until our collections get so big that we have to move them out before they move us out.

There are advantages and disadvantages to growing orchids indoors. I find the best advantage is that I see my orchids every day. I tend to notice their general condition, whether they’re getting too dry or staying wet too long, and any bug or disease problems that are starting to crop up can be taken care of before it becomes too much of a problem. The disadvantages include trying to maintain a proper environment indoors. Very few of us want to live with 80% humidity inside our homes. Also watering can be a challenge once your collection grows or if you add mounted orchids.

I’d like to attempt to go into the basics of in-home growing in this article, and then try to give you a few quick and fairly cheap fixes to allow you to better grow orchids inside.

Lets examine the factors that allow us to grow orchids or any plants indoors: light, water, temperature, humidity and air circulation  

LIGHT:

The first thing to take into consideration when deciding which orchid to buy is the kind of conditions you have in your growing area. Different orchids require different light levels:

low to medium (500 to 2000 foot candles)

Phalenopsis, Ludisia, Paphiopedilum

medium to high (2000 to 4000 foot candles)

Cattleya, Oncidium, Dendrobium, Vanda

Without enough light your plant will be dark green, the pseudobulbs may be soft and if it does flower the blooms may be undersized. Probably 90% of the time, if you’re having problems with blooming your orchids the problem is not enough light. It’s easy to remedy this problem, if you have a brighter window you can move it slowly to the brighter area so it doesn’t sunburn. You may also want to add some supplemental lighting. Our Home Depot stores sell a 4-foot florescent light with a frame, or if you wanted something cheaper you can make your own frame out of PVC and hang a shop light from it. If you don’t have 4 ft of space you can use the clamp lights with metal shades (roughly $5 at Home Depot) and hang 2-4 of them in your area.

I’m sure many of you have seen the light carts listed in greenhouse supply catalogs, most of these go from $400 to $1000. It’s also easy to make these with 4ft by 6ft high metal ventilated shelving units and 6 4 ft shop lights from Home Depot. See this site for instructions on how to build one.

www.collins-consulting.org/orchids/orchidshtml

The type of light bulbs you use can vary also. Incandescent, fluorescent, HID, and a wealth of other lights are now available. I have found full spectrum fluorescents are fairly cheap and work well for me without the heat of incandescent lights. 

WATER:

Watering is the second area we’ll discuss. Next to lighting, this can be the hardest area for beginners to master. More orchids are killed by overwatering than underwatering. If you are prone to over water I would consider re-potting your orchids into clay pots, clay will breathe and water will dissipate more easily, plastic pots are great for people who tend to underwater, since plastic does not breathe and holds water longer. I usually only water once a week; in winter when it’s cloudy I water maybe once every 10 days. Mounted orchids take more care; I wet down my mounts in the bathtub 2-3 times a week in the summer and only once a week in the winter.

For fertilizing I use the weekly/weakly plan with one week a month of no fertilizer to flush out excess salts. 

TEMPERATURE: 

Orchids generally fall into 3 groups when classified by temperature.

Cool or cold growing (50-55F at night, 60-70F day) These are very hard to grow here in Austin (unless you keep your air conditioner in the 60’s through the summer) Even the ”warmth tolerant” ones I’ve tried buckle in mid July. Examples: Draculas, Masdavaillias, Ophrys, ect.

Intermediate growers (55-65F at night, 70-80F day) These can go either way, some can be grown here. I have had some luck with Cymbidiums outside as well as Zygopetalums inside.

Warm growers (65-70F at night, 80-90F day) This is our group! Many of these do very well here. Some can take temps into the 100s for short periods of time. Examples: Phals, Oncidiums, some Dendrobiums, Vandas.

In the home it’s much easier to control temperature than outside, thanks to central air. You may use fans or ceiling fans to cool and circulate air.

Most orchids need a drop in temperature at night of 10- 15 degrees to induce flowering, this can be difficult indoors, I tend to let my sunroom get into the 85 degree range during the day, then it’s generally not too hard to get it down to 75 at night (except in the middle of August).  

HUMIDITY AND AIR CIRCULATION:

For most orchids indoors, a humidity level of 40-70% is optimum. Luckily here in Austin, our humidity stays around 50% for a major portion of the year. So we don’t need quite as much help as some of the drier areas of the country. You can increase humidity around your plants by grouping them together, using plastic plant saucers filled with pebbles in water (don’t let the water touch the bottom of the pot though), or humidity trays.

You may also want to use humidifiers to help raise the humidity in the room. There are many types of humidifiers, generally they are classified as warm mist, cool mist and ultrasonic. I have tried all three and I seem to find ultrasonic works best for me, they are virtually silent and put a small white fog of mist out into the air.

The one disadvantage of ultrasonic is that the mist can leave a white residue on some of the plants closest to the humidifier so from time to time I clean off the leaves with lemon juice or milk and water. It’s easy to find all 3 types of humidifiers at Wal-Mart; the simplest Vick’s baby humidifier only costs $10. They also have ultrasonic models from $20 to $40. It’s also advisable to buy a hygrometer (humidity meter) these can also be found fairly cheaply at Wal-Mart.

Air circulation helps orchids in many ways; it cools the leaves and reduces the chance of bacteria and fungi forming on the leaves of wet plants. Generally air circulation isn’t as big a problem indoors as out. Many of us use ceiling fans daily during the summer. I also have 2 oscillating fans on opposite sides of the sunroom that usually run 24/7 to keep air moving. In the fall and early spring I also open the windows to get fresh air in the house. 

I hope this helps a little in your attempts to grow orchids indoors. If you have any questions, feel free to e-mail me at jcole@austin.rr.com or approach me at a meeting, I made a New Years resolution to attend all the meetings this year and with the exception of one, I have. I’d be happy to help you with any problems or questions you might have.