1.  Water:  Best applied at room temperature preferably early in the day.  Thoroughly wet the entire plant, except any flowers.  Follow-up with a second watering approximately 1/2 hour later to help remove any fertilizer salts on your plants.  Frequency for watering is dependent on the variety you are growing, its size, size and type of container and growing medium it is growing in, air temperature, and amount of sunlight.  When actively growing, I water mine more often and less when plant is resting – typically this could be every 1 – 14 days.  For mounted orchids, I water them with a fogger nozzle every 1-3 days.  Do not use water softener or distilled water on your plant and make sure that whatever container you are growing them in has good drainage.
2. Air:  Orchids like fresh moving air.  It not only helps cool your plant, but also reduces potential disease problems.
3. Fertilizer:  Depending on the type you use, (granular, water soluble, etc.), most people apply weekly and less when not actively growing.  I prefer using a balanced water soluble type such as 20-20-20, which I apply after drenching my plants with water followed with a liquid feeding approximately a half hour later.  This allows your plants to absorb more nutrients over a longer period of time and will actually reduce your fertilizer needs.  A light monthly application of Epsom salts, (magnesium sulfate), applied at 1 ounce per gallon of water will also increase the nutrient benefits.  Unless you’ve become experienced growing orchids, I also suggest initially that you dilute your application rate of fertilizer to avoid possible burning, and if your plant isn’t blooming, apply a blooming type product in which the amount of Phosphorus is higher than the Nitrogen number.
4. Temperature:  Most orchids prefer growing between 50 – 80 degrees.  If temperature is less, it may cause a cessation of growth.  If above, it may burn your plant’s leaves.  During the winter months, I suggest you bring any orchids inside when the temperature is expected to be 40 degrees or less.
5. Light Needs:  If you want to have healthy plants that bloom regularly, make sure that in addition to my previous remarks that they receive sufficient light – both intensity and duration.  It is suggested that on a sunny day spread your fingers approximately 1′ above your plant’s leaves.  If they don’t show a shadow on the leaves, it is not receiving enough light, and leaves are usually dark green.  If you see a faint shadow, that is best for most orchids.  If you see a distinct shadow that is good for sun loving Vandas and related species.
6. Containers:  Most orchids are grown in either clay or plastic pots.  The latter holds water longer, whereas clay can get a build up of fertilizer salts that can damage your plants.
7. Growing Medium:  Often when you buy small starter plants including seedlings, they are often planted in sphagnum moss, which will break down within 6 months if kept too wet or receives too much Nitrogen.  Most growers prefer using a fir bark mix containing small pieces of bard, perlite for air space, and charcoal.  Others prefer a volcanic rock medium which provides good drainage and helps to hold your plant in place; but overtime, unless periodically flushed with water, will develop an accumulation of fertilizer salts.
8. Problems:  Orchid plants, like all other living things, can have problems, most of which are due to some change in our normal routine.  They can be:
   • Diseases – (Bacteria/Fungus) – cause plants to rot or shrivel, and eventually die; and is usually due to applying too much water or watering too often.
   • Virus – cause leaves or flowers to be abnormal or discolored, and is caused by using contaminated tools or containers when pruning or dividing plants.  It is best to dispose of infected plant as the problem will only get worse.  By the way, whenever you need to cut off a part of the plant or to divide it, always make certain that your tools are sterilized and that cuts are dusted with cinnamon powder to dry up the wounds.
   • Insects – especially scale, including mealy bugs, thrips, and aphids.  Monitor closely as their presence can mushroom overnight.  Scale is especially severe on Cattlyeas and Cymbidiums, and can often be found hiding beneath the psuedo bulb sheath.  Many orchid growers will have small spray bottles filled with 70% or higher rubbing alchohol to eliminate scale.  For other insects, treat with appropriate insecticide.
   • Thrips – are often found on leaves and flowers causing streaking and discoloration of flowers and leaves.
   • Aphids – are usually feeding on sap from new growth resulting in stunted growth.
   • Spider Mites – feed on all plant parts, and are especially active during hot, dry weather.  Heavy infestations can result in spider-like webbing.
   • Slugs and Snails – Often found in areas that stay damp most of the time, they feed on flower and leaf parts.  While various baits can control this problem, I have found that setting a small throw-away pie pan filled with stale beer near your plants, works just as well.
   • Unfavorable Environment – Extreme temperature fluctuations, exposure to bright sunlight, and/or excessive use of fertilizer, can seriously damage your plants, including leaf burn, premature flower drop, fertilizer salt build-up and break down of growing medium.

Providing good culture, frequent monitoring, and proper application of correct pesticides, (which should be rotated), will usually take care of these problems.  for best control, treat your plants early in the day, and like fertilizer applications, water your plant first and then apply pesticide.

For additional information on Orchid care, visit the American Orchid Society website.