Plant your Maxillaria tenuifolia in a planting container that is just slightly larger than the one your orchid came in. Use a commercial orchid potting mix or make your own well-draining growing medium by combining equal parts redwood bark, peat moss, charcoal, chopped tree fern fiber and volcanic stone. Place the potted orchid within 8 feet of a bright window where it can receive at least four hours of filtered sunlight each day.
Maintain an indoor temperature and humidity level that mimics South America's tropical climate. Set your thermostat to maintain an indoor temperature between 68 and 75 degrees Fahrenheit. Make sure to keep the temperature above 55 degrees F. to avoid forcing the orchid into dormancy. Use a spray bottle to mist Maxillaria tenuifolia orchids with room temperature water daily to increase the humidity to your houseplant.
Water your Maxillaria tenuifolia orchid slowly and thoroughly, then allow the potting mix or growing medium to dry partially before watering again. Water the orchid weekly, using the ice cube watering method for best results. Place three to four ice cubes on the surface of the potting mix or growing medium; arrange the ice cubes to prevent them from touching the foliage directly.
Fertilize Maxillaria tenuifolia orchids monthly using a diluted solution of 20-10-10 fertilizer. Mix the solution to just one quarter of the recommended strength to ensure that your orchid doesn't receive too many nutrients at once. Follow the application instructions on the fertilizer packaging for best results.
Re-pot your Maxillaria tenuifolia orchid every two to three years, or whenever its roots start to outgrow the current planting container. Take the orchid from its container and discard the used potting mix. Examine the root system and cut out any roots that are brown or mushy. Re-pot the orchid in a larger planting container, if necessary, using fresh orchid potting mix or homemade growing medium.