1. Growing orchids in the home
Orchids have a bad rap; but are in reality some of the toughest plants out there…

2. Growing orchids in the home
… but they are very different from other houseplants
Understanding how orchids are different from other plants is the key to growing them well!

3. Growing orchids in the home
Different orchids have different needs
Pairing an orchid with the correct potting medium, light level, temperature, and watering schedule is critical to success
This is not as difficult as it may seem, and the orchid itself will often give you clues about what it needs

4. Growing orchids in the home
The main factors involved in growing orchids are:
Water: Both quality and frequency
Light
Temperature
Humidity
Air movement
Potting media
None of these are separable from each other; a change in one will impact all the others.

5. Selecting an orchid
Visually check the plant for signs of disease, pests
The plant should not wobble in its pot; this can be a sign of root loss
Ideally, the plant should have new growth emerging and green (or red) root tips

6. Pots
An orchid pot should have enough holes that water can drain freely, quickly, and completely from the pot
Plastic pots are better for plants that need more moisture, or growers that prefer to water less often
Clay pots are better for plants whose roots need more air, but they dry out faster
I personally use both, depending on what I am growing

7. Media
There are many different types of media; the most commonly used are bark and sphagnum moss
Bark holds little water, and lasts for a relatively long time (> 2 years)
Sphagnum holds a lot of water and air at the same time, and needs to be replaced more frequently (about 1 year)

8. Sphagnum moss
Sphagnum moss holds water, nutrients, and air extremely well
However, it can be tricky to water properly, and once it starts to sour goes bad very quickly

9. Bark Most orchid growers use graded fir or pine bark
Bark is a more forgiving medium if you are heavy-handed with the watering can
Bark also lasts a comparatively long time; the best I have ever used is Orchiata, which lasts 2-3 times as long as other brands

10. Other Media
Other popular types of media include coconut coir or husk chips, lava rock, tree fern or osmunda (not used much anymore), perlite/peat mixtures, as well as rockwool, LECA, and other inert hydroponic media
Take-home: Most of these can be used for most orchids as long as the watering schedule complements the medium and the orchid

11. Air Movement
Gentle air movement is an important and often-overlooked aspect of good orchid culture
Orchids come from open, breezy environments; a gentle breeze provides vital gas exchange and can prevent some diseases
A ceiling or oscillating fan set to low will be of great benefit to your orchids

12. Air Movement
Though air movement is beneficial, too much (especially with low humidity) can cause the plants to dry out too quickly, and may damage moisture-loving orchids
Take-home: Adequate air movement will help ensure robust growth, and help to ward off disease caused by stagnant conditions

13. At the root of the matter…
Most cultivated orchids’ roots evolved hanging in the air, and they are dependent on gas exchange
Over-watering, failure to repot in a timely fashion, and planting the plants in improper media can all result in dead roots because of inadequate access to air

14. At the root of the matter…
Healthy roots are vital to healthy orchids!
Epiphytic orchid roots are covered with velamen; the thicker they are the more air they need
For practical purposes, this means they need to have a coarser medium and dry out faster in between waterings (coarse bark, coconut husk chips, rock)

15. At the root of the matter…
Healthy roots are vital to healthy orchids!
Epiphytic orchid roots are covered with velamen; thinner roots often (but not always) need more moisture
Thinner-rooted orchids (Oncidium, Dendrobium) need a finer medium that will hold more water (medium or fine bark, sphagnum, turface)

16. At the root of the matter…
Healthy roots are vital to healthy orchids!
Terrestrial and semiterrestrial orchids (Cymbidium, Paphiopedilum, Phragmipedium) typically have hairy, thick roots adapted to consistent moisture
These types will do best in a medium that holds more water (peat-based mixes, fine bark, sphagnum)

17. At the root of the matter…
Take-home: Air movement and proper watering/media selection are critical to good orchid culture; healthy roots make healthy plants

18. (demo) old/new media, repotting

19. Watering Watering should be done in the morning
Don’t get water in the tops of the growths
Ice cubes?
Why it works, why it doesn’t…

20. Watering Water until lots of water runs out of the pot
Thoroughly saturate media at every watering
During winter, use tepid water to avoid cold damage
Take-home: Proper watering is the key to success with orchids

21. Water quality
Epiphytic orchids evolved on a “diet” low in mineral nutrients
They are intolerant of large amounts of dissolved solids in their water

22. Water Quality
Our municipal water in Colorado is mostly within the limits for successful orchid cultivation
Sodium-softened water is poisonous to orchids
Reverse Osmosis

23. Water quality
Well water can make orchid cultivation difficult, but some growers simply flush their plants with lots of water periodically to get rid of salts
If your water is bad, you can also buy distilled water in jugs and mix it 50/50 with your water
Take-home: Relatively pure water is a great asset when growing orchids, but regular flushing can help mitigate bad water

24. Light Most common orchids need bright indirect light
Orchids can be grown on windowsills: East, South, West, and North exposures
Some growers grow under lights or in a greenhouse

25. Grow lights
A certain Coloradan industry has made state-of-the-art indoor gardening devices plentiful, and in some cases cheap
I grow exclusively under T5 fluorescent lights: cheap, energy efficient, and cool-running
Some diehards use HIDS…

26. Light levels: Leaf nothing to chance!
Leaves give cultural clues:
Dark green leaves usually indicate insufficient light
Yellow-green leaves or leaves that turn red-purple indicate too much light
Shoot for medium-to-light grass green

27. Leaf nothing to chance! Leaf shape can also give cultural clues:
Leaves that are hard and thick indicate that the plant comes from a semi-arid locale, or somewhere with a seasonal dry period
Thick pseudobulbs also indicate this
Leaves that are hard and upright, or skinny, or round in cross-section often indicate that the plant comes from a high light, exposed environment

28. Leaf nothing to chance! Leaf shape can also give cultural clues:
Leaves that are flat and wide often indicate that the plant comes from a lower-light environment
A lack of obvious pseudobulbs in sympodial orchids is an indicator that the plant likes consistent moisture

29. Fertilizer
Weakly, weekly (half-strength in summer, quarter-strength in winter)
Balanced water-soluble fertilizer ( with micronutrients, ideally with added Ca and Mg)
Should be orchid fertilizer, and never apply fertilizer dry

30. Fertilizer Blossom booster? Supplementing Ca, Mg Deficiency signs:
N: old leaves turn yellow
Ca: new growth turns black (looks like rot)
Mg: interveinal yellowing of old leaves

31. Fertilizer
Orchids have different fertilizers needs depending on type and season
Good rule of thumb is that the longer the root tips, the faster they are growing and the more fert they can use
Take-home: It is better to under-fertilize than to over- fertilize, orchid roots are very susceptible to fertilizer burn

32. Growth stimulants
There are many growth stimulant formulations out there
Must be fresh
KelpMax from First Rays, llc the best

33. Humidity Most orchids will grow best in 40%-60% humidity…
… but we live in Colorado!

34. Humidity (solutions) A small humidifier can be set up near the orchids
The plants can be set in trays or dishes with gravel or LECA as long as the water level doesn’t reach the pots
Plants can be grouped together to increase the humidity locally

35. And Temperature Temperature is an often-overlooked aspect of culture
Plants are physiologically geared toward certain temps
Air movement and adequate humidity can help, but…
(Masdevallia story)

36. And Temperature
Orchids are typically classified as either cool-, intermediate-, or warm-growing
Most orchids available here are intermediate or warm
Baker culture sheets

37. What grows well here?
Answer: Most orchids can be grown here, but some are easier than others Sometimes plants that “can’t be grown here” will do just fine if no one tells them that…

38. What grows well here?
Hybrid Phalaenopsis-

39. What grows well here? Phalaenopsis care:
Evenly moist, moderately bright (east exposure is at the upper limit)
Do well in sphagnum and bark
Not too particular about humidity

40. What grows well here?
Neofinetia Hybrids-

41. What grows well here? Neofinetia Hybrid care:
Evenly moist, very bright (east ideal, or protected from a south or west exposure)
Do well in sphagnum (clay pot)n or bark (plastic pot)
Like at least 40%-50% humidity

42. What grows well here?
Dendrobium Hybrids

43. What grows well here? Phalaenopsis-type Dendrobium care:
Allow to dry between waterings, very bright (east ideal, or protected from a south or west exposure)
Do well in medium bark (clay or plastic, water accordingly)
Like at least 30%-40% humidity

44. What grows well here?
Cattleyas-

45. What grows well here? Cattleya care:
Allow to dry between waterings, very bright (east ideal, or protected from a south or west exposure)
Do well in medium or coarse bark (clay or plastic, water accordingly)
Like at least 50% humidity

46. What grows well here?
Many other orchids will grow well in Colorado if their needs are understood
An understanding of the habitat and its seasonal changes are vital to success
Baker Culture Sheets are very useful in determining things like light, water, and temperature needs

47. Common problems (insects)
Know your enemy: Just as understanding orchids’ life cycles will help you keep them alive, understanding pest life cycles will help you eradicate them

48. Common problems (insects)
Homemade bug spray: 1 pint 70% isopropyl rubbing alcohol 1 pint 409 household cleaner water to make a gallon Mix in a gallon jug and spray every five to seven days until controlled

49. Common problems (insects)
Scale insects: sucking insects, females live under a shell
Treatment: Q-tip and rubbing alcohol,
insecticidal soap, systemic insecticide

50. Common problems (insects)
Mealy bugs: soft-bodied sucking insects
Treatment: Q-tip and rubbing alcohol, insecticidal
soap, systemic insecticide (make sure to
drench media; they like to live in the pot)

51. Common problems (insects)
Thrips: tiny, winged insects with rasping mouthparts
Treatment: Insecticidal soap, sticky traps reduce numbers, systemic insecticide (make sure to drench media; they like to live in the pot), requires vigilance and repeated applications, very difficult to eradicate

52. Common problems (insects)
Aphids: small sucking insects
Treatment: Strong jet of water, insecticidal soap,
or systemic insecticide

53. Common problems (mites)
Various mites infest orchids, populations tend to explode in hot dry conditions
Treatment: Spray leaves regularly, insecticidal soap,
or systemic miticide

54. Common problems (rot)
Crown rot: Happens when water sits in apex of plant Treatment: Prevention! Hydrogen peroxide or cinnamon are both antimicrobial agents, and may stop the infection

55. Common problems (rot)
Root rot: Happens when plant is overwatered, or not repotted in time Treatment: Prevention! Timely repotting and proper watering will prevent root rot

56. Common problems (Virus)
Virus: Several viruses infect orchids, and cause unsightly damage, slow growth, and death Treatment: Prevention! There is no cure for orchid virus, so the best thing to do is toss it

57. Common problems (cultural)
Floppy leaves: Can be from over- or under-watering Treatment: Check out roots

58. Additional Resources
Denver Orchid society: A great place to get learn about orchids! Our monthly meetings have presentations by experts from around the country (and world), and the opportunity to buy plants not available locally!
American Orchid Society: Membership in the AOS gets you free entry to many botanic gardens around the country, and you get Orchids magazine every month. It is another great way to connect with the orchid world and gain knowledge.
Understanding Orchids by William Cullina: An excellent orchid book, full of useful information on orchid culture and species.
Orchid Species Culture: Margaret and Charles Baker wrote culture sheets for an astonishing amount of orchids, I use these regularly when dealing with new species.