Orchid disease/pest?

Asked February 23, 2019, 3:14 PM EST

Hi, I was given an orchid as a gift. Just noticing that the roots are now mottled white. The ones that I clipped in the photo were above the pot but all of the roots look like that now and they didn't when I received it. I just looked online at a few orchid sites and couldn't find anything that looked similar on the roots. I have been watering it about every 1-1/2 to 2 weeks by pouring water in the bark medium about 10 times or so and then tilt it so it drains well. It has been located on a south facing table with filtered light and I have had it sitting up above a dish of water, not touching the pot for humidity. It has not been in direct sunlight. Some of the leaves are facing downward too. What is the problem and what can I do? Thanks for looking.

Minnesota orchids

2 Responses

I would guess that the orchid is getting overwatered. When that happens the growing material can start to breakdown and cause issues with the plant roots. I am going to include some links below, in the orchid pests and diseases pdf, check out fungal root rot. If this is what you're seeing.

I would also water with filtered or distilled water - softened water can cause salt build up and cause issues with your plant.

I will also include some good links for orchid care.

http://www.phelpsfarm.com/OrchidPestsandDiseases.pdf
http://www.aos.org/orchids/orchid-pests-diseases.aspx
http://www.aos.org/orchids/orchid-care/orchids-101.aspx


Some more information from a Master Gardener colleague: The dots are sometimes described as pores, but they are normal part of the velamen (outer skin of the roots) and are used by the plant to take up nutrients. When dry the whole root will be whiteish, so this usually isn’t noticed until the roots dry a little. So, when wet the roots are green and when dry they are white. Sometime between these stages the spots are noticeable. I don’t know what her house is like, but watering every couple of weeks usually isn’t enough and is likely why her plant is droopy. I need to water my orchids more than that here in Florida, and they are outdoors in humidity that regularly exceeds 95%. I have a few hundred orchids, so I would love to be able to go two weeks between waterings. This plant looks plenty wet, so hopefully it hasn’t been in a cache pot or somewhere where it was sitting in water, but was just watered for their photo op. They should dry out between waterings. Happy leaves are more upright. She should water (with good water - not hard water or water-softened water. Melted snow or rain is fine. Soak the plant for a few minutes until the roots are green, then drain off the water and wait until they turn white to do it again. Under-watering and over-watering look the same (since they both cause the plant to not be able to access the water), but this is likely under-watering.