Various leaf problems - black spots, yellowing, scratches

[milkygato]

Hi all, my husband and I received some orchids for our wedding. We are both new growers and while I’ve done extensive research on growing orchids, there seems to be a lot of different information out there so I’m happy to become part of this community.

Our orchids all seem to be having different leaf problems that I cannot figure out the cause. Most of them are placed close to the window and receive indirect sunlight. I have a humidifier close by because it’s pretty dry where I live. 4 are planted in moss, two in bark, and I water them roughly every two weeks or so.

Please help me figure out why the leaves are this way. A couple of them have scratches/splits, some are yellowing, some have black spots =(

[Roberta]

First, Welcome, and congratulations on your wedding!

The scratches look like superficial mechanical damage. The dry black spots also look like old damage - soft spots are more of a concern. If you want to tell if a spot is growing, you can put a circle around it with a sharpie, and keep an eye on it. If the yellowing is a bottom leaf, likely to be force of nature... oldest leaves do eventually drop.

Now to look at the actual culture. If they're taking two weeks to dry out, that's a clear indication that they're badly in need of repotting. Moss is generally bad news... it is a perfectly good medium if it is fresh and you can gauge the watering needs. That being said, most people find it a lot easier to get the watering correct in bark. (Fresh bark... what you have is likely old and broken down) Orchids typically want "humid air" rather than "wetness" - they need to dry out a little beween waterings, because as water evaporates, it pulls air into the root zone. So, I suggest repotting all of them in medium-sized bark (pieces 3/8 to 1/2 inch is ideal) Then, you should water every 3 days or so (fresh bark dries fairly fast), water thoroughly. You can hold them under the faucet, let water run through the pot (flushes crud, pulls air into the root zone), drain well. If you lift the pots when they are freshly watered (or weigh on a postal or kitchen scale), then do it again in a few days. As it dries, it'll be lighter. After a while you'll get a feel for how often you need to water in your environment. For fertilizer (orchids don't need much but do need a bit) you can use whatever you use for other house plants, but use at half-strength, once every week or two. Too little is far better than too much. For a more extensive discussion, check out the "sticky" The Phal Abuse Stops Here .

[milkygato]

Hi Roberta,thanks for your advice!

I think I may have banged the leaves around a bit when I was watering them...Feeling slightly better about the yellowing and black spots now.

About your advice regarding repotting, my flowers are in full bloom currently and I read some articles that said not to repot unless absolutely necessary while the flowers are bloom. Being a novice, I don’t want to make the mistake of doing a bad job at repotting and killing all of the flowers. Do you think I should still try to repot them now instead of waiting?

Btw I love your garden! I am in Northern California so I have a lot to glean from your experience in caring for orchids in Californian weather.

[Roberta]

Phals actually are quite forgiving about being repotted in bloom...just be careful to not knock them around. If you decide to do it, don't worry about getting the last bit of old medium off - leave anything that is stuck on, just remove what's easy. A reason for not waiting on Phals - they can stay in bloom for months, and if the medium is bad, a lot of root rot can happen by the time the flowers fade. So depending on how bad it is, it may be worth risking current blooms (which very likely won't be bothered) for the long-term health of the plant.

The other thing about doing anything when they are in bloom, it's important to keep the plants oriented in the same direction with respect to light... they'll try to follow the light, and so if you turn them the spike will twist, making a less-attractive display.

Where in northern California are you? While most areas are significantly cooler than where I am, the coastal area, at least from San Francisco south, is not all that different, just a bit cooler in summer but winter (frost-free) is not that different.

[milkygato]

Great, I’ll try repotting them soon. Thank you so much!

I’m in San Jose so seems like we have a similar climate, although my orchids are the only plants around the house so it’s probably too dry for them.

[Roberta]

Don't worry about the dryness of the house.. but once you repot, you'll need to water more often because the fresh medium (bark is a good idea... easier to get the watering correct than with sphagnum, I think) will dry out much faster than the old stuff. Yes, San Jose is very similar to where I live. So if you decide to branch out into other orchids like Cymbidiums, the same things will grow outside. (Phals are indoor plants for sure... they like the same temperatures that we do)

[milkygato]

Once I get the hang of phals I’ll venture out to Cymbidiums =)

One quick question regarding repotting - what kind of bark do you use? Can you recommend a brand? And how to you water with bark, do you use the soaking method?

[Roberta]

I would go for a medium-sized bark (like maybe 3/8 to 1/2 inch size) if you can find it. Your odds are better at a nursery than a big-box home-improvement store. I like Orchiata... I have a nursery supplier not far from me that sells it. Of course, there's always the 'net ... you are close enough to Orchiata



– Flori-Culture: Orchid & Specialty Growing Supply (Sacramento area) that shipping isn't so horrid, but they seem to be out of the smaller quantities (and you don't need 40 L of it) Found this on Amazon Amazon.com that should be good and not too pricey. rePotme.com has some fancy mixes, again I'm not so sure that you need to go so fancy but it is good stuff.

For watering in bark, I would just put the plant under the faucet, let it run through the pot. Let drain, repeat in a few days. It is really airy.

Now, lots of people on the Board use the semi-hydroponic technique with completely inorganic media, with very good results. The idea is that you use a container that, instead of holes in the bottom, had a hole or two an inch or so above the bottom - fill it up, let drain. It holds humidity (that bottom inch or so serves as a reservoir, roots are well above it) Check out the semi-hydro forum for ideas, or Ray's website - he has done a lot of work with the technique. General Semi-Hydroponics™ Information › First Rays LLC

In all cases, the idea is to give the roots "humid air" rather than "wet".