Leaves with black rot - Orchid Board

kp53 · #1 12-19-2021, 01:28 PM

Hi, is it better to cut entire leaf off that has rot or just cut the rot out?

SouthPark · #2 12-19-2021, 01:45 PM

kp ------ show some nice resolution pics first. And also mention - if possilble - what sort of orchid it is.

And also let us know if you have any sorts of treatments for rot - such as commercially available ones.

And also what sort of growing conditions? Pics of the setup and also details of growing conditions may help with recommendations about what could be done to maybe significantly reduce the chance of leaf rot.

kp53 · #3 12-19-2021, 02:40 PM

I’m trying to upload photos and I’m not being successful. The photos are in my gallery but not in my thread.

estación seca · #4 12-19-2021, 04:10 PM

Which gallery? When I go to the OB gallery I don't see anything with your username.

Sorry if this is too elementary - have you looked at this thread?
Tips for posting Photos

SouthPark · #5 12-19-2021, 04:45 PM

ES ..... I can see it at this link.

KP ----- it looks like you don't need to cut anything out. But maybe a good idea to apply some copper spray (for plants/orchids) on the leaves and stem only. Eg. fill up a hair-dresser atomiser spray bottle with the blue 'liquid' copper sulphate solution. And mist the leaves and stem with it. And then tilt the plant over a bit to allow any trapped liquid to drain out of little nooks and crannies - to avoid crown rot.

And then allow the leaves to do some natural air drying.

Also - if you happen to have any 'systematic' fungicides, then let us know what you have too.

Roberta · #6 12-19-2021, 06:22 PM

To me those spots look like old damage. if they don't spread, then you don't have to do anything. One way to get a better sense of whether they are spreading or not is to make a circle with a Sharpie marker around them. Then just observe for a week or so.

But don't cut anything for now, and if you need to excise a specific area you want to leave as much good leaf as possible But likely no treatment will be needed at all.

estación seca · #7 12-19-2021, 06:23 PM

Something injured the leaves, then damage spread. It could have been insect damage, like mealy bugs or scale. Or it could have been a biting insect passing by. Cold damage can start out as a single sunken dead area. Did it spend any time outside? Did any droplets of cold water land on the plant?

The leaves have a lot of discoloration. It could be cold damage, insufficient minerals or spreading damage from the injury.

What are your temperatures? How have you been feeding this plant? Is it getting magnesium, iron and calcium?

kp53 · #8 12-19-2021, 07:04 PM

The plant was outside for the summer. I know it got too wet several times. Sadly, I haven’t been fertilizing as I’m not sure what I should be using and how to apply it in the most efficient way. I should add that I’m in a wheelchair. Thanks for all the information.

SouthPark · #9 12-19-2021, 08:03 PM

Quote:

Originally Posted by kp53

Sadly, I haven’t been fertilizing as I’m not sure what I should be using and how to apply it in the most efficient way.

I don't use a precise way of making up my fertiliser. I just read the bottle for a particular sort of plant - such as 'orchid' or 'ornamental' ------ and then I see how much they recommend. And I then divide their 'recommendation' by 3, or even might divide by 4. And and I use this weakened amount.

In solution form ----- I can just put the solution in a spray bottle, and then spray into the media. I just do this once a month in my regular potted orchids with scoria media.

If using a watering can for watering ----- then just use the watering can. Just depends on how we water.

I also use something else --- usually a couple of weeks after the fertiliser application ----- which is applying magnesium-calcium in solution (ie. aka 'mag cal' or 'cal mag' application). I use a 'weakened' amount too for mag cal applications. It's not precise, but works just fine for me.

Roberta · #10 12-19-2021, 08:51 PM

Quote:

Originally Posted by kp53

The plant was outside for the summer. I know it got too wet several times. Sadly, I haven’t been fertilizing as I’m not sure what I should be using and how to apply it in the most efficient way. I should add that I’m in a wheelchair. Thanks for all the information.

Orchids don't need much fertilizer since they grow so slowly A little would be good.. the common "wisdom" is once weekly, weakly... Take whatever it says on the bottle (a balanced fertilizer with all numbers the same is a good place to start), use 1/2 to 1/4 as much . So it it says 1 teaspoon per gallon, use 1/2 to 1/4 teaspoon per gallon. If it gets to every 2 weeks, that's OK too. Get the rest of the culture correct, then that little bit of fertilizer will help the plant to thrive. Ask 5 orchid growers their opinion about fertilizer and you'll get 8 opinions.... endless arguments. The fine points can make a difference if you are growing commercially, or aiming for perfection of plants and flowers. For a beginner, I suggest ignoring the noise...