Rotted new growths on cymbidiums

[orchidgiants]

Thanks for all the responses and greetings!

I've picked up a few pieces of bark and can see healthy roots heading down into the bark, so I think I will not take it out of the pot just yet.

The Bayer All In One does have a fertilizer in it - it is 9-14-9. We only use that once every 6 - 8 weeks, and we find it controls scale, which we have in the yard environment, but has not harmed any plants that we know of. We use it on indoor masdevalias as well to control mealy bugs that pop up every so often. But now that you mention it, we've had some rotted new growths on one masdevalia too, so maybe there is a connection to the Bayer!?!? On the other hand, we're new to masdevalia's and still figuring out how to care for them, so it could be us. Or it could be that the Bayer affects new growths on plants that are overall still young (as opposed to new growths on older, well-established plants). As far as we know, it has not harmed any of our other cyms that we use it on.

During this growing season, we've been feeding the cyms with GrowMore brand 30-10-10, half the recommended strength, every 2 out of 3 waterings. When it is very hot, we lightly water the cyms once or twice during the week as well (extra waterings with plain water). Des - Why would we want to feed it with a lower nitrogen fertilizer now, during the grow season? (We have 20-20-20, Urea free 20-10-20, and Schultz 19-31-17 in the cabinet for other uses, but we've been using the 30-10-10 just during the active grow season on the cyms for a few years now).

We've never used hydrogen peroxide in the water, but may give it a try. Des - can you recommend a good contact fungicide? We thought the Bayer would take care of most bacterial and fungal infections systemically, but perhaps we should switch to a contact fungicide instead.

Whenever we do "surgery" on one of our plants, we dust the wound with sulfur. Orchids3 - Is the cinnamon recommendation doing basically the same thing?

We have:
Cymbidium (Dag 'Lollipop' 4n x Wakakusa 'Pearl' 4n) 'Stirling'
Cymbidium Ivy Fung 'Portwine'
Cymbidium Point Conception
Cymbidium Wallguard 'Alice'
Cymbidium (Lemon Butter x Golden Elf)
and 5 or 6 unknowns that we've picked up here and there.

[Des]

[QUOTE=orchidgiants;243301]Thanks for all the responses and greetings!

Des - Why would we want to feed it with a lower nitrogen fertilizer now, during the grow season? . Des - can you recommend a good contact fungicide? We thought the Bayer would take care of most bacterial and fungal infections systemically, but perhaps we should switch to a contact fungicide instead.


My summer fertilizer has a 16% nitrogen content and I also foliar feed during warm nights with a seaweed fertilizer Fungi seem to enjoy a high nitrogen on your leaves and will initiate on a temperature drop especially if you still have water down the axle of the new growth.
We have cold snaps here even in mid summer which can play havoc especially with your Cymbid seedlings.
I try not to use a systemic product unless it really necessary, as it can result in crippled flowers .
I use Captab and dithane alternativly, evey two weeks as part of my prevention program it makes for cleaner leaves and fewer problems

[orchids3]

It may have something to do with the type of Nitrogen. To me Nitrate and ammonia based fertilizers are much preferred by me personally. Some good growers might not agree - but urea based fertilizers require break down to urea or ammonia by Microbes - microbes is what sticks out to me. Also make sure that you get good airflow around your cymbidiums. I block off my shade house in the winter time so that I can prevent freezing with a water mist. I didnt remove part of the blocking fabric on one side this spring and developed a few problems that look a lot like yours next to the area that wasnt getting good airflow -

[Cym Ladye]

Orchigiant,

Rotting of new growths may be caused in several different ways. All cause moisture of one make-up or another to linger in the base of a fragile new growth, allowing for perfect conditions for growth of a fungal infection which then will destroy your new growth.
1) Watering late in the day with no wind and low temps.
2) Allowing pesticides/fertilizers to linger in the new growth more than 4-8 hours
3) The leaves on some tetraploid seedling growths, usually unbloomed, are so tight that it is virtually impossible for water to drain out, no matter the temp, time of watering or wind. I have experimented with a seedling now for 6 years. Just when it stopped rotting the new growths, a squirrel got the most recent one! Now I will try again. Roots are not the problem.

After cutting the rotten part out, I treat with cinnamon. To prevent, tip the plant after watering so that all water drains from the growths. Also be certain that the plant is in a warmer and or sunnier spot in your growing area with plenty of air circulation.

I also would not use the Bayer all in One as I suspect it is too strong for many orchid varieties and most certainly the new growths.

Good Luck,

CL

[orchids3]

Oh yes-another thing I thought of when I was reading another forum- keep the pH neutral for cym's
I like 7 if I can get it. Dont put Acid solutions (less than pH 7) on your plants.