Issues growing Slc Jillian Lee

[Paul]

Getting quite aggravated with this little bugger. I've had it at least 3 years now and it repeatedly aborts new growths though it keeps trying to put out new ones. New growths often get to be about an inch or two long before turning brown and dying. Doesn't matter what time of year. Catts are usually pretty brain-dead easy for me.

It only gets watered with RO water. It sits on a plant stand in front of my unobstructed SE sliding glass doors. Leaves are a medium green so I'm sure it is not a matter of too much sun. Summer temps can be in the 80s F by day and low 70s by night. Winter temps are typically low-mid 70s by day and upper 60s by night. It is potted in a mix of large grade coconut husk, charcoal, and hydroton. My other catts do just fine.

Anyone out there growing this one?

[Leafmite]

Maybe more calcium? Of course, I am paranoid about Calcium after losing most of my Cattleyas a few years ago to Calcium deficiency. The interesting thing? A few of my Cattleyas were not at all affected by the lack of Calcium.

[tucker85]

When new growth dies on cattleyas, it's usually a sign of calcium deficiency, like Leafmite said. If you're using RO water, you should be using a fertilizer that has calcium and magnesium. If your fertilizer doesn't contain cal/mag, you can use a cal/mag supplement. I use one called MagiCal from Technaflora. You can add one teaspoon to each gallon of fertilizer water or you can apply it separately at the same rate of one teaspoon per gallon.

[NYCorchidman]

Originally Posted by Leafmite

Maybe more calcium? Of course, I am paranoid about Calcium after losing most of my Cattleyas a few years ago to Calcium deficiency. The interesting thing? A few of my Cattleyas were not at all affected by the lack of Calcium.

I find that hard to believe!
The ones that were not at all affected, were they in different potting mix??

Unless the mix was somehow different in pH thus affecting the takeup of certain elements, or certain cattleyas are just crazy strong, I don't understand how that was possible.

Did you use the same mix and same water on all of them?

Also, I'm curious, how did your cattleyas die?
What did they look like?

I thought calcium deficiency shows up as black marks on the tender young growths.

[PaphMadMan]

There isn't anything unusual about the ancestry of Jillian Lee that should make it a difficult subject, assuming you have success with other Catts with C. (S.) coccinea background. Both of its parents are rather vigorous little primary hybrid weeds, and most mini-Catts are of similar ancestry.

The possibility of calcium deficiency should be investigated. Is it in different media than others? When did you last repot? Do you fertilize regularly? Does your fertilizer include calcium and magnesium?

Or you could just have a weak clone...

[bethmarie]

Don't know that it would have anything to do with the specific problem your SLC is having, but look out for pH when watering with RO.

The RO I use runs on the acid side to begin with. When I add fertilizer to it, it becomes acid enough to damage roots. Which it did, on my plants. I mix in about 20% tap now and check the pH if adding fertilizer. I often have to adjust the pH back up to the 6ish range, even with tap added in when I fertilize.

[PaphMadMan]

Originally Posted by bethmarie

The RO I use runs on the acid side to begin with. When I add fertilizer to it, it becomes acid enough to damage roots. Which it did, on my plants. I mix in about 20% tap now and check the pH if adding fertilizer. I often have to adjust the pH back up to the 6ish range, even with tap added in when I fertilize.

The initial acidity of RO water is somewhat misleading. Almost completely due to dissolved carbon dioxide from the air, it doesn't have much tendency to resist (buffer) pH change when other compounds like fertilizer are added, and the initial apparent acidity of the RO water doesn't really affect the final pH of the fertilizer solution much. RO water used for watering by itself (not recommended for more than an occasional flush) really has almost no affect on the pH of the media except by leaching out and washing away anything it can.

It is a good practice to check and adjust the pH when adding fertilizer, and some fertilizers are much more acidic than others. One that is formulated for use with rain water or RO water shouldn't end up too acidic to use if the concentration isn't extreme. But if the concentration is in the low range usually recommended for orchids and you flush out excess salts once in a while it won't change the pH of the media much. Many organic materials in orchid media have a large capacity to buffer pH to their own natural mildly acidic state. If your fertilizer is an unusually acidic formula or meant for use with hard (alkaline) water, or you use it at high concentrations or have salts building up in the media, or your media is entirely inorganic, then pH is a much bigger concern.