Culture of Catt. seedlings

[Rhonda Svoboda]

Hi all,
I am thinking about purchasing 2 Catt. seedlings, Cattleya leopoldii v. flammea, and Cattleya Tai Rose x bicolor. I am concerned about buying seedlings. Do they require different cultural practices?
Also, MI has a long winter and the temps in my home are around 70-72F with night temps around 60F. The leopoldii seems to require warm to hot conditions. Can I grow this under my conditions? I grow under lights Oct-Apr. Then the plants go outside for the summer.

[Roberta]

C. leopoldii (tigrina) warm to hot? I don't think so... that's one of my outdoor-growing Catts, so they do OK with winter temps down to 40 deg. F/4 deg C or occasionally lower. It is it ideal? Probably not but I have 2 plants that grow well and bloom well under those conditions. Your indoor temps are plenty warm for that species, it could even go cooler with no problem. The C. Tai Rose x bilcolor should also be fine.

[Rhonda Svoboda]

Yeah!! Thank you- do I need to grow seedlings differently than mature plants?

[Roberta]

Originally Posted by Rhonda Svoboda

Yeah!! Thank you- do I need to grow seedlings differently than mature plants?

I don't think so. Small plants may be less forgiving of "insults" than mature ones, but your conditions sound quite good.

[estación seca]

Depending on ambient temperatures, seedlings tolerate drying out poorly compared to adults. I try not to let any of my Cattleya seedlings dry out completely during warm weather. I have warm conditions in my sunroom all year, and Cattleya seedlings make new growth continuously for me. Many home growers have much cooler winter temperatures in their growing areas than I do. Bifoliate Cattleyas, like leopoldii, can be tricky if watered too much in cooler winter conditions. Nevertheless, I would not let a leopoldii seedling stay dry for more than just a few days in winter.

During warm, humid periods of the year, like your summer, they will grow amazingly fast and use a lot of water. My Cattleya seedlings that arrive in sphagnum moss use even more water than Oncidium mericlones of the same plant size that arrive in sphagnum moss.

As to fertilizer - on the Sunset Valley Orchids Web page Fred Clarke says he uses MSU type fertilizer at a half teaspoon per gallon of water, at almost every watering. His greenhouses are warm and humid, and this would not apply to somebody growing in a cooler environment, or with less humidity. Here is the quote:

Watering and Fertilizing are related, as water carries fertilizer into the root zone. Important for good Cattleya growth is to have their roots dry down between watering. I fertilize with every watering using a weak fertilizer solution of 100 PPM nitrogen; this equates to ½ tsp [COMMENT: MSU formula, about 2.5ml of powder] in a gallon [COMMENT: 3.78 liters] of water. In the summer when days are long and warm, the plants are in active growth, and photosynthesis is at a high rate I water more, usually 2 times a week. However during the hottest period I may water 3 times a week. During the cooler months watering once a week is generally satisfactory. Before watering I always check that the potting media has dried out sufficiently. Once a month I leach the pots where I water without fertilizer twice, one hour apart. This reduces any salt build ups.

[Shadeflower]

It really depends on what size the seedling is.

This cross will grow to be 2-3feet tall. The substrate you would use for a 3 foot tall Cattleya would most certainly differ from a 1 inch seedling.

The tall plant will have lots of roots, the seedling will have paper thin roots that would dry up in intense sun instantly.

The light requirement will be different. A lot is different, seedlings don't have a lot of energy reserves so if the seedling loses all its roots which will happen far easier as they are 100 times thinner then they can't just regrow them easily. Seedlings should not and do not need to be exposed to the same winter temperatures the mature plant might be able to handle.

To start with seedlings generally are quite time consuming keeping them watered regularly. As they get older and can handle lower humidity's the watering interval can be increased.

Treat a seedling like a mature plant and the seedling will most likely get dehydrated so yes it's different.

[Leafmite]

Nearly all my Cattleyas have been bought as seedlings, many very tiny seedlings, but I cannot really offer advice as I use red lava rock/basket pots and happily pot them up in a basket where they can grow for the next five years undisturbed (one cannot do this with bark) and be watered like crazy. I have never had any trouble with seedling orchids. As said, if they are very small, one needs to make certain they have plenty of humidity and water (without rotting the roots) as they don't have the storage system that a larger Cattleya will have. Good luck!