Different light needs?

[Dimples]

Originally Posted by Ray

Possibly, but if you consider the dust-like qualities of orchid seed, who's to say where they end up!

Very true, but if they end up germinating in a highly exposed location, perennial seedlings are far less likely to survive to maturity unless environmental conditions are perfect or near-perfect for the first few years. It's much easier for a tiny to mid-sized, wild sown, perennial seedling to survive heatwaves, droughts, or unusually cold temps (compared to what the species is adapted to) when surrounded by larger plants of any type to buffer the extremes.

Annual plants are a different story. They'll grow and set seeds anywhere they land. I haven't had to plant or tend cilantro, nasturtium, calendula, sunflowers, or dill in years! LOL

[Roberta]

I would give them all the same duration of light Yes, a little less intensity for the seedlings... Now that spring is approaching, consider starting to acclimate them to more light (gradually) 75% is pretty dark for a Catt. As for the larger ones being "asleep", Catts don't have dormancy. But they have different seasons for both growing and rooting, which is why you have to observe them.

We have had some cold nights recently, but within a couple of weeks, nights should be warm enough to start moving things outside. Best to acclimate things slowly.. light especially can increase suddenly this time of year (leading to toasted leaves if they aren't adjusted gradually)

[isurus79]

I grow my seedlings next to my adult Cattleyas and they receive the same amount of light for the same duration.

I'll also add that 75% shade cloth is pretty dark, especially this time of year. What part of the country are you growing in?

[Roberta]

Originally Posted by isurus79

I grow my seedlings next to my adult Cattleyas and they receive the same amount of light for the same duration.

I'll also add that 75% shade cloth is pretty dark, especially this time of year. What part of the country are you growing in?

RoseSD is in the San Diego area I am not far away.. that is why I use my environment as a pretty good approximation for hers as a reference point. Where I live, 75% is barely adequate for Paphs. Hence my additional suggestion... start acclimating the Catts to higher light NOW - we do get some clouds, sun is not that intense, After the equinox the sun starts to clear buildings and trees suddenly, it's the time of year where I have toasted more leaves than any other ... time to avoid surprises. Forecasts have nights near or above 50 deg F (10 deg C) within the next week, and going forward. Wouldn't move the Phals out for another month or two but practically everything else is a candidate.

[estación seca]

Seedlings are at much higher risk of severe damage from sunburn than are adults, so I give them less light. Sunburn is a real problem here in Phoenix, and I would think San Diego too. Catts grow well with less light but they don't flower well. Seedlings aren't going to flower so I prioritize preventing sunburn.

[Roberta]

If "two years old seedlings" mean 2 years in the possession of the OP, they're not babies anymore.
So it also depends on how well established they actually are. 2 years out of flask is still fairly young, but 2 years after purchase add another year or two to their actual age and they aren't really "seedlings". That isn't clear from the post.

[RoseSD]

Photo might help?
Large, medium, small. 😁