Seedling mix question.

[King_of_orchid_growing:)]

I actually do not know if there is a technical term for the transition from vine-like seedling to a seedling with pseudobulbs. That would be interesting to find out if there was one!

I'm sorry, but I'm not quite understanding your question about balancing the pots between too little and too much humidity. What is the issue that is prompting you to ask this question? Can you maybe ask the question again in a different way?

[bil]

Originally Posted by King_of_orchid_growing:)

I actually do not know if there is a technical term for the transition from vine-like seedling to a seedling with pseudobulbs. That would be interesting to find out if there was one!

I'm sorry, but I'm not quite understanding your question about balancing the pots between too little and too much humidity. What is the issue that is prompting you to ask this question? Can you maybe ask the question again in a different way?

OK. It it blatantly obvious what happens if they are not moist enough. They dessicate and die.

My question is, can you err too much on the side of too humid?

[bil]

Or I suppose I could put it thus, with a vented hood, how vented does it need to be?

[King_of_orchid_growing:)]

I see.

Ok, like I said before, the best thing to do is not to use a pot. I recommend using a tray and using a vented dome. It is not convenient to use a pot. There was actually someone on Orchidboard from several years ago who had tried getting Coryanthes seedlings and she had to use a basket to accommodate them. This has been my experience as well, so I recommend using a tray, not a pot.

Initially upon deflasking, humidity has to be high. I would only crack the vent on the dome open a little bit. If you had the domes with two vents, I'd only open up one of the vents and only by a little.

Open up the vents a little bit more one week at a time.

Over time you will see which ones will make it, and which ones will not. The next few things I say are difficult to verify scientifically, and I might be wrong about this, so I encourage you to make your own judgements on the following advice. I've found that once you discover a seedling that will not make it, discard it immediately. Do not allow them to stay in the container for too long. It might cause the other seedlings significant amounts of stress. Remember, they can chemically sense their surroundings and they can communicate with each other chemically. I find that the quicker you remove dead seedlings, the less likely the other seedlings are going to get stressed. I have found that the longer a dead seedling remains in the same container, the more likely the other seedlings will come down with problems as well. Like I said, it is difficult to verify without scientifically conducting some serious experiments the average home grower has no way of performing, but I am currently working with seedlings from different species of orchids. I have found that when there was a larger number of seedlings that were dying off left amongst the other well-to-do seedlings for a period of time, more seedlings proceeded to die. As soon as I removed as many of the dead seedlings as possible upon every check, significantly less seedlings died as time progressed. This is what you want. You want less and less of the seedlings to die. Death of seedlings is inevitable. It is a numbers game. 100% survival or even 80% - 90% survival rates are not common. Can it happen? Yes, if the deflasked orchids were grown in flask for several years and the seedlings you get are very large and sturdy, particularly if they are from a sturdy species such as Cattleya.

[bil]

Originally Posted by King_of_orchid_growing:)

I see.

Ok, like I said before, the best thing to do is not to use a pot. I recommend using a tray and using a vented dome. It is not convenient to use a pot. There was actually someone on Orchidboard from several years ago who had tried getting Coryanthes seedlings and she had to use a basket to accommodate them. This has been my experience as well, so I recommend using a tray, not a pot.

Initially upon deflasking, humidity has to be high. I would only crack the vent on the dome open a little bit. If you had the domes with two vents, I'd only open up one of the vents and only by a little.

Open up the vents a little bit more one week at a time.

Over time you will see which ones will make it, and which ones will not. Although it is difficult to verify scientifically, and I might be wrong about this, so I encourage you to make your own judgements on the following advice. I've found that once you discover a seedling that will not make it, discard it immediately. Do not allow them to stay in the container for too long. It might cause the other seedlings significant amounts of stress. Remember, they can chemically sense their surroundings and they can communicate with each other chemically. I find that the quicker you remove dead seedlings, the less likely the other seedlings are going to get stressed. I have found that the longer a dead seedling remains in the same container, the more likely the other seedlings will come down with problems as well. Like I said, it is difficult to verify without scientifically conducting some serious experiments the average home grower has no way of performing, but I am currently working with seedlings from different species of orchids. I have found that when there was a larger number of seedlings that were dying off left amongst the other well-to-do seedlings for a period of time, more seedlings proceeded to die. As soon as I removed as many of the dead seedlings as possible upon every check, significantly less seedlings died as time progressed. This is what you want. You want less and less of the seedlings to die. Death of seedlings is inevitable. It is a numbers game. 100% survival or even 80% - 90% survival rates are not common. Can it happen? Yes, if the deflasked orchids were grown in flask for several years and the seedlings you get are very large and sturdy, particularly if they are from a sturdy species such as Cattleya.

Damn, but this is interesting. I really appreciate you taking the trouble to explain it all.
My apologies if I ask too many questions, or repeat any, I know that can be irritating, but I would like to get this right.
OK; so a tray, not a pot. How deep would you fill it, and when you lay the seedlings on it, would you make any attempt to cover the roots with moss. Also how far apart would you put them?

Re plants communicating. I remember my bio teacher telling us that if you grew a single species of grass in a tray, you would get tall, medium and small plants. Then, if you replanted them, so you had one tray for the small, one for medium and one for large, the plants would chang till you ended up with three trays all with mixed heights.

[King_of_orchid_growing:)]

Originally Posted by bil

Damn, but this is interesting. I really appreciate you taking the trouble to explain it all.
My apologies if I ask too many questions, or repeat any, I know that can be irritating, but I would like to get this right.
OK; so a tray, not a pot. How deep would you fill it, and when you lay the seedlings on it, would you make any attempt to cover the roots with moss. Also how far apart would you put them?

Re plants communicating. I remember my bio teacher telling us that if you grew a single species of grass in a tray, you would get tall, medium and small plants. Then, if you replanted them, so you had one tray for the small, one for medium and one for large, the plants would chang till you ended up with three trays all with mixed heights.

Fill the tray with moss that is not too thick. A thin layer should suffice. Only enough to cover the bottom of the tray should be fine.

Do not attempt to cover the roots. They are too small and fragile to do so.

As far as spacing goes, space them out according to how you feel is convenient for you. You don't want to bunch them up too much or it will get frustrating. If you space them out too much, you're wasting space. You're the one with the seedlings, you have to feel it out on your own.

Once you deflask your seedlings you will also get an array of sizes, including protocorms. I have never had a protocorm that was grown in-vitro survive ex-vitro, so discard those immediately. I imagine the same scenario happening to the orchid seedlings if you did what your bio teacher described. I have never received seedlings of uniform size in a batch. They're always of varying sizes and stages of development. I don't believe it is possible to obtain a homogenous batch of seedlings. Homogeneity of seedling size and development may not be very realistic whatsoever.

---------- Post added at 07:36 AM ---------- Previous post was at 07:16 AM ----------

Actually, now that I think of it...

If you find any protocorms in the flask, do not open the flask. Find a local orchid seed sowing lab who is willing to work with you. You can send the flask to the lab, and ask them to separate out the protocorms from the rest of the seedlings and just send you the seedlings and pay the lab for replating the protocorms if they allow you to do so.

If no labs are willing to help you in this regard, you can replate the protocorms yourself and deflask the seedlings that are large enough to grow out if you have access to a university's fume hood and lab.

[bil]

Originally Posted by King_of_orchid_growing:)

Fill the tray with moss that is not too thick. A thin layer should suffice. Only enough to cover the bottom of the tray should be fine.

Do not attempt to cover the roots. They are too small and fragile to do so.

As far as spacing goes, space them out according to how you feel is convenient for you. You don't want to bunch them up too much or it will get frustrating. If you space them out too much, you're wasting space. You're the one with the seedlings, you have to feel it out on your own.

Once you deflask your seedlings you will also get an array of sizes, including protocorms. I have never had a protocorm that was grown in-vitro survive ex-vitro, so discard those immediately. I imagine the same scenario happening to the orchid seedlings if you did what your bio teacher described. I have never received seedlings of uniform size in a batch. They're always of varying sizes and stages of development. I don't believe it is possible to obtain a homogenous batch of seedlings. Homogeneity of seedling size and development may not be very realistic whatsoever.

Boy oh boy. I am really getting the impression that I have somewhat stuck my neck out on this. Still, there's no learning without trying something new. If I do get any to grow, it will certainly be thanks to all the advice so freely given.

I'll let you know how I get on with them, and if I have any more questions, you'll be the first to know!

Thanks again for the help.

[Roberta]

You picked a particularly challenging group to start with! When fall comes, they may or may not think about dormancy. Having tried and failed, I can only pass along the advice that I received, to keep on watering, don't dry them out at the time that they might otherwise be expected to go dormant. When the time comes, you may wish to seek the advice of Fred Clarke at Sunset Valley Orchids - he specializes in this group of orchids.

[bil]

Originally Posted by Roberta

You picked a particularly challenging group to start with! When fall comes, they may or may not think about dormancy. Having tried and failed, I can only pass along the advice that I received, to keep on watering, don't dry them out at the time that they might otherwise be expected to go dormant. When the time comes, you may wish to seek the advice of Fred Clarke at Sunset Valley Orchids - he specializes in this group of orchids.

OK, thanks for that..

[King_of_orchid_growing:)]

Worry about dormancy after you start seeing pseudobulbs and more vigorous root growth. In the meantime, when they're still tiny vine-like plants, just focus on keeping the moss damp until you see pseudobulbs. Do not ever keep the moss sopping wet.