Seedling medium - Orchid Board

jaxorchidman · #1 10-12-2009, 04:17 PM

Curious if anyone has used vermiculite or pure perlite as a compot medium and as to which they found to be better?? I'm about to deflask some seedlings and am getting everything together. My setup will be some shallow trays with either of said medium in a fish tank with a heat mat under the pots. plan on using physan 20 and captan to dampen off the little ones. I also have a 15W bulb in the aquarium that is made for aquariums (water plants). Any help is very much appreciated!!! Thanks!!!

Des · #2 10-12-2009, 04:45 PM

Perlite mixed with CHC is good .I have always found it very important when deflasking seedlings to ensure that both the media and the the feed water is sterilized . Failure to do this will cost you plants. Also ensure that the ph of both water and meadia are 6 to 6.5 . What seedlings are you deflasking ?

jaxorchidman · #3 10-12-2009, 04:48 PM

I plan on feeding with distilled water that has small amount of captan and physan 20 in it. maybe second month I will start adding small amounts of fert. to it. I'm still not sure, but that's how you learn right???

jaxorchidman · #4 10-12-2009, 04:48 PM

What is CHC Des??? Coconut husks??

Des · #5 10-12-2009, 05:16 PM

Quote:

Originally Posted by jaxorchidman

What is CHC Des??? Coconut husks??

Thats right coconut husk chip I use the small chips with the fiber for Cymbidium seedlings My brother adds perlite .I cant get perlite here

Undergrounder · #6 10-12-2009, 05:20 PM

jax what seedlings are you planning on deflasking? The extra humidity of the tank might be good for some, un-needed for others and lead to fungal problems in yet others.. a small fan on a timer might be needed to combat fungal problems if you insist on using a closed tank.

I have had superb results using pure coarse perlite (the coarser the better) as a deflasking medium. Sit the compot in a shallow tray of water to keep the perlite constantly wet for best results.

Add a top-dressing of small rocks/pebbles to keep the wet surface of the perlite free of algae and away from the leaf and crown area of the plant.

The water is plain tap water, not distilled or sterilised. In fact when i haven't bothered to clean the reservoirs for a long time they're more a thriving algae farm than a dish of water. With no problems for the plants. My tap water is actually quite alkaline. I add fertiliser at about 150ppm after about 3 months and that brings pH back down to 6.5 or so. Captan or Physan might be a good idea down the track, but in the 2 years of growing in perlite so far i haven't had problems with water-born pathogens.. the occasional crown rot possibly from pseudomonas in small and weak seedlings, but only occasionally, never spreading, and never in healthy seedlings..

I DON'T reccommend vermiculite, it compacts way too easily and isn't really coarse enough, holds far too little air.

I don't reccommend CHC with perlite because the CHC tends to discolour the perlite brown, it decays slowly and is just not needed. In a test with both, i found better results in the ones with straight perlite. That's my experience of CHC/perlite mixes anyway.

jaxorchidman · #7 10-12-2009, 05:21 PM

Anybody used vermiculite??? I figured that since it was a sterile product it might work. It retains moisture well too!!

jaxorchidman · #8 10-12-2009, 05:29 PM

Thanks guys!!!

Under- The flask is Lc. Gold Digger X L. tenebrosa. I'll stick with the straight perlite. I have rigged a computer fan to move the air around and am going to put it on a timer. Thanks a lot for the info!!!

Des · #9 10-12-2009, 05:35 PM

Different strokes for different folks I guess , But I do agree with Undergrounder about the Vermiculite.
Sydney has a warmer climate so you might be lucky to get away without sterilizing .In Port Elizabeth if you dont sterilize you can kiss at least 50% of your seedlings goodbye.

Undergrounder · #10 10-12-2009, 05:42 PM

jax i don't have direct experience of deflasking cattleyas, but i am not sure the extra humidity would be needed. It might, depending on your ambient humidity, i'm just not sure. I get a stable 60% most of the year, dropping lower in winter and higher in summer. Only certain species and hybrids with certain species in their background will show initial dry leaf or leaf die back in those conditions.

Just keep an eye on them and increase/decrease the fan timing as necessary.

I add some pics as well just to show you that perlite works well. I know Des has a lot of experience deflasking Cyms so i wouldn't disagree with his requirement for sterilising the water in his conditions and using his methods. I do it indoors, so that might be a factor. Temps recently drop to a minimum of about 14degs C for a few hours at night, and then back up to a stable low 20degs C. In summer they clime to mid 20s, and because i use fluorescent lights which are in effect bottom heating, it can clime into the 30s in summer. They get great growth rate then.

Also as i mentioned because the water wicks water extremely well, i always water from below, and never get leaves wet. In all my clone flasks i have close to, if not 100% survival rate. The occasional death is almost always from crown rot due to pseudomonas attack in poor growing seedlings. Root rot is never a problem, leaf spot is never a problem. If i could get Captan or Physan i probably would use it in the water though. I just haven't found a good alternative here in Aus.

P.S. Des i recently tested a pot of deflasked Cym clones in pure perlite, they busted out great with 100% survival. The only problem was after they outgrew their pot i put them in 100% CHC outside and they slowed down a lot, although i treat them as garden plants outside they get very little help.