Ludisia discolor (in all of its variants) is probably the most forgiving of the jewel orchids, as it will grow well in long fiber sphagnum, constantly moist bark mixes, coco husk chips (and/or fiber), soil mixes, and a variety of others. The great thing about Ludisia is that it is forgiving about being more damp than the others if you have a planting media that doesn't drain optimally (such as long fiber sphagnum, which can water-log).
However, other jewels are a little less tolerant of poor draining media. Anoectochilus and Macodes prefer slightly better aerated or drained media, but still prefer constantly moist conditions and high humidity (perfect for our dart tanks!). To increase aeration of the soil, an easy solution is to add activated charcoal to whatever mix you are using. I use a mix of 1/2 inch and 1/4 inch coconut husk chips with activated charcoal in an approximately 1:3:1 ratio for these plants. Additionally, if you are not using a false bottom system, make sure your water level is always below the root line (which is difficult to tell, because these things have a surprisingly large root system if allowed to grow freely for a long period of time.
Don't give up on these guys if they don't take off right away . . . they are slow growers. I love the jewel orchids, and I would suggest that anyone making an order from AJ Calisi at T&C Terrariums should buy one of his Macodes petola for $15. No, I don't get a kickback, but that's the cheapest I've seen it ANYWHERE (I paid $25 for mine at a local orchid greenhouse, and did so happily), and it is an absolutely gorgeous plant. Pictures really cannot do this one justice.
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Homer W. Faucett III, esq.
Purveyor of Trivialities and Fine Nonsense