LOts of root growth, not many leaves
Several months ago (probably close to a year ago now) I ordered some cuttings SRQ Hoyas, and have been absolutely thrilled with the service, and their overall health. They have rooted extremely well, possibly too well.
To start with, I have them (at this stage, just cuttings, not big yet) in a terrarium. Each is potted individually in a somewhat coarse Hoya mix, (Recipe Courtesy of vermont Hoyas website) Each small pot (2-3") has one small plant in it. Between the pots, I have added sphag to help keep the humidity high. The problem that I am having now, is that the roots have gone through the bottoms of the pots, through the drainage holes, and into the sphag. These plants are producing colossal amounts of roots, but I see very little growth topside. No new leaves or shoots on any of the Hoyas, except for one: H. naumannii, which has practically exploded. The other two (Macgillivrayi "pandanus creek" and Mathilde) Have not set a single new leaf or tendril, even though they have rooted all over the place.
The humidity is high (usually over 75%), and the temp in the terrarium averages 74Ã¯Â¿Â½F, with a cooler nighttime. It is lit with a fluorescent bulb that is run on a timer.
I mist the terrarium as needed with distilled water to keep the glass clean, and the humidity high. Usually every other day or so. I water the plants directly with dechlorinated tap water and fertilize with water from my fish tank.
What can I change to encourage them to grow more leaves and tendrils and start progressing upwards?
Do the roots need to be contained for this to happen?
The only real problem I have with them is that they require a lot of trimming to keep them from rooting to eachother, and other pots in the terrarium.