I’ve read on here that changing anything for an orchid should really be done gradually and effects can only be observed on a yearly basis. It would make sense since cattleyas generally produce one new growth a year.
That being said, you mentioned you’re using two kinds of fertilizers. There’s a thread somewhere that I’m in where some fertilizer experts gave me a very complicated lesson on fertilizer. Here’s a link you should find helpful
Plant Nutrition
I’m only beginning to use fertilizers myself. There were some mistakes I’ve made before that ruined some roots and may have killed a few more. Blooming orchids don’t need fertilizer and same with orchids that are not putting out new growths. I would rather not use fertilizer at all instead of use too much.
But fertilizer aside, you might want to remove your orchid from bright light and put it in lower light as well. It is now an orchid in recovery and lower light is recommended. Much like a person who is recovering from an illness may want to eat bland easily digestible foods. Less water, less light, and no fertilizer. It’s possible your orchid may make a recovery. When my cattleyas aren’t doing well, I pray for a new growth so it can make new roots and have a better chance at survival.
Orchids aside, if you’re thinking of planting bamboo straight into your yard, I would recommend against it. I know a few neighbors who are having trouble keeping their bamboo under control in their yard. Those charming things can become monsters.
Hybrid Mode
