Fertilizer Change During Flower Spike

[Roberta]

Like everything else "orchid" the "right" answer is likely "it depends". There has been a lot of study on techniques to optimize growth and blooming for commercially-produced Phalaenopsis - it's a huge cash crop. Every factor (light, temperature, fertilizer formulation-concentration-frequency, water, and timing of variations in all of those) is optimized for that monoculture crop, The goal is to get lots of blooming plants to market fast, especially for flower-buying holidays.

For those of us who grow examples of the rest of the 800-900 orchid genera (not counting the human-made ones) under a range of conditions suitable to them and manageable for us, the "rules" that work for those mass-produced Phals likely are not appropriate in that broader "orchid world". It's both "less complicated" in that one can get very good results with less-than-optimum conditions, and "more complicated" in that different orchid types have different needs, often very different at different times of the year, and one's success is likely to improve with understanding of the differences.

[Bloomer001]

I agree with you Roberta, I'm learning that growing culture is the primary factor -- and is far more important than fert selection. I read your "101 culture notes" prior to potting these orchids. Your note re air circulation is 100% accurate. The orchid in the green pot is the smallest by far. The green pot orchid is in an internal plastic pot with holes, but the external green pot restricts air circulation compared to the open red tin that the other 3 orchids are planted in. I believe this factor caused the green pot orchid to grow about 30% less than the others in the red tin, with all other factors being roughly the same. When I repot next spring, I'm going to find a pot that allows more air circulation.

Coincidentally, the first flower is beginning to open today!