Nepaljam x Oaxaca
Active Member
As I learn more about orchids and their nutritional needs, it becomes apparent that there are two primary factors to be considered: availability of a range of nutrients, from the macro- to the micro- and trace elements (see this for more info), and the amount of nitrogen that is supplied. If you use a decent, complete fertilizer, the first criterion is satisfied, so you only have to focus on the nitrogen loading.
Studies at Texas A&M have shown that for phalaenopsis growing under their green house conditions in bark-based media, nutrient solutions providing about 225 to 250 ppm N is optimal for growth and flowering. Considering the lower light flux and average temperatures in my greenhouse in michigan, plus the varied collection I have - from "heavy feeding" vandas to phrags that don't like a lot of dissolved solids in their irrigation water - I shoot for aconsiderably lower target, more in the range of 100- to 150 ppm nitrogen.
Studies at Texas A&M have shown that for phalaenopsis growing under their green house conditions in bark-based media, nutrient solutions providing about 225 to 250 ppm N is optimal for growth and flowering. Considering the lower light flux and average temperatures in my greenhouse in michigan, plus the varied collection I have - from "heavy feeding" vandas to phrags that don't like a lot of dissolved solids in their irrigation water - I shoot for aconsiderably lower target, more in the range of 100- to 150 ppm nitrogen.