C. dowiana problem leave and spike

[Orchidcork]

Thanks so much, i as fertilizer i am using Peters, 20 20 20
, 10 52 10 , 10 30 20 , under 250 pmm. mostly in summer

But i bought pure calcium and boron, both independt, for plants , so do you think if i a am using this peters do i need still need add that?

By the way i feel was esced of humidity , without considering the temperature are going down, y also cutted the leave.

[rbarata]

Originally Posted by Orchidcork

Day temperature can reach in the day till 35, night above 20 , but yesterday was the first night got 18...

Those temps are not problematic...35 is more extreme than 18 but as long as the plant has a chance to cool down at night, it will be ok.

[Roberta]

Quiestion... you keep mentioning boron. This ie a trace mineral, should be in VERY low quantities, more can be phytotoxic. (Some may be more sensitive to overdose than others, but the need is very minimal for any) An orchid fertilizer will have the trace minerals that are needed, at the correct levels. Calclium is needed in much larger amounts - 75-100 ppm at each watering would probably be good. Either use s fertilizer that contains calcium and magnesium, or use a cal-mag supplement. Follow the directions on the label (or less) Orchids need very little fertilizer!

You also mention fertilizing on the leaves. This is useless for orchids - they have a cuticle on the leaves that protects them from dehydration but also makes what you put on the leaves just roll off. (It washes off the leaves and gets to the roots, but why not put it in the root zone to start with?)