I had the same problem with my 5 feets Needle palm. I used C9 with T3 in the mummywrap method. When i toke off the protection, it had all the outside fronds dried, but the Inside fronds was green. After 2-3 weeks, it became to dried completely, i don't know why. Never the temp. Inside the protection was over +15c. But i think the C9 was to hot for the leaves and shock the palm

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Mike used a 23 watts CFL with T3 and his Needle was better than mine this spring. Maybe its the way to do. With avoiding the leaves to touch directly the heat source like C9 or CFL bulb.
Ben