help someone?!

whats up everybody.. i was just lookin for some help with my plants...
i got 6 of them growing outdoors and they are lookin mighty fine! but one of them, the leaves are turning purple and at first i got excited. i go back in a week i see yellow spot on the purple leaves. a couple days later i pulled of a dried up nugget from one of the branches and i dont know what it can be?!?!
does anyone have an answer for my problem?

5 out of six aint bad....it beez thata way

iz it cold out maybe ???

yeah i guess thats right but this one has the most buds on it..

turn purple. I grew indoors, and the plants that got cold turned purple on the leaves. It didn't harm the growth (working under controlled conditions helped) at all, but I panicked at first, try to keep 'em warmer to ensure proper growth and budding.