Does Samhain, 2015 affect your fourth house in Astrology? No clue.
I'm a Numerologist and this year's combination of double 4 vibrations for October 31st emulates that of the 4th house. It centers around the home, and with emphasis upon security and stability.
Samhain generally has us looking at our ancestry, and family roots, as the veil between the worlds wanes thin. Ancestry and family roots (also found within the 4th house) is magnified by the double 4s with its focus upon our foundations.
This year, what will the emphasis of your Samhain or Halloween ritual be? According to Numerology, centering it upon the home, security (financial or otherwise), studies (something you enjoy or genealogy), stability (of home and family) would be most appropriate.
The color brown, used in house blessings, animal/pet magick, earth magick, concentration, material goods, stability, earth element, real estate, and financial crisis,
The color green, used in prosperity, abundance, money, tree/plant magick.
And above all, incorporate the magick of intent, for what you think, you create. Your words are your magick - choose them wisely.