Reading went ahead in the fourth minute when Sam Baldock pounced from close range following a corner from Leandro Bacuna.
Hull offered little going forward and conceded twice more in the last 20 minutes. Jon Dadi Bodvarsson tucked in his fifth goal of the campaign and defender Andy Yiadom added his first goal for the club.
Centre-back John O’Shea was sent off near the end for a last-man foul on Chris Martin, but Reading still eased to just their second victory of the season.
Adkins admitted: “We were very poor in the first half-hour in particular.
“We came here with a positive mindset, but we’ve conceded very early in the game from a corner. That gave Reading a big uplift. For that first half-hour we were second best all across the pitch.
“Reading won every first ball, second ball and we were a yard off everybody. Towards the end of the first half we got back into it and we started the game better in the first 20 minutes of the second half.
“We passed the ball better and we were probably in the ascendancy. But the second goal that we conceded, that was probably Reading’s first foray into our penalty area in the second half.
“We’ve got four or five players in there who should have tackled the player who scored. That’s then given the ascendancy back to Reading again. We’ve just got to go away and analyse it all. Then we’ve got to go again.”
Reading: Walker, Tiago Ilori, O’Shea, Moore, Yiadom, Bacuna, Ezatolahi (Swift 68), Kelly (Gunter 85), Sims, Bodvarsson, Baldock (Barrow 69). Unused substitutes: Aluko, Meite, McNulty, Jaakkola.
Hull City: Marshall, Lichaj, Elphick, Burke, Kingsley, Bowen (Grosicki 63), Henriksen, Stewart (Martin 63), Kane, Irvine, Campbell. Unused substitutes: De Wijs, Dicko, Toral, Long, McKenzie.
Referee: J Simpson (Lancashire).