The Forest boss was disappointed at his side's second-half display in Saturday's 2-1 defeat at Swindon that left the Reds with just three points from the opening week of the season.
He told the club website: "In all three games so far we have been on top in the first half, but even when we are on top we are still not scoring enough goals.
"Our forwards are not getting enough efforts on goal, in this game we had eleven corners and got nothing. Swindon had two and scored from one of them."