Walls to kitchen garden, including gardener's cottage, at Mostyn Hall

The walls surrounding the kitchen garden at Mostyn Hall are large and rectangular, constructed from red brick with flat stone copings. There are doorways with segmental brick heads and boarded doors on the east and north sides, and a wider entrance on the south side. The walls are double-skinned with cavities to enhance heat retention. Although the garden is currently unused, it is divided into quadrants by former paths, with some surviving black kerbing tiles. At the center, there is a circular water storage pool that used to have a fountain.

To the north, there are two smaller enclosed gardens of unequal size, accessible through a doorway. The left garden features full-width lean-to glass houses along the north wall, built on a red brick plinth, with opening lights that have large panes. The roof is supported by wooden vertical struts and glazing bars with overlapping panes. There is an offset doorway leading to a through-passage that connects to the exterior north wall of the gardens. This wall supports a long range of buildings made from red brick, which includes bothies, a potting shed, and a boiler house, all topped with a corrugated asbestos roof and a truncated lateral brick stack. The openings in this range are segmental-headed with boarded doors, and most windows are 2-light wooden casements, along with skylights.

Adjacent to the east end of this range is a gardener's cottage, which is symmetrical, two stories high, and has three windows. The cottage is whitened and features tall brick lateral end stacks. The lower storey has openings with segmental brick heads, including a central panelled door with a three-pane overlight under a canopy, flanked by a 2-light small-pane casement on the left and a 3-over-6-pane hornless sash on the right. The upper storey has three similar sashes with flat lintels. To the right of the cottage, there is an extension, likely originally part of the bothy, which has late 20th-century windows. This extension features a pair of tall round arches on the ground floor, an infilled doorway to the right, and a window inserted beneath to the left, with an additional window on the upper storey. The east gable end has a 2-light casement window offset to the right. At the rear, there is a private garden, which is the second of the small enclosed gardens.