I am priveleged to be working on 2 new sensory gardens for special needs schools at opposite ends of the UK. The techniques used in a school apply equally to any sensory garden.
It is important to introduce life into the garden.
Water is essential. The sound of trickling water is torture for some people but others love it. Choose a water feature to suit your needs, and those of the local wildlife. If you are placing a free standing pond in a barrel, or similar, make sure that frogs can get in and out of the water with a ramp access of some sort.
Sunlight is also essential for life, so a sunny corner seat is a great way to enjoy the experience of letting the sun warm your bones.
A great way to add life to a garden is to add to the biodiversity of the area and plant a selection of trees, shurbs, flowers and grasses. If you leave logs and damp stones, moss and lichens will colonise the area as well. By introducing a wider range of planting you will encourage a wider range of invertebrates and vertebrates into your garden. Birds, frogs, butterflies and all manner of beneficial insects will naturally balance the unwanted bugs in your garden.
Sound and light are important sensory stimuli. Whether you use splashing water or wind chimes, bird song or hollow log drums set aside an area of the garden to be a little noisy. Light affects the way we see colour. For people with vision impariments it is important to have areas of light and shade, as well as brightly coloured planting and furniture within the garden. Create shady tunnels with bean, grape or espaliered fruit tree pole pergolas over a path so you can pick and eat as you walk through.
An edible sensory garden stimulates our sense of taste. Young children put everything in their mouths to fully make 'sense' of the unknown. As we learn to identify objects we make less use of our taste senses. We can stimulate them with delicious fruits, nuts, vegetables, herbs and edible flowers, planted within easy reach of the path.
