since then, you've needed planning permission to do that for an area of five square metres. gardens max your physical, mental, and social well—being. with the covid—19 impact, i think people are recognising the health benefits. the royal horticultural society's garden in wisley. it's notjust home to thousands of beautiful plants — a lot of research goes on here. there's a new science centre being built. we've just recently done a study where we put two tiny planters and a tree in a salford street, and we measured cortisol, which is a stress hormone. we found a 6% decrease in stress, which is equivalent to eight mindfulness sessions. and for anyone without a front garden, the team here believe a window box or a pot can also make a big difference, helping pollinators such as bees, or even reducing pollution. just some silver—leafed plants will really help.