WHAT TO DO
ADRIAN THOMAS RSPB wildlife gardening expert It’s great to consider creating green roofs on sheds and garages. If the roof can hold the weight of the soil, water, plants and maybe snow on top, and if it has a slope of under 20 degrees (but not flat), it will need waterproofing that will also be root proof (such as EDPM pond liner). You’ll need raised edging to hold in the 7-15cm of substrate, a mix 75% crushed rubble to 25% compost. Make sure excess water can drain away. Then plant! You’ll do best if your roof is in a sunny position. Sedum mats are fine, and don’t need as much substrate. But chalk downland mixes, including plants like Lady’s Bedstraw, also work and provide more variety.