The use of peat, primarily as a potting compost, has damaged or destroyed 94% of the the UK’s peat bogs. Kew took the decision to stop using peat in 1989, except for carnivorous plants that cannot be grown in any other medium. It now uses peat substitute for potting and makes home-grown compost and mulches at Kew and Wakehurst using waste plant matter from the Gardens.
On the eastern boundary of Wakehurst, close to the Iris Dell, is Compost Corner. This is where waste material from the estate is piled into heaps, mixed with manure and left to rot down. Wakehurst also has a partnership with Ashdown Forest to compost bracken. The forest workers gather up bracken waste each year, to help regenerate heather plants there, and bring it to the estate. When rotted down in Compost Corner this provides a ready supply of acidic compost useful for mulching acid-loving rhododendrons and improving the soil across the estate.
Compost Corner allows visitors to look into the compost heap complex, with its turning and sorting machinery. The piles of prunings and dead leaves are set out in rows and turned regularly throughout summer to help them decompose. They are left to mature through the autumn months. Stacks can be seen in varying stages of decomposition, from weeds and raw clippings to rich dark mulch. Wooden boxes at the entrance of Compost Corner contain envelopes and sandwich wrappers, which also rot down over time.