Ghost gardens and air raid shelters: the archaeology of a heat wave

Ghost gardens at Gawthorpe Hall 📷Lancashire Council

Britain has been basking in glorious sunshine for weeks and as a result, something extraordinary has been happening on ground level.

Whether you love or hate the heat, the warm weather we’ve been enjoying here in the UK has been wonderful for archaeologists, particularly in Wales, Scotland and Ireland. With Britain currently experiencing its longest heat wave since 1976, and the hottest June ever recorded, an extraordinary number of crop marks have appeared, many with astonishing detail.

Air raid shelters are showing up in Cambridge 📷 SWNS.com via The Independent

Crop marks show up in hot weather because of differences in the soil beneath ground level. For example, ditches that cannot now be seen above ground often retain moisture and nutrients better than surrounding soil, therefore, during long summers, the crops planted over a ditch will look much greener and more luscious than nearby vegetation.

In contrast, areas with underlying stone structures will often cause the above vegetation to die more quickly as the soil heats up faster.

From air raid shelters of the Second World War, to 19^th century ghost gardens and barrows of the Bronze Age, many of these crop marks have never been seen before – and archaeologists are scrambling to get aerial photographs to record the new sites.

Anthony Murphy discovered a never before seen henge in County Meath 📷 BBC News

Ms Barker of the Royal Commission on the Ancient and Historical Monuments of Wales said “The heat has allowed us to do things over a huge area that no amount of digging or ground radar surveys could have achieved, unless you had an unlimited budget and were willing to go slightly mad prospecting in hundreds of farmers’ fields on a hunch”.

It’s now a race against time for archaeologists to get the sites recorded before the rain comes and causes the crop marks to disappear.