Have you seen a grass snake or a slow worm in your compost heap? Fear not, they are both completely harmless and both attracted to the warmth generated in the compost heap for their young. Grass Snakes are the UK’s only egg laying snake, they may lay a clutch of 10 – 40 white eggs: 2.5/3cm long.

Slow worms which are legless lizards, are ovoviviparous meaning that they incubate their eggs internally. The eggs hatch inside the female and she gives birth often to usually 6 - 12 live young.

   Grass Snake: Mark Hamblin (rspb-images.com)

  Slow Worm: Oliver Smart (rspb-images.com)

Both slow worm and grass snake young look just like miniature versions of the adults so you may discover these also, writhing about in the heap.

If you want to turn your compost heap, try to leave it until October or turn it carefully with your hands wearing thick gloves… this is more to keep your hands clean and protected from rose thorns rather than a snake bite. If a grass snake is cornered, it may inflate it’s body and hiss loudly in defence, even dart forward with a warning strike, with its mouth closed. They rarely bite. There are some fascinating images online of grass snakes playing dead, lying sideways with their mouths open; another of their defence mechanisms against predators such as badgers, birds of prey, cats and foxes.

Slow worms can shed their tail to escape from predators which also include adders and hedgehogs. Even when that part of the tail has detached, it can still wriggle as a distraction to allow the slow worm a better chance of escape! ... and a new shorter tail can regrow.

 At Flatford, we currently have Grass Snake eggs in the compost; they are discovered there every year and adults can often be seen nearby basking in the sun. Slow worms prefer to stay hidden so do not “bask”, they will only be seen out and about traveling through vegetation on their way to somewhere.

Grass Snakes and Slow Worms will be looking for a place to hibernate in October, maybe underground, in wood or leaf piles or perhaps they’ll be stating in the shelter of the compost heap so always be aware when turning the compost.

Being early September, there's still time for the thrill of a sighting of either of these protected garden reptiles.

Here are some suggestions on how to attract reptiles to your garden and the RSPB have books with more information in their online shop on snakes and garden wildlife in general.


The Flatford Wildlife Garden currently remains closed but re-opening details will be posted in advance on this blog and the main Flatford webpage. The Flatford team continue to encourage wildlife through their own gardening projects and very much look forward to sharing wildlife gardening experiences with you when we re-open.

Anonymous