Bricks and mortar

Part of the garden wall was threatening to fall down, so we are having it re-built. Most of the bricks that were whole in the old wall can be re-used, and the new wall is being done with lime mortar, like the original, i.e. no cement at all. And thus was most of Camberwell built.

This isn't just conservation fussiness - lime mortar has a hugely lower carbon footprint than does cement. It also has the indirect effect that when you take a wall down you can get the mortar off the bricks. The only bricks we couldn't re-use here were the ones that had been repaired with cement. When you lay bricks with cement you doom them to single use.

So reclaimed London stocks are only available because of the lime mortar they were put together with.

Great tree

This wonderful tree, which I take to be a black locust, Robinia pseudoacacia, looks as though it belongs in a park or large garden rather than where it is, on the pavement in Wyndham Road. Certainly the tree is much older than all the surrounding buildings and, in its solitary splendour, it doesn't look as though it was designed for the pavement. Perhaps a large garden is where it used in fact to be, and Edwardian children played under it; but the garden has long since been taken away. How good that it has survived.

Biodegradability

What does it mean to say something is biodegradable? Our answer is that if an object is still identifiable after a year in a fairly cool compost bin, it is not biodegradable in any useful sense.

But it is difficult to carry out a comparative trial in a compost bin, so we are trying a substitute approach, putting stuff on the soil surface, covering it with a black plastic bag, and keeping it moist. On 4 July we started with an Ecover bag (A); an M&S potato carton (B and C); a Kanga incontinence pad (D); and an Earthfriendly eco baby wipe (E). More recently we've added a Weenee nappy pad. All the products claim 100% bidegradability/compostability.

The pads seem to be entirely wood-based pulp and tissue, except that the Weenee admits to having some gel ("superabsorbent polymer" - crosslinked polyacrylate). The other items all seem to be made of a polymer derived from starch, poly(lactic acid), or PLA (trade name Ingeo).

So we'll have a look at how they are getting on every couple of months.

Butterflies

We are seeing Holly Blues in the garden. The Holly Blue is a gift to non-butterfly experts like us - it is the only small blue butterfly that you normally get in Camberwell. So if you see a small blue butterfly you can say knowledgeably that it is a Holly Blue. According to the RSPB, "Adults drink oozing sap, aphid honeydew and carrion juices", not so charming, and "Caterpillars usually eat holly and ivy, but also dogwood, spindle and heathers." Ours are often flying round the ivy - perhaps ready to lay eggs.