I’ve started gardening on my balcony recently, and came across the ‘air-pot’ system. Air pots are a kind of planter with an egg-box-like surface and lots of holes. Normally in a potted plant, when a root hits the side of the pot it is deflected and roots start to grow in a spiral round the pot. Over time, these roots grow into a dense mat which does not absorb water and nutrients very well, and may be prone to rotting and disease. The design of the airpot directs roots, when they reach the edge of the pot, to poke through the holes, where of course they dry out and are ‘pruned’ by the air. This encourages new roots to grow from the base of the plant, so instead of a thick unhealthy coil of roots at the bottom of the pot you end up with a mesh of new healthy roots spreading throughout the soil. Unfortunately the air-pots are rather expensive.

It occurred to me that crocheted plastic bags would have a similar effect – the rounded bumps of the stitches would encourage root tips to grow through the holes between the stitches, while the holes would give really good drainage and the layers of plastic would insulate the roots from extremes of hot and cold. So I give you, the crocheted plarn planter!

A 5in pot takes about 10-12 plastic grocery bags to make.

I’ve got a whole lot of lettuce seedlings doing nicely in mine :D