Picture posting is enabled for all :)
Maybe raise it up a bit, as they say the carrot fly doesn't go above 2ft (no doubt someone will say this is not true!). I use metal dustbins for mine, so a bit more depth.
It has become my view that, in general, allotmenteers tend to be too conservative, slavishly following convention and not thinking of what they actually are aiming to produce. When I read of constant concerns about the appearance, the time spent (wasted!) in tittivating,(and rotovating!) rather than maximising the successful production of quality, tasty vegetables and fruit, and the provision of all the basic conditions of fertile ground.
The thermal currents are obviously the answer
"pea tubers" ?would that be Lathyrus tuberosus ?