Deposits for allotment

An allotment is not the only thing one can "invest" in where one might have to pay a deposit. I paid a £60 deposit, subject to similar conditions and THAT is nothing really, given the cost of other hobbies (especially when spread out over years when, in all likelihood, you would get it back if you leave if you are a decent "tenant".

I personally think the deposit is totally reasonable. even if it is in a poor state to begin with.

ie) what is to say you (I am sure you yourself, won't, but a theoretical "you") turns the plot in an even worse state, full of broken glass, other debris and vile stuff (and there are plenty of plots like that) and decide to leave. In theory it will be the deposit you had paid that should go to pay for clearance of it. In theory!!  In practice I know that many sites don't actually use that money towards cleaning it up (that falls on new plot owner's shoulders which I always find a bit of a cop-out on those who run the sites) but paying a deposit and with the "threat" of not getting it back might make a decent plot owner ensure their plot does not get it into an appalling state.

Or more to the point, it is a good punishment for the wretch who does leave it in a bad state and does not get money back.

Then again, if someone new to a site balks at paying a deposit (and I know you don't) there will be plenty of others on the waiting list who would not think twice about it.