When you fill up your strimmer with strimmer line, do you ever think about all the tiny little bits of plastic that you have spread all over your allotment?
With people becoming more aware of the problems with microplastics in the environment, perhaps it's time to consider using bio-degradable strimmer line.
It's available on Ebay. It's a little bit more expensive than plastic strimmer line and it evidently runs out a bit quicker too, but at least you wont be showering your plot with tiny pieces of non biodegradable plastic.