To think this isn't safe?

[outofthisplanet]

So neighbours have a green house. It backs onto our garden fence. There’s a few cracked panes of glass and it’s seen better days.
For the past week they appear to be lighting around 10 candles in there and leaving them burning all night.
I’ve googled as I couldn’t work out why they were doing it, and I think it’s to heat up the greenhouse.
I’m just a bit concerned that a gust of wind will blow in from a cracked pane and knock a candle over causing a fire next to our fence.
Not sure what’s massively flammable in there.
I suppose they use those cardboard seedling pots and there’s bags of compost etc.
Could this cause a fire or am I being ridiculous?!

It's been raining for weeks. Any idea how hard it would be to burn a fence down currently? It's much more likely to blow over in the wind, and you won't be able to get compensated by the neighbours for that one.