new lemon fruit turning black?!

Help please...
My lemon tree is doing the same thing as las year. Stacks of little baby fruits are appearing, but they are all turning dark / black, and will fall off soon. What is wrong with the tree, any guesses?

last year from about 30 fruitettes (sp) I got one lemon - it was a good one, but sadly only one.

any help - ideas much appreciated.
Ta
Scribe

 

Lots of questions to ask. Whereabouts are you for starters, Britain or abroad? Is the lemon inside or outside? Is it in the ground or in a container? What type of soil/compost is it in? How have you been feeding it? Have you been spraying it with anything? Is it in dry or humid conditions? That`ll do for starters. lol lol lol Welcome to the site by the way.lol lol

 

oh hi Daithplant
Phew, lets answer that lot. I'm in the UK, East Midlands. 2yr old tree in a large pot, that lives outdoors all year but comes into the conservatory for winter. Compost - heck just normal stuff nothing special afraid, and guess that is 2yrs old now. I did feed all summer with nettle juice and a little handful slow release pot fertilizer. Spray? Nope - just the odd watering to wash the dust off the leaves.