We love fresh, small courgettes and have five plants from seed this year, two in the greenhouse and three in large pots outside.  I feed them when I remember!

Because we had a lot of female flowers that weren't getting fertilised, I've been darting about with a camel hair brush each morning transferring pollen from male to female (pref on a different plant).  But many of those I've fertilised have a very thin top half and a normally developed lower half - ie, only the lower half of the fruit is developing.  Anyone know what I'm doing wrong?  (the naturally fertilised ones are fine and tasty, BTW).