I've recently been convinced that my potting soil which contains a lot of homemade compost (made primarily from leaves and fruit waste as the greens) is generally lacking fertiliser. My strawberries, amongst other things, have become leggy.
The only reasons I can find as a cause of tall spindly plants are excess nitrogen and lack of sunlight. Neither of these seem to apply. They have full access to sun from dawn to 2.45pm then are in the shade of some trees for the rest of the day.
So my question is - Is there anything else besides lack of sunlight or excess nitrogen that could cause a plant to become leggy?