Q. we live in a house backed onto the beach, the garden has sandy soil, is this ideal for growing vegetables?
A. If your beach is ocean you may have a problem with salinity! Ocean water, or even occasional spray landing on your garden soil will likely leave salt deposits that make it difficult or impossible for vegetable plants to grow.
If you have ample clean water you should water the garden very heavily three times before planting. This should flush out the excess salt enough to let you grow a healthy crop.