Seasons stretch to fill the shelves

There is a body of opinion that believes that shops should respect the home-grown season for produce such as asparagus and strawberries by not stocking them out of season. While it is an understandable sentiment, it is not realistic. Year-round availability is here to stay.

And this is where horticulture can play a positive role. If the choice is between a new variety of vegetable developed to be grown at home out of season, and some highly durable variety grown in Latin America or Africa where controls are not as stringent as they are in Britain, at that point I am in favour of extending the home-grown season.

In fact the seasons are changing so fast year on year with the development of new varieties and new farming methods that it is difficult to say with any confidence exactly when they fall for any given fruit or vegetable. It has become accepted that there is an early, a mid and a late season for most crops, and more recently I have heard the term "extra-late".

The point at which extending the seasons becomes distasteful is when there is a reliance on unnatural methods of production, artificial daylight, or chemicals. There is nothing wrong with glasshouse production; we have been practising it for hundreds of years. It is the extremes that are questionable.

Likewise we have been cross-breeding crops to produce certain features for a long time, and there is no reason why a new variety should not be as good as, or even better than, an existing one. It is when the breeding is purely for yield or speed of production and there is no consideration of quality that it becomes negative.

The real danger lies with transgenic varieties, those that have been created by moving DNA from one organism to another. It is difficult to see anything good about tampering with nature in this fashion. But to see all new strains in a negative light simply because they will supersede old varieties or change the status quo is to deny the existence of progress.