You can help avoid plants drying out by erecting netting to give some shade and break the force of the drying wind. This is very useful for plants which don't like hot conditions, like lettuce for instance. The support doesn't need to be anything fancy as you aren't trying to completely enclose the plants, just give them some shade during the hottest part of the day and soften the effect of the wind.
For more tips on helping plants to cope with Kent's dry summers, click on Using Water Wisely to go to our advice section.