The soil in raised beds can dry out quickly in the summer heat. Emptied two-liter bottles can be buried deeply, pierced with a needle or hat pin and filled with water to encourage plants to root more deeply. The slow release watering saves on water as well.
To prepare the bottles, pierce four holes towards the base of the bottle in a vertical line about one half inch apart. Turn the bottle a quarter turn and repeat the pattern of piercing. Repeat two more times to end up with four vertical lines of mini holes. Fill with water and screw on the bottle cap to slow the flow.
The needle can be heated in a candle flame to make piercing easier.