Question
Mike, I live in the Richmond, VA area.  I have a raised garden bed. I want to put 1.5 liter plastic bottles buried towards the roots of my tomato plants, how much should I water them per day?  I was told to fill each bottle with 1.5 liters per day. Is this correct?  I want to use the bottles so my young daughter can "help" me out there, this is why I am choosing to use this manner of watering, any helpful tips would be appreciated  

Answer
Anthony, tomatoes should receive 2" water per week. I know gardeners who use the method you are describing. The primary advantage, as you stated, is that the water never touches the foliage but rather goes directly to the roots. The water is dispensed very slowly and only is drawn in as needed based on the moisture level of the soil.

This works well for gardens with only a few plants. I personally use soaker hoses that are snaked through my raised beds and covered with straw or dried leaves. The water is dispensed through hundreds of tiny holes and only wets the soil. I turn them on for 30 minutes three times per week. The advantage is that the hoses water the entire garden rather than just a few plants.

Either method is recommended because anytime you can irrigate the garden without overhead watering is beneficial since you avoid fungus and other diseases that can be caused by wet foliage.

I hope this answered your question. Please write again if I can ever be of assistance.

Regards,

Mike