A sun lamp as in a heat lamp? If so, NO, NO, NO! What size pots are you using? Going away for 3 days should not have drained the pot of moisture, I water mine every 3 days and it's rare that the soil is fully dry after the 3rd day and good for the plants if it is. You don't want soil-grown plants constantly wet anyway. My guess is, if you watered heavily before leaving then came back and gave them another good dose of water so they're waterlogged and need a break for several days to dry out. But then again if you're using a sun/heat lamp they could be baking. We need more info to be of any real help or else we'll just be pulling answers out of our butts and you'll have dead plants, before their time. What size pots? What kind and wattage are your lights? How often do you fert and what brand and dosage?

But whatever you do I'm sure it doesn't need more water, as in flushing. You ONLY flush when too much of an additive gets into the soil and for no other reason. Too much water is always worse than not enough and much harder to fix the damage.