flush with bottled water that should have close to 7pH if you dont have a pH tester I suggest going to your local fish or hydroponic store and getting a soil pH tester. They run about $8-$10 for the test strip type. pH for soil should be anywhere between 6.5-7.5 I believe.

Once you flush your plant all the way out you need to let it dry for a few days or more. A good way to test is to put your finger in the top soil and it should be dry to about 3 cm below the surface. If it is still damp do not water. Overwatering is the number one stressor new growers commit but the trick is to get a good idea of how much your individual plant needs. There are many guides out there but look at your plant often and determine what it needs and what it doesn't.

what kind of soil are you using? how aereated is it? Hopefully that is the dull side of the tin foil other wise it will cause hot spots on the plant from the light.