what to use for the top layer in pots

can anyone please tell me what can be used as the top layer in pots to stop the top 10mm of soil from drying out under lamps.
can you use gravel (washed) or is there a certain type of media thats used.
cheers
moxx

peat moss....

Wow. the top 4" is getting too dry. How deep are the pots? Since water will flow down (that little gravity thing) you would have to mix a moisture retaining medium, or maybe get you temps under control. VV

You did mix the soil with some perlite or verm right? How close is the light that its drying 4 inches of soil without burning your plant? Light size and type?Humidity in the grow area?

VictorVIcious said:

Wow. the top 4" is getting too dry. How deep are the pots? Since water will flow down (that little gravity thing) you would have to mix a moisture retaining medium, or maybe get you temps under control. VV

Click to expand...

10mm = 1cm

10cm = 4"

its 10mm (millimeters) or around half an inch .
i have mixed retaining media with the soil and the lights are about 12" (inches) away from the top of the plants.
its just the top serface thats getting a little dry, i just need a top layer of gravel or similar to help.
any ideas please.
moxx

temp in the grow box is a steady 78-80 degrees and light is a 400watt HPS