I don't really understand what you're asking. Do you just want the LED to come on when it's dark and go off when it's light, or does the light coming out out the LED have to be sensed by the LDR and the circuit react to it? Can you please clarify or post a schematic?
Are you just connecting the LDR in series with the LED? If yes, then because the LDR's resistance decreases with increasing illumination, then the LED will turn on when light falls on the LDR. It would take the addition of a transistor and some other components to "invert" the function.
To do a detailed design, I would need to know the resistance curve of the LDR. This shows the idea, but the actual resistor values would depend on your LDR, Battery voltage, and LED. The plot shows LED current vs LDR resistance.
The LED doesn't care what the supply voltage is as long as it has the correct current-limiting resistor in series with it. Look at R1 in my circuit. It limits the current to 18mA.
Here is a modified circuit that starts with a supply voltage of 5V. I still need to know the resistance of the LDR when it is in dim light.
D1 is the Light Emitting Diode (Red is modeled). The plot shows current through the LED (Y axis), which controls its brightness, as a function of LDR resistance (X axis).
The current to rise, the resistance goes up, the farm business! then this circuit is for what I precizē? just make these connections, and connect the LED on the site of the D1 component in the circuit?