Help with lua coding

I’m trying to make a watermelon bomb that works just like a frag grenade but I’m having trouble coding the explosion. Here is what I have (for the primary attack part):

function SWEP:PrimaryAttack()
	//Call the throw attack function, with the watermelon model

	local entpos = ent.GetPos();
	local explode = ents.Create("env_explosion")
	explode:SetKeyValue("iMagnitude", "220")
	explode:Fire("Explode", 0, 0)
	explode:EmitSound("BaseGrenade.Explode", 400, 400)
	timer.Create("timer1", 2.5, 1, ents.Create("env_explosion"))

I have a feeling that my problem has to do with finding the physics prop (watermelon) to create the explosion there.

[editline]24th July 2015[/editline]

oh wait nevermind.
I realized I posted this in the wrong place.