Can this be cast at higher levels?

In my games, I say yes but it just doesn't receive any mechanical boost to it.

If a friendly NPC uses their action tries to break the entanglement, is that aloud?

A creature restrained by the plants can use its action to make a Strength check against your spell save DC. On a success, it frees itself.

No, the attempt to break the entanglement can only be performed by the restrained creature to free itself. Obviously, [insert boilerplate text about DM interpretation and situational stuff], but RAW, no.

Will this clog machines

Quote from DacEnDale >>

Will this clog machines

Completely up to the DM, to be honest. It's not listed in the spell but, provided that the machine has sufficient "ground" in contact with machinery, I'd certainly allow it.

However, don't expect that to work in a rules-lawyery game. It's not an explicit use of the spell, just an intuitive result of it conjuring "Grasping weeds and vines".

So, I did notice that your illustration implies that the spell operates in a 20 ft cube. That's not correct, if it were a cube it would say so and the image above would be a three dimensional object instead of a flat square. It's a 20 foot square set along the ground, and there's really no text that implies it could ensnare things flying in the area above where the grasping plants form.

Say one player cast Entangle on a creature, then another player casts Fireball on said creature, would the "Grasping weeds and vines" be burned away, allowing the creature to no longer be restrained? Or would it have to be specified that the plants can be burned away like in the Web spell?

As a DM I would say they would burn when the fireball hits. Sprouts normal plants in the area its not a magical plant so its just ordinary plants that can burn and take damage just like the entangled creature or object.

20 ft. “radius” square, that’s a lot of space.  16 spaces on a tactical map.

Pretty good for a first level spell, might even be worth keeping concentration on.

Does the arena have to be visible? The spell doesn’t define that the a creature has to be visible. A player cast this spell into a spot in warehouse that was not at all visible from her position. Only information the player knew was her party members were attack two enemies at the door way.  Yet she casted it into middle of the warehouse to entangled all the enemies but just outside range of her party members. Argued that she shouldn’t  be able to count squares into warehouse to do this since from her position she could see the third enemy. I guess in hindsight I could have covered the map. Is there a rule for this ? This was my first time DMing.  

Quote from Rigwaltz >>

Does the arena have to be visible? The spell doesn’t define that the a creature has to be visible. A player cast this spell into a spot in warehouse that was not at all visible from her position. Only information the player knew was her party members were attack two enemies at the door way.  Yet she casted it into middle of the warehouse to entangled all the enemies but just outside range of her party members. Argued that she shouldn’t  be able to count squares into warehouse to do this since from her position she could see the third enemy. I guess in hindsight I could have covered the map. Is there a rule for this ? This was my first time DMing.  

Technical answer:  you don’t need sight (so you can still cast when blinded), but you still need lime-of-effect (you can’t just cast through a solid wall).

Practical Advice:  don’t be afraid your foot down and say “no” as the GM, if you think something is wrong.  However, if you find yourself hesitating to make a ruling, just ask the player to roll something (in this case, a difficult Wisdom check would probably be appropriate).

The big thing is to not get caught up in detailed arguments, those can eat up a lot of time.

It doesn’t say radius, just square, just like web and grease. Squares don’t have radii. 

Quote from ColdLogic >>

It doesn’t say radius, just square, just like web and grease. Squares don’t have radii. 

Funnily enough, the Basic Rules/PHB doesn’t cover square Areas of Effect.

I suppose they may be calculated along the side, like a cube, with the point of effect on one side.  I just naturally assumed it extended from the center.

You know, the more I think about it, I agree with you. I must have been caught up in semantics that day.

I only play on roll20, so to me 20ft square is 16 boxes like you said. 

Quote from ColdLogic >>

You know, the more I think about it, I agree with you. I must have been caught up in semantics that day.

I only play on roll20, so to me 20ft square is 16 boxes like you said. 

All good man.

Yah, I find talking in squares is often easier for these things (though it doesn’t sound as cool on paper).

Casting word is:

Halicium Entanglarium

Cool.

Okay first time Dm... If a creature frees its self but doesn't leave the area will it get entangling again? Also if the creature breaks free and leaves the area do the vines stay for the whole minute?

Thanks

The entangle effect only happens when the spell is cast, and only to creatures that are within the area at the time.

The vines will stay for the full duration and make the area of the spell count as "Difficult Terrain," meaning that it takes twice as much movement as normal to cross the 20ft square (so it takes 40ft of movement to move across the whole square).