It is a funny idea. A few points:
1. First, don't open your door for the police - period. The police only ASK to search your place when they don't have permission to kick down your door.
Just say no. Don't answer the door at all -- fuck 'em. Just stay inside, they will go away eventually or they will break down your door. Either way you have no reason to get off the couch. Only by opening the door and talking to them can you give them evidence that would be useful in securing a search warrant. You have no obligation to talk to them under any circumstance. Treat them just like any other asshole that bangs on your door trying to sell you magazines.
2. The police think everyone is guilty of something. They are unusually paranoid and they deal with bullshiters every day. They are trained to pretend to be your friend to develop a rapport, then when you are getting buddy buddy with the nice police officer he will turn on you and use the "trust" you two have been developing to manipulate you into giving up your rights. Do not engage in small talk with law enforcement.
3. Exercising your 4th amendment rights under the Constitution can never be held against you whether it comes to getting a warrant or as evidence of guilt at trial.
The prosecutor cannot comment on it to the jury. It cannot be held against you.
4. If you find yourself in the unfortunate situation where the police are at your door asking to search your place,
Just say no. Whether the cops think your ass is hiding something or not is irrelevant. A hunch is not enough to get a search warrant, but an anonymous tip may very well be. If anything, if the police already know you have the equipment and capability to grow vegetables hydroponically then that is the kind of evidence that would be relevant in securing a search warrant.
5. At the very least, the police will break down your door, trash your house, steal your equipment, and cart you off to jail. If and when you get your equipment back it will be broken and unusable. How many botanists do you think they have on staff at the local PD? They are going to assume you are growing something illegal and jail your ass. You will have to hire a lawyer and spend $5000 just to get the police to realize they've arrested some weirdo with a vegetable fetish.
But it's a fun idea.