
309 S.E.2d 488 (1983)
STATE of North Carolina
v.
Johnny B. GOFORTH, Howard B. Rosokoff and Virginia Lee Reynolds.
No. 8328SC121.
Court of Appeals of North Carolina.
December 6, 1983.
*491 Atty. Gen. Rufus L. Edmisten by Associate Atty. Gen. John R. Corne, Raleigh, for the State.
Herbert L. Hyde and Max O. Cogburn, Sr., Asheville, for defendants-appellants Johnny B. Goforth and Howard B. Rosokoff.
Robert L. Harrell, Asst. Public Defender, Asheville, for defendant-appellant Virginia Lee Reynolds.
EAGLES, Judge.

I.
Defendants assign as error the trial court's denial of their motion for appropriate relief, after the return of the jury verdict, on the grounds that the conspiracy indictments do not charge any violation of the law. For a valid indictment, there must be such certainty in the statement of accusation as will (1) identify the offense with which the accused is sought to be charged; (2) protect the accused from being twice put in jeopardy for the same offense; (3) enable the accused to prepare for trial; and (4) enable the court, on conviction or plea of nolo contendere or guilty, to pronounce sentence. State v. Sparrow, 276 N.C. 499, 510, 173 S.E.2d 897, 904 (1970), cert. denied, 403 U.S. 940, 91 S.Ct. 2258, 29 L.Ed.2d 719 (1971). We find that there was uncertainty as to the offense charged sufficient to render the indictments here invalid and hold that defendants' motion for appropriate relief should have been granted.
The indictments recited that defendants "did feloniously conspire . . . to commit the felony of trafficking in at least 50 pounds of Marijuana G.S. 90-95(h). . . . This act was in violation on [sic] the following law: 90-95(h)(i)." Because the offense charged was a conspiracy, the citation to G.S. 90-95(h)(i) should properly read "90-95(i)." G.S. 90-95(i) establishes the penalty for conspiracy to traffic in marijuana as the same as for trafficking in marijuana as provided in G.S. 90-95(h). Trafficking in marijuana consists of either selling, manufacturing, delivering, transporting, or possessing "in excess of 50 pounds (avoirdupois) of marijuana." G.S. 90-95(h)(1). Thus, an indictment for violation of G.S. 90-95(i) must charge a defendant with conspiring to traffic, sell, manufacture, deliver, transport, or possess in excess of 50 pounds of marijuana. See, State v. Anderson, 57 N.C.App. 602, 292 S.E.2d 163, cert. denied, 306 N.C. 559, 294 S.E.2d 372 (1982).
These indictments are invalid because they charge that defendants conspired to traffic "in at least 50 pounds of *492 marijuana." An indictment must particularize the essential elements of the specified offense. State v. Sturdivant, 304 N.C. 293, 309, 283 S.E.2d 719, 730 (1981). Weight of the marijuana is an essential element of trafficking in marijuana under G.S. 90-95(h). State v. Anderson, 57 N.C.App. at 608, 292 S.E.2d at 167. Conspiracy to traffic in marijuana is not alleged by these indictments because "in at least 50 pounds" is not "in excess of 50 pounds." Because of the fatal error in failing to allege all the necessary elements of the offense, the indictments here were invalid.
Judgment must be arrested when the indictment fails to charge an essential element of the offense. State v. McGaha, 306 N.C. 699, 295 S.E.2d 449 (1982); State v. Cannady and State v. Hinnant, 18 N.C.App. 213, 196 S.E.2d 617 (1973). Therefore, defendants' motions for appropriate relief were improperly denied, and judgments in these cases must be arrested. See G.S. 15A-1411(c).
The legal effect of arresting judgment is to vacate the verdict and sentence. The State may proceed against the defendants if it so desires, upon new and sufficient bills of indictment. State v. Benton, 275 N.C. 378, 167 S.E.2d 775 (1969); State v. Cannady and State v. Hinnant, supra.

II.
Because the State may seek to re-indict and re-try defendants, we think it appropriate to discuss one other assignment of error. Defendants contend that the trial court erred in denying defendants' motion to suppress and motion in limine to suppress all evidence and items seized during the search. Defendants allege that the affidavit offered in support of the search warrant was fatally defective because (1) the information contained in it was stale and (2) it failed to implicate the premises to be searched. We agree. There were no facts in the affidavit closely related to the time of its issuance that justified a finding of probable cause at that time. Neither was there any information in the affidavit to support a finding of probable cause that drugs were being stored or that drug-related activities were taking place at 335A Temple Road.
Search warrants may only be issued upon a finding of probable cause for the search. U.S.Const. amend. IV; G.S. 15A-245. Proof of probable cause must be established by facts so closely related to the time of issuance of the warrant so as to justify a finding of probable cause at that time. 68 Am.Jur.2d Searches and Seizures § 70. Our court has recently held:
The general rule is that no more than a "reasonable" time may have elapsed. The test for "staleness" of information on which a search warrant is based is whether the facts indicate that probable cause exists at the time the warrant is issued. Sgro v. United States, 287 U.S. 206, 53 S.Ct. 138, 77 L.Ed. 260 (1932); State v. King, 44 N.C.App. 31, 259 S.E.2d 919 (1979).
State v. Lindsey, 58 N.C.App. 564, 565, 293 S.E.2d 833, 834, cert. denied, 306 N.C. 747, 295 S.E.2d 761 (1982). Our court suggested that an interval of two or more months between the alleged criminal activity and the affidavit is generally an unreasonably long delay. Id. at 566, 293 S.E.2d at 834.
The affidavit offered to justify a finding of probable cause consisted of a report on the comings and goings of certain individuals (including defendants) to and from 335A Temple Road, and a recitation of defendants' prior drug-related arrests and their reputations. When SBI agents stopped and searched the individuals after they left 335A Temple Road, they were not in possession of marijuana, and nothing else appearing, their activities as stated in the affidavit cannot justify a finding of probable cause. That leaves the recitation of defendants' prior drug-related activities to support the finding of probable cause. Defendant Goforth's arrest for possession of marijuana was in 1977; there was no arrest information on defendant Reynolds; and defendant Rosokoff's indictment for a drug violation in Florida was in 1975. Clearly, a recitation of the prior arrests of these defendants, *493 even in combination with the alleged comings and goings to and from 335A Temple Road, failed to provide timely information on which to base a finding of probable cause.
In addition, this affidavit failed to implicate the premises to be searched. In order to show probable cause, an affidavit must establish reasonable cause to believe that the proposed search for evidence of the designated offense will "reveal the presence upon the described premises of the objects sought and that they will aid in the apprehension or conviction of the offender." State v. Campbell, 282 N.C. 125, 129, 191 S.E.2d 752, 755 (1972). Probable cause cannot be shown by an affidavit which is purely conclusory and does not state underlying circumstances upon which the affiant's belief of probable cause is founded; there must be facts or circumstances in the affidavit which implicate the premises to be searched. State v. Rook, 304 N.C. 201, 221, 283 S.E.2d 732, 744-745 (1981), cert. denied, 455 U.S. 1038, 102 S.Ct. 1741, 72 L.Ed.2d 155 (1982).
In order for an affidavit to establish probable cause sufficient to justify issuance of a search warrant, a recital of underlying facts or circumstances is essential. United States v. Ventresca, 380 U.S. 102, 85 S.Ct. 741, 13 L.Ed.2d 684 (1965). The only statements in the affidavit that concerned 335A Temple Road were: (1) the conclusory statement that 335A Temple Road was being used "for the storage of drugs and the furtherance of their illicit drug operation," and (2) the fact that two individuals that a confidential informant said were going "to Black Mtn. to purchase marihuana" [sic] later appeared at 335A Temple Road. We hold that these statements do not recite facts or circumstances sufficient to implicate the premises at 335A Temple Road as a place where drugs were being stored or where drug-related activities were taking place. Thus, the search warrant was invalid, and the fruits of the search were not competent evidence. Mapp v. Ohio, 367 U.S. 643, 81 S.Ct. 1684, 6 L.Ed.2d 1081 (1961); State v. Campbell, supra; G.S. 15A-974.
The evidence obtained upon execution of the invalid search warrant is not admissible against these defendants.
Based on our holding in part I above, the judgments are arrested.
HEDRICK and BECTON, JJ., concur.
