After the shocking decision by the Federal Reserve to forgo tapering its monetary stimulus program, investors are now asking when it might begin. Dennis Gartman says it could be a long wait.
"Going forward, we just have to keep an eye—as the Fed has told us—on unemployment and until that number gets below 6.5 percent, we can expect the Fed to do very little." Gartman, the founder of the closely watched Gartman Letter, told CNBC Europe's "Squawk Box" on Thursday.
"We're going to have to be deep-diving into the monthly data even more than we have in the past, and we're going to find out that we need. Maybe 200,000 or 225,000 or maybe even 250,000 in monthly nonfarm payroll numbers before the Fed's going to be comfortable with reducing the amount of accommodation."
Gartman said he was not surprised that the Fed had done nothing. "I said the Fed would do very, very little at all other than changing its rhetoric and [Fed Chairman Ben] Bernanke has made certain that we understand how data determinant the Fed would be going forward."
On Wednesday, the Fed reiterated its 2.5 percent inflation and a 6.5 percent unemployment rate—currently at 7.3 percent—as the minimum levels for reducing its monthly bond purchases.
Gartman was not so sure inflation was as important for the Fed, however, saying the central bank appeared "sanguine about the inflation numbers almost as if that was a secondary thought. The focus is clearly on the employment numbers."
Bernanke said Wednesday the central bank wasn't ready to cut back on its stimulus because a tightening in financial conditions could hurt the economy and employment.
(Read more: No taper! Did Bernanke fool the Street?)
Using this measure as a taper gauge, the decision not to taper is not entirely surprising. Job growth was less than expected in August as the U.S. economy added 169,000 positions. In June and July, the nonfarm payroll numbers showed a mixed picture with 195,000 and 162,000 jobs added respectively.
(Read more: Jobs growth misses high hopes; unemployment rate drops to 7.3%)
The decision by the Fed saw U.S. markets soar to all-time highs on Wednesday while bond yields retreated. "[The response by markets was] very logical," Gartman said. "The Fed has told you that another $85 billion a month will be rolling into markets for the next several months, stock prices have to go up, the bond market prices have to go higher and yields fell yesterday. Was the market responding logically? Yes, it did exactly what it should do."
(Read more: Fed's 'no' to taper sends stocks rising)
As investors prepare for Bernanke to leave the post in January, Gartman said that focus would now be on Janet Yellen, the Fed's current vice chairwoman after Larry Summers dropped out of the race last weekend.
Gartman said the dynamic between Yellen and Esther George, the hawkish president of the Kansas City Fed who has expressed concern about the risk of higher inflation as a result of Fed's aggressive monetary policies in the past, would be closely watched in future.
"Those will be the voices that we pay all our attention to after the turn of the year. Miss George is clearly the hawk on the committee while Yellen will be the dove on the committee, and we do have to defer to Miss Yellen; she will be the chairman. It'll be interesting to see the debates around those two."
—By CNBC's Holly Ellyatt, follow her on Twitter @HollyEllyatt.