Investors looking to short gold have missed their chance, commodities trader Dennis Gartman said Monday.

"I've been long in yen terms—everybody knows that—for quite a long period of time," he said. "I'm about to get long of gold in euro terms at the same time. And I do think the time for being short of gold is past."

Gold prices ended the day lower after a sudden drop earlier in the day, settling at $1,238 an ounce.

(Read more: Gold ends lower at $1,238 after sudden early tumble)

On CNBC's "Fast Money," the editor and publisher of The Gartman Letter said he doesn't expect a jump in gold prices yet, either.

"It's not quite time to be bullish of gold in dollar terms, but it's getting closer than it has been," he said. "Gold has taken a lot of ill news. It's fallen quite a long way. The merchants are all net long, which is something we haven't seen for a long ... time. And the last time the merchants got long was at gold's bottom."

(Read more: Sudden gold plunge has traders looking for answers)

Gartman said he would be watching the trend line in euros, as well as in Japanese yen, for a sign to expect higher prices.

"If gold can go through 140,000 yen per ounce, which it hasn't been able to get through for a while, I'll be even more impressed," he said. "If you missed the first $20 in gold, you won't be missing much. So, you've got to break trend lines. They haven't done it yet, but they're putting those downward-sloping trend lines to test from beneath, and that's important."

—By CNBC's Bruno J. Navarro. Follow him on Twitter @Bruno_J_Navarro.