“I’m not sure if it’s the thyme (time) or the plaice (place)” is a popular food pun. “This is neither the thyme nor the plaice” was posted to the newsgroup rec.arts.sf.written.robert-jordan on July 1, 1996.
 
“I’ve got loads more jokes about herbs and fish… But now is neither the thyme nor the plaice” was posted to Twitter on March 13, 2009.
       
 
Wikipedia: Thyme
Thyme (/ˈtaɪm/) is an evergreen herb with culinary, medicinal, and ornamental uses. The most common variety is Thymus vulgaris. Thyme is of the genus Thymus of the mint family (Lamiaceae), and a relative of the oregano genus Origanum.
 
Wikipedia: Plaice
Plaice is a common name used for a group of flatfish. There are four species in the group, the European, American, Alaskan, and scale-eye plaice.
 
Commercially, the most important plaice is the European. This is the principal commercial flatfish in Europe; it is also widely fished recreationally, has potential as an aquaculture species, and is kept as an aquarium fish. Also commercially important is the American plaice.
 
The term plaice (plural plaice) comes from the 14th century Anglo-French plais. This in turn comes from the late Latin platessa, meaning flatfish, which originated from the Ancient Greek platys, meaning broad.
 
Google Groups: rec.arts.sf.written.robert-jordan
A Major Character Must Die
Dave Hemming
7/1/96
(...)
This is neither the thyme nor the plaice for another cascade.
     
18 August 2001, The Daily Telegraph (London, UK), “Best-sellers,” pg. 2:
5 Rick Stein’s Seafood Lover’s Guide by Rick Stein (BBC, pounds 20) 1,654 The thyme, the plaice
 
Google Groups: alt.humor.puns
Is Adolph in ?
nemo
8/25/03
(...)
This is hardly the thyme or the plaice, so we’ll skate over that one for now!
 
Twitter
Richard Peacock
‏@richardpeacock
I’ve got loads more jokes about herbs and fish… But now is neither the thyme nor the plaice. #rednoseday
11:22 AM - 13 Mar 2009
 
Twitter
Todd Halfpenny
‏@toddhalfpenny
I was going to make herb related pun joke today… but this isn’t the thyme or the plaice! (credit to @MarcusScheel for the punchline)
3:42 AM - 20 Jan 2010
 
Twitter
This Is Not Normal
‏@JonnieMarbLes
Cooking is all about finding the right fish & herb accompaniments. There’s a thyme and a plaice for everything.
8:02 AM - 3 Jul 2010
 
4 February 2011, The Sun (London, UK), “Have a Laugh,” pg. 20:
I WAS about to cook my favourite fish when my wife turned up with parsley and cod.
 
I thought: “This isn’t the thyme or the plaice.”
   
Twitter
cluedont
‏@cluedont
This is not the thyme or the plaice for a food-based homonym.
10:24 AM - 28 Nov 2012
 
Reddit—TBFC
Have you heard the joke about the Fish and the herb? (self.TBFC)
submitted January 3, 2013 by ytguy
It’s not the thyme or the plaice!
 
Reddit—Jokes
I have a joke about fish and herbs.
submitted May 11, 2014 by NumpteyMan
But I don’t think now is the thyme or the plaice to tell it.
 
Reddit—Jokes
Why couldn’t the man open a fish and herb shop?
submitted July 3, 2014 by RCWC
Because he didn’t have the thyme or the plaice.
 
Facebook
Dad Jokes
February 16, 2015 ·
I’ve got a great joke about herbs and fish, but now isn’t the thyme or the plaice.
 
Twitter
Crap Jokes
‏@TheCrapJoker
I was gonna send my awful ‘Fish in Herb Sauce’ back to the chef..
But I’m not sure sure if it’s the thyme or the plaice.
1:15 PM - 12 May 2015