In our area there are lots of growers who use the label naturally grown without being certified. None of the growers here are listed on the CNG website list of farms, https://certified.naturallygrown.org/.  I've always believed that naturally grown is a generic description, without any legal or regulatory requirements. The certification may be valuable for some growers, but judging by our local farmers market producers, is not something mandatory.

Renais

all plants are naturally grown. it is a generic term. put a seed to dirt, nature takes over, even if you use chemicals. If you choose to use organic practices, CNG is an alternative to organic certification.

While individual markets usually set their own rules, this subject is typically debated often and often just ignored. One market I'm in stipulates that if you display "Organic" then you must be OMRI certified. Seems like the governments can't even agree on how to define these terms. Nobody wants to use the term "Unnatural" which sums up the system now under review.

The way I understand it. You can not use "organic" unless you are certified, under penalty of a $5,000 dollar fine from the FDA. "naturally" can be used without any fine, although I wouldn't be surprised if the FDA changes that in the near future.