Kings Seeds, founded in 1978, boasts the largest range of seeds in New Zealand.
Its seeds are also stocked in selected retailers nationwide and an extensive catalogue features more than 128 organically certified varieties.
Kings Seeds was the first company to introduce organically grown and internationally certified seed to the New Zealand home gardener market in 2000.
From its starting point of two overseas suppliers, it now receives a wide variety of organic seed from 10 national and international suppliers whose seed is organically grown and certified.
Its organic range has grown from 14 varieties in 2000 to 128 varieties in 2014 - with 24 of them ranking among their most popular lines.
Mr Martin credits his customers' growing awareness for the huge growth in organic seed sales.
"Consumers are becoming more educated around the health and environmental benefits of organics in general and that starts from the seed up.
"We have responded to this demand and are committed to expanding our organic seed range every season."
He said the team was proud of the new accreditation.
"A big thanks to the BioGro NZ team who did a thorough job of scrutinising our business to ensure that we met their strict criteria.
"We're extremely proud to have come through the process with flying colours."