The company is putting the technology to use for the 2014/15 season - with the introduction of its Planting Companions range.
Production director Jeremy Sharp said: "The technical developments and investment made in the machine seed filling process now means Mr Fothergill's can combine 80 per cent of its seed varieties in any twin combination."
The launch follows 2013/14's Value Twin Packs. Pairings are carrot and spring onion to deter carrot and onion fly, lettuce and chervil to deter aphids and slugs, cabbage and thyme to repel cabbage whites, and tomato and marigold to combat whitefly and aphids.
In other developments, Johnsons has introduced a range of Microgreens for the 2014/15 season.
Mr Fothergill's has also teamed up with the makers of the Buzzy garden range to launch a selection of six gardening gifts and kits for the 2014/15 season under the Garden Time brand.