Any gardener finding it difficult to cultivate modern hybrid varieties of lettuce should switch to more traditional types, it has been claimed.
Greenhouse and garden growers may find older versions such as Bronze Arrow and Rouge dHiver are more resilient, after the Royal Horticultural Society reported on a recent Garden Organic study.
The research found 11 of the top 12 best-performing varieties of lettuce were heritage types, with 1930s favourite George Richardson being bested only by the modern Kitare.
Horticulturalists taking part in the study expressed their bewilderment at the results and suggested further study could lead to a resurgence in popularity for the traditional leaves.
"It wasnt what I expected," lead researcher Phil Sumption told the RHS.
"When you grow commercially you tend to always go for the latest new varieties."
Gardeners looking to grow a heritage lettuce of their own may be able to source seeds from the library at Garden Organic.
The organisation recently said growing a patch of flowers next to a section of untended garden was a good way to encourage bees.