An heirloom plant
, heirloom variety
, or (especially in the UK
) heirloom vegetable
is a cultivar
that was commonly grown during earlier periods in human history, but which is not used in modern large-scale agriculture
. Many heirloom vegetables have kept their traits through open pollination
, while fruit varieties such as apples have been propagated over the centuries through grafts and cuttings. The trend of growing heirloom plants in gardens
has been growing in popularity in the United States
over the last decade.
Before the industrialization of agriculture
, a much wider variety of plant foods was grown for human consumption. In modern agriculture in the industrialized world
, most food crops are now grown in large, monocultural
plots. In order to maximize consistency, few varieties of each type of crop are grown. These varieties are often selected for their productivity, their ability to withstand mechanical picking and cross-country shipping, and their tolerance to drought, frost, or pesticides. Nutrition, flavor, and variety are frequently secondary and tertiary concerns, if a concern at all. Heirloom gardening can be seen as a reaction against this trend. In the Global South
, heirloom plants are still widely grown, for example in the home gardens
and Southeast Asia
, although their future is uncertain.
Motivation to grow
Heirloom growers have different motivations. Some people grow heirlooms for historical
interest, while others want to increase the available gene pool
for a particular plant for future generations. Some select heirloom plants due to an interest in traditional organic gardening. Many simply want to taste the different varieties of vegetables, or see if they can grow a rare variety of plant.
There is no consensus as to how old a plant variety should be before it can be considered an heirloom. Many gardeners consider 1951 to be the latest year a plant can have originated and still be called an heirloom, since that year marked the widespread introduction of the first hybrid
varieties. Some heirloom plants are much older, some being apparently pre-historic
. Usually, a plant is not called an heirloom if it is grown widely and commercially, regardless of how old it is.
To be an heirloom, a plant must be "open-pollinated", meaning it will grow "true to type" and produce plants like the parents from seed. This excludes nearly every hybrid. Open pollination allows the same cultivar to be grown simply from seed for many generations.
Typically, heirlooms have adapted over time to whatever climate and soil they have grown in. Due to their genetics, they are often resistant to local pests, diseases, and extremes of weather.
are sometimes collected (nondestructively as small leaf cuttings) from vintage homes and from cemeteries
, where they were once planted at gravesites by mourners and left undisturbed in the decades since.
UK and EU law and national lists
In the UK and Europe, it is thought that many Heritage vegetable varieties (perhaps over 2000)
have been lost since the 1970s, when EU laws were passed to make it illegal to sell any vegetable cultivar that is not on a national list
of any EU country. This was set up to help in eliminating dishonest seed suppliers selling one seed as another, and to keep any one variety true. Thus there were stringent tests to assess varieties, with a view to ensuring they remain the same from one generation to the next.
These tests (called DUS) encompass Distinctness, Uniformity and Stability. But since some heritage cultivars are not necessarily uniform from plant to plant, or indeed within a single plant - a single cultivar - this has been a sticking point. Distinctness has been a problem, moreover, because many cultivars have several names, perhaps coming from different areas or countries (eg. Carrot cultivar 'Long Surrey Red' is also genuinely known as 'Red Intermediate', 'St. Valery' and 'Chertsey'.). However, it has been ascertained that some of these varieties that look similar are in fact different cultivars. On the other hand, two that were known to be different cultivars were almost identical to each other; thus the one would be dropped from the national list in order to clean it up (eg. Onions 'Up-to-date' and 'Bedfordshire Champion' looked very similar, and 'Up-to-date' was dropped. Later, it was found that 'Up-to-date' has very good disease resistance, whereas 'Bedfordshire Champion' does not. Fortunately, 'Up-to-date' is on a seed-saver list).
Another problem has been the fact that it is somewhat expensive to register and then maintain a cultivar on a national list. Therefore, if no seed-breeder or supplier thinks it will sell very well, no-one will maintain it on a list, and so the seed will not be re-bred by commercial seed breeders.
In recent years, progress has been made in the UK to set up allowances and less stringent tests for heritage varieties on a 'B' national list, but this is still under consideration.