So what exactly are Heirloom Seeds?

It can all get a bit confusing for the beginner home-garden vegetable grower when the time comes for choosing their vegetable varieties and selecting their seeds for planting. There is also a lot of (mis)information out there regarding Organic seeds, GMO's, Hybrids, Heirlooms etc, so we figured that a few explanations might come in handy (please see our separate page for more info on GMO's).

Organic Seeds

Heirloom and Heritage Seeds

Open Pollinated Seeds

Self Pollinated Seeds

Hybrid Seeds


Organic Seeds

Organic seeds are those harvested from plants grown without the use of any chemical pesticides, herbicides, fertilisers or any other chemical treatments. The seeds themselves are also not treated with any of the chemicals that are generally used by commercial seed companies to protect their seeds against diseases, increase germination rates or increase their shelf life.

Certified organic growers have to pass inspection by a controlling body every year to prove that their plants are grown and harvested under strict organic conditions. Read more on this organic certification process on our Seed Symbols Explained page.

Heirloom Seeds

The terms heirloom and/or heritage seed refers to open pollinated seeds/plants that have been handed down from generation to generation - generally a variety that is at least 40-50 years old, is usually no longer available in the commercial seed trade and that has been preserved and kept true in a particular region.

Obviously, these heirloom varieties have been saved because they have some real virtues to the home gardener. Classic examples would be heirloom tomatoes, which often have superior flavor, color or texture for home garden situations but might lack the holding ability (shelf life), uniform colour and shape, disease resistance or early maturity that would make them commercially viable.

Seed saving organizations and home gardeners have been the agents that have kept heirloom varieties in existence over time, as larger seed companies generally focus on hybrid varieties with commercial qualities.

Open Pollinated Seeds

Open Pollinated (OP) means that the plants are left for the bees, wind, or some other natural source to pollinate. Note that all heirloom varieties are open pollinated but not all open pollinated varieties can be considered heirlooms. OP seed is generally kept true to type through selection and isolation and their traits are relatively fixed, but they are also adapted for local conditions.

For example, if I grew the Brandywine variety of open pollinated tomato in our warm South African climate year after year and saved seeds only from the strongest and healthiest plants with the best tasting, earliest ripening fruits, I would have a locally adapted strain of Brandywine, slightly different to the Brandywine seed saved by a gardener in the colder European climate regions who had also been saving their seeds.

These climatic variations can of course result in very, very slight differences in shape, size, colour, taste etc of the local strain, and this can sometimes be a little confusing when there are so many 'versions' of the same variety.

The seeds of open-pollinated plants that are kept in isolation and are either self pollinated or pollinated by plants of the same strain/variety, will produce new generations that are (almost) identical to the parent plants. This is generally referred to as "breeding true" or "true to type".

But also note that if an OP variety is not kept in isolation and it is cross pollinated by another strain or variety then any seeds that are saved from that plant and then resown could result in a plant that has traits from both parent plants. Open pollination thus increases biodiversity.

Home gardeners may decide to cross pollinate a plant variety that has a great flavour with one that has an unusual colour or shape to produce a "new" variety. Once they have succeeded in getting that plant "just right" they would then isolate that variety for the following few generations (to stabilise the cross and ensure that it always breeds true) and over time, produce a new open pollinated variety. They may have to wait another 50 years or so until it could be considered an heirloom though ;-)

Self Pollinated Seeds

Some plants are primarily self pollinated and also breed true, so that even under open-pollination conditions the next generation will be (almost) identical to the parent plant. These self pollinated plants either have both male and female flowers on the same plant or they have both male and female reproductive organs in the same flower thus making cross pollination extremely unlikely.

But remember that even among these true breeding plants, some variation due to genetic recombination or due to mutation can produce a few "off types".

Hybrid Seeds

Hybrids are plants whose parents have been intentionally crossed so that desirable traits show up in the offspring, resulting in vegetables that boast bigger fruit, disease-resistance, or a whole host of other beneficial characteristics.

Unfortunately, since the hybrids available to us are usually designed specifically for commercial purposes, the taste of these hybrid vegetables has been often sacrificed for some other more industrial benefit (like bigger fruit, thicker skin to better withstand mechanical harvesting or a longer storage life).

Many hybrid seeds are relatively new crosses and you may see them labelled as F1 (first filial or first-generation hybrid) or F2 (the second filial generation after being crossed). The higher the number of generations after the cross, the more chance that these crosses have been "stabilised" and will then breed true. This would normally take more than 4-5 generations however so you can be fairly certain that seed from a F1 or F2 hybrid will not produce plants with identical qualities to the parent. This means that if, for example, you come across a hybrid tomato variety that you really like and that works for you, you would have to purchase the seed every year to grow the same plants.

You may be lucky and out of a hundred or so seeds saved from a hybrid, get one or two seedlings that turn out true to type. Do this for a few generations and you will eventually stabilise the seed, but plant and seed companies have recently begun patenting their crosses so that only they have the right to reproduce the hybrids they’ve developed.

Hybrids should not be confused with genetically modified organisms or (GMOs) which can be any plant, animal or microorganism which has been genetically altered using molecular genetics techniques such as gene cloning and protein engineering. Plants like maize/corn that has the pesticide 'Bt' gene engineered into its genetic makeup, to make it resistant to certain pests, are GMO crops.

Click here for more information on GMO's and why they are so bad.




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