Basic principals and guidelines for seed saving open pollinated vegetable varieties

Note: All heirlooms, amateur and conservation varieties are open pollinated


The following text is meant as a guide to help achieve a successful outcome for saving seeds. This subject is big because many plant species have their own particular requirements concerning seed saving and many books have been written extensively on the subject. For more in-depth technical information please see bottom of page for list of literature.

Setting the scene

Open pollinated varieties:

  • are naturally pollinated – by insects or wind; no enforced pollination or in-breeding.
  • contribute to food plant biodiversity (of which we have lost 80% in Europe this last Century)
  • are adaptable – they are genetically variable and therefore able to adapt to climate change, to particular landscapes and environmental conditions and evolve along with them.
  • can be seed-saved by farmers, market gardeners, home gardeners and allotment holders.
  • seed saved will breed true-to-type plants, resembling parent plants – unlike hybrids.
  • can be used to develop local varieties.
  • are of course non-GM, non-hybrid and non-patented.

Plant species and plant varieties

The word species concerns the whole range of for example carrots,onion and tomatoes. But within the carrot,onion and tomato species we find numerous carrot, cabbage and tomato varieties. These we may know by name and can buy from seed companies and garden centres.

The seed: the seed hides everything about itself as a plant until it is released into its entire form. Know where your seed has come from, whether it came from a friend or from a seed catalogue or seed swap and seek to know its name. This will give you some idea and hopefully assurance of what to expect from it.
As a principle nature relies on diversity to maintain herself and her survival possibilities and plants readily cross pollinate where they can. Even self-pollinated types are not 100% self-pollinating 100% of the time which leads to the occasional mixing of characteristics which can be a bonus or not as case may be.
As people we have the tendency to do just the opposite, to create uniformity and homogenise for the sake of convenience and simplicity. This is seen so clearly in the case of breeding F1 hybrid varieties. F1 hybrid breeding is all about homogenisation and uniformity, a procedure which discards diversity in the process. Therefore to bring back genetic diversity we must strive to find the balance which on the one hand maintains genetic diversity and on the other distinguishes variety, upholding productivity. All of which was done before the hybrid era. Working with open pollinated varieties achieves this wonderfully and gives us the flexibility needed.

Your choice of seed crop, 1: Allotment or home gardeners.
There are several factors to consider when saving for seed. For small areas like allotments and home gardens self-pollinated species are easiest to manage since they don’t require many plants for saving seeds and also they don’t readily cross pollinate. However make sure you know whether your species does require protection from another same species growing close by. See seed saving below for individual species requirements.
Having said that it may be possible to obtain enough good plants from cross pollinated species in an allotment or home garden situation to select out the best specimens and keep for seed.

Your choice of seed crop, 2: Professional vegetable growers.
The professional grower is usually in a good situation as high numbers of plants are easily achieved whether these are self-pollinated or cross pollinated species. Here up to several hundred plants can be selected for seed without difficulties.
Cross pollination from neighbouring farms or gardens is something to be aware off. Especially with wind pollinated species like maize / sweet corn and the beet family but also insect pollinated crops of the brassica family and other species. See specific crops on seed saving below.

Pure Line variety. All varieties which we can buy from seed catalogues or garden centres have been bred to be distinctly different from other varieties. These are called pure line varieties and for identification reasons have been given names, which help us all to know our varieties. It is important to keep maintaining our open pollinated pure line varieties so we can continue to enjoy and appreciate the characteristics associated with them.

Crop familiarity: It is best if you are familiar with the variety or type of vegetable, cereal or other crop which you want to grow for seed. For example, carrots are identified according to types such as Nantes, which are early sowing and early maturing. Chantenays, which are later sown but are early main crops. Berlicums and Autumn king types which are also later sowing types and recognised as main storage crops. Your lettuces for example are categorised as butterheads, crisp heads, cos types, loose leaf types and batavias. Each one representing their particular characteristics and values. These are all important to be aware of.
You need to be able to distinguish your type by its size, shape, skin colour and texture, flavour if possible, foliage attachment, colour, how many weeks and months to maturity and note these down for yourself. These are observations which make a good gardener / grower in any case.

Vegetable plant propagation

When setting out to save seeds its crucial to know how your species propagates.
Our vegetables reproduce either through cross pollination (cp), self-pollination (sp) or a combination of both (cp/sp). Most species are insect pollinated with a few being wind pollinated like sweet corn, spinach, beet root, chards and sugar beet.
Cross pollinated plants require usually a minimum of 25 –30 plants to maintain genetic diversity within cultivars. A population of 25-30 plants carry many characteristics that make up a cultivar so the more plants the better to ensure proper vigour and upholding of characteristics.
With self-pollinated plants it is different, here just a few will do but as each plant may genetically be a little different it is recommended to save several plants to get a mix of seeds.

Most plants are perfect flower plants or hermaphrodites with both pollen producing stamens and with stigmas to carry the pollen to its seed bud within the flower where the fruiting part / seed will develop.
Some plants are monoecious like sweet corn, courgettes and pumpkins which mean they have separate male and female flowers on their plants. And dioecious plants like true spinach and asparagus for example are either male plants producing only pollen or female plants, producing only the fruiting / edible part. This is important to know when growing plants for their seeds.

Plant selection

This is in fact breeding or maintenance breeding, keeping your variety by saving its seeds.

There are several factors effecting plant growth. Environmental factors like warmth, light, water, soil types and soil fertility all affect the plant in its phenotype, the phenomena shaping the plant. Then genetic factors determine the plant’s ability to reproduce itself according to its own make up and its interaction with the environment. Plant health, vigour, plant size and tolerance of diseases under adverse circumstances depend also on its genetic makeup and capability. The environment and genetic makeup of a plant has an interactive relationship.

Once you have chosen your crop for seed, mark out the best specimens at point of harvest.  Keep the most vigorous and healthy looking plants for seed.  Make sure you keep your variety true to type by selecting plants that display similar traits to one another.  Keep a notebook or seed diary for information, dates and observations relating to the crop to save seed from. It will come in useful.

Seed drying

Seeds keep best when their humidity / moisture level is low. A general rule is if the sum of relative humidity + farenheit is below 100. For example 60 farenheit and 37 % humidity then the seeds are stored well.

Traits to bear in mind when selecting your seeds for saving

Plants size, shape, skin smoothness, inner colour, outer and inner texture, flavour, scent of edible root, scent of leaf, fruit and seed parts. Shape, size and colour of plants leaf system, leaf gestures whether upright, fanning out, horizontal, open, closed, compact, rigid, semi rigid or flexible is also important. Further are disease tolerance, soil moisture tolerance, air and soil temperature tolerance, soil type and soil fertility utilisation ability, daylight altitude and latitude tolerance. Within all of those lie numerous variations besides.

Seed saving literature: Recommended.

The Organic seed grower: A farmers Guide to Vegetable Seed Production.

John Navazio. ISBN (hardback) 978-1-933392-77-6

Vegetable seed production, 2nd edition by Raymond A.T. George

CABI publishing ISBN: 0 85199 336 2

‘Seed to Seed’, by Suzanne Ashworth, ISBN, 0-9613977-7-2

‘Seed Savers’ Handbook’, by Jeremy Cherfas, Michel and Jude Fanton

ISBN: 1=-899233-01-6