Rod is our Seed Buddy

BPCG has offered one of its volunteers the opportunity to take part in a new Seed Buddy training programme being run by Sustain and London Freedom Seed Bank (LFSB). This involves the prospective Seed Buddy attending a mandatory four training sessions on good seed saving skills, wildlife gardening, and visiting and supporting a garden.

The latter session will be important as the Seed Buddy will be partnered-up with two Capital Growth sites to help them develop their own seed saving skills. For those who don’t know, Capital Growth is a project of the charity Sustain: The alliance for better food and farming. There are currently 2500 Capital Growth sites registered in Greater London, although around 1000 are inactive: BPCG is number 1956. So our Seed Buddy will be working in partnership with the Community Gardener and volunteer team here to support the charity’s educational remit by demonstrating effective seed saving techniques.

Training is being funded by Sustain and the seed saving session was led by Catrina Fenton and Claire Pritchard from the Heritage Seed Library (HSL), part of Garden Organic (formerly HDRA), and which was set-up in 1975 in order to protect hundreds of vegetable varieties endangered by new EU regulations. They currently hold 800 varieties in their collection.

Threat to plant biodiversity continues as regulations make it financially unviable for most seed companies to stock more unusual varieties since the cost of registering them for sale is greater than the money that can be made from them since they are typically sold in smaller quantities. Also, the registration process for inclusion on the UK National List or in the EU Common Catalogue requires seed varieties to pass the DUS test: D = distinct from any other variety; U = uniformity in all the plants grown from that seed; and S = stability in this uniformity over generations. As a consequence, the system favours large-scale growers whose requirements are crops which ripen at the same time for ease of mechanical harvesting; which are resilient enough to cope with transportation and supermarket handling; and which show esthetic uniformity and familiarity. Flavour will be a minor factor in the selection process.

Therefore seeds held in seed banks are there as they do not conform to these specifications or are no longer registered for financial reasons. As a result, seed banks are unable to charge for the seeds they hold. The HSL circumvents this by charging for membership instead and then distributing seeds free of charge to their members; others, such as the LFSB, are completely free. But seed banks do need dedicated growers of seed in order to replenish their stock each year. A skills gap was identified in the Greater London area which led to the LFSB being set-up to train a new generation of seed savers in order to create a supply of locally-grown and adapted seeds. The only other initiative receiving funding with this regard is the Connected Seeds and Sensors project being run by Queen Mary University of London, but there are various other small scale initiatives dotted around London’s small but passionate community of food growing sites; and without the dedication and hard work of organisations such as the HSL and the LFSB, together with their army of dedicated seed growers, many varieties would be lost forever.

Seeds held in community seed banks are open-pollinated – that is, they are naturally pollinated either by insects or wind. Open-pollinated seeds are distinct from F1 hybrids in a number of important ways: they will grow true to type and so can be saved by gardeners for future sowings; they contribute to plant biodiversity due to their wide genetic heritage; and this genetic diversity means they are highly adaptable to their environment, giving the gardener the opportunity to actively select for varieties which grow well in their garden and to changing climatic conditions. F1 hybrids on the other hand are developed from two heavily inbred parent plants, have very limited genetic adaptability and are either sterile or will produce offspring which show wild variation from the seed collected. Only the seed developers knows which varieties were crossed to produce the hybrid and this is kept a closely guarded secret for financial reasons as they want the gardener to keep buying seed from them. F1 hybrids are developed principally for the commercial market with all the qualities which facilitate ease of mass-harvesting and sale, qualities which the small-scale grower is not really interested in. Both open-pollinated and F1 hybrid seeds are distinct again from Genetically Modified (GM) seed where natural selection is bypassed entirely and the seed is altered instead in a laboratory at the genetic level by the manipulation of genes, sometimes involving the splicing in of genetics from species of life which have nothing to do with the original plant. GM seed corporations now have sufficient financial power to lobby governments to pass laws in their favour with promises of food security for an ever increasing world population. The reality is farmers are giving up their biodiverse seed heritage garnered over countless generations through the sacrifice and careful guardianship of their bloodline ancestors for a promised bounty that has yet to materialise and which has instead financially indebted entire communities to faceless individuals in boardrooms whose overriding interest is profit.

Open-pollinated seeds saved by seed banks can fall under one of the following categories:

  • Landrace – these have been domesticated by growers from wild varieties and, thanks to the natural genetic diversity inherent in the seed, have adapted over time to soil type, fertility, water availability and the general climate of their environment, as well as being selected for flavour, ripening times, storage, etc.
  • Heirloom – these are seeds handed down through generations of growers and are varieties found to have been of sufficient value to be saved. They are not necessarily tied to a specific locality, unlike landrace.
  • Ex-catalogue – varieties which have been removed from seed supplier catalogues or are no longer registered for sale but have been saved by growers.

The two principle rules for growing vegetable seeds which hold true to their type (open-pollinated) are:

  • remove all undesirable plants (roguing) which do not show the expected growth traits and vigour which the variety should display and;
  • prevent cross-pollination from other varieties.

Now for a little basic botany. The flower of a plant is where sexual propagation takes place. Apart from the petals, which act to advertise and encourage pollination, the two most important elements of a flower are:

  • the stamen – said to be the male part of the flower, consisting of a filament on the end of which is an anther from which pollen is released;
  • the pistil – this is the female part consisting of a stigma, a sticky surface which receives pollen; the style, which holds the stigma in a receptive position and down which the pollen grain will send a pollen tube; and at the base of the style is the ovary which contains one or more undeveloped seeds or ovules which are fertilized via the pollen tube; in most flowering plants, it is the ovary which will eventually swell to form a fruit within which are contained the viable seeds.

Flowers can be classified in one of two ways:

  • perfect – each flower contains both male and female parts, e.g. Pisum sativum – peas;
  • imperfect – each flower contains within it either the male or female part but not both;
  • plants which carry both male and female imperfect flowers are called monoecious, e.g. Cucurbita – squash;
  • plants which carry their male and female flowers separately on different plants are called dioecious, e.g. Spinacia oleracea – spinach.

Vectors of pollination are:

  • self-pollination – this can occur in most perfect flowers where the anther may sweep past the stigma, as occurs in Nasturtium, or the stigma grows past the anther, as in most Solanum lycopersicum (tomatoes); plants which pollinate in this way are known as inbreeders and are the easiest form from which to save seed, so precautions for preventing cross-pollination are mostly not relevant;
  • cross-pollination – necessary for those perfect flowers which cannot self-pollinate, i.e. are self-incompatible, and for all imperfect flowers whether on monoecious or dioecious plants; pollination is achieved either through the vector of wind or insect/animal pollinators; plants which pollinate in this way are known as outbreeders and are more prone to cross-contamination from similar varieties of species so more rigorous isolation measures are required to prevent this; examples are Brassica (cabbage, kale, etc) and Allium spp. (onions, garlic, etc),

Methods of preventing cross-pollination are:

  • growing only one variety of any given species of outbreeding vegetable so that all the pollen reaching the female flowers will be only of that variety, thus preserving its purity;
  • it is important to know who might be growing vegetables near you as they may also have the same species but a different variety on the go, in which case there are the following options:
  • grow your crop further away – each species of outbreeding vegetable has a minimum isolation distance to prevent cross-pollination, e.g. Phaseolus coccineus, the runner bean, requires an isolation distance of 800m;
  • if this is not possible, then the seed saver will need to consider isolation barriers, such as fleece cages, which are advanced seed saving techniques;
  • alternatively, one might consider isolation by time – that is, growing an early flowering variety followed by a late flowering variety so that the opening of their flowers does not coincide, but this isn’t so easy with the short British growing season.

The budding seed saver armed with all this knowledge will hopefully arrive at the end of their year with a crop of plants ready for harvesting for seed. Each species requires a particular technique for extraction and some are easier than others, e.g. compare broad beans to carrot seed. The extracted seed is around 10-15% water which will then need to be reduced to around 5% in order to prolong its viability when stored. Air drying in an area without full sunlight or heat is fine for short to medium term storage. Dessicants such as rice or silica gel provide various advantages over air drying such as reducing the time required to decrease the seeds water content and thus the chances of mould growth on the seed.

Once dried, seeds being used the following year only need be stored in a cool, dry place in an airtight container; for longer term storage, a fridge or freezer can be used. Advanced long term storage techniques not only provide conditions where seed water content and temperature are closely regulated but also the oxygen around them is replaced with an inert gas, such as nitrogen, in order to further slow down the cellular respiration processes within the seed which determine their longevity. Despite this, some seeds do not store well, even for a short period of time, such as Pastinaca sativa, the parsnip, which should be used fresh. Therefore the seed of each species has an optimum storage time beyond which germination rates will drop.

It is vitally important to label the container the seeds are in with their species, variety, date and location of harvest, plus any other comments about the variety’s growth traits. When the time comes to sow the seeds, there are a couple of recommendations given:

  • allow the container and its contents to come to room temperature before opening;
  • allow the seeds to ‘rest’ for a few days at room temperature and ambient humidity before sowing.

In this way the seeds will be able to reabsorb moisture naturally and not be ‘shocked’ thus improving their chances of germination.

And so the turning of the seasons continue, each year offering us yet another opportunity to be active participants in safeguarding the heritage left to us by our ancestors. For some this is a chain of guardianship that has never been broken; for others this is esoteric knowledge, freshly discovered and eagerly consumed, reshaping their perception of the world and their place within it; and, alas, for others it is a danger to their corporate profitability.

When we are better informed we can make better choices, so here are a few links to websites which may help in this process.

To register for free as a Capital Growth site and apply for a Seed Buddy, see:

For more information on the Heritage Seed Library, see:

For the HSL seed saving pdf which will be a point of reference for Seed Buddies, see:

For information on the work of the London Freedom Seed Bank, see:

For more information on Connected Seeds and Sensors, see:

For more information on EU seed law, see:

For more information on open-pollinated seeds, see:

For three documentaries on how the erosion of seed diversity through GM is affecting indigenous agricultural communities, see:





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