Category: seed collection

Sowing Victoria

Posted on by andy.winfield

By Nicola Temple

A photo taken a couple of years ago – I
have a grasp on my son as he leans
over into the tropical pool to get a
good look. Victoria cruziana is in flower
as is the lotus above us.
Photo credit: Shelby Temple

For me, one of the highlights at the University of Bristol Botanic Garden is the giant waterlily (Victoria cruziana) that lives in the pond in the tropical glass house. Its enormous leaves, which can reach 2 metres in diameter, are studded with spines on the underside and always provide ample wow factor for visiting children (my own included).  

The plant is found in slow moving waterways in Brazil, Argentina, Paraguay and Bolivia – in places such as the Pantanal. Its pollination story is an interesting one in that it is pollinated by a beetle (Cyclocephata castaneal). Its white flowers give off a strong scent that attracts the beetles in the evening. The flower then closes around the beetles, trapping them in the flower overnight. The flower produces heat (thermogenesis), raising the temperature as much as 9oC above the ambient temperature outside, which means the beetles can maintain a high level of activity without using as much energy. It’s a thermal reward and the plant benefits as the active beetles will pollinate the flower. The pollinated flower opens the next evening, revealing a new light pink colouration to its petals. The beetles flee the flower and make their way to the next unpollinated flower.

Of course, this species of beetle isn’t found in the Botanic Garden, which makes pollination a bit more challenging. However, there are other insects in the Garden that have filled this niche and the plants have set seed over the last few years. However, this is the first year that staff at the Botanic Garden have tried to sow this seed and, so far, things are going well!
The seeds of Victoria cruziana are kept wet.
Photo credit: Andy Winfield

Replicating the natural environment

In its natural environment, the seeds from Victoria cruziana would be buried in the sediments, stirred up perhaps by grazing capybara and swirling river currents. It wouldn’t be until the high water levels following the rainy season had receded that the water temperature and the amount of light penetrating to the sediments beneath would be sufficient to prompt germination.

In the Botanic Garden, botanical horticulturist, Andy Winfield, first primed the seeds by scratching the tough seed coat with secateurs. The seeds were then sown into topsoil and covered with a layer of horticultural grit. The pots with the sown seeds were then placed in a container of water to a level about 10 cm depth above the seed. This replicates the approximate water depth in the natural environment. The water is heated to a temperature of between 30oC and 32oC; this is critical to start the germination process.

Andy scores the seeds with secateurs
before sowing.
Photo credit: Nicola Rathbone

Victoria cruziana grows around the edges of water bodies and in wetland areas where there is no forest canopy. In order to replicate the amount of daily sun it would be receiving in the tropics and sub-tropics, grow lights on a 12h on/12h off cycle were hung above the pots. Then the whole contraption was covered in plastic film to reduce evaporation and maintain humidity.

Andy had read that germination time is generally about 2-3 weeks in this type of scenario, but within a few days he noticed that the seeds were starting to send out roots and when I visited a week after sowing, the hypocotyledonous stems were clearly emerging from the seeds and shooting upwards toward the surface of the water. 

Preparing to plant Victoria out

At the moment, the water temperature in the pool in the tropical glasshouse is only about 14oC, far too chilly for Victoria. In the coming weeks, however, these plants are

likely to grow quite quickly. Andy and the rest of the team at the Garden will pot them on several

times, gradually reducing their water temperature. At the same time, Bristol temperatures will be increasing and the tropical glasshouse will start getting warmer, as will the pool. By the time the Victoria plants have a few decent leaves, the temperatures between the tropical pool and the plants will have become similar enough that Victoria can be put into the planters in the pond.

The annual light intensity here in Bristol is considerably less than Victoria cruziana would receive in South America. However, the long summer days here mean that during those months more solar radiation is received here in a single day than in tropical South America. This helps Victoria cruziana flourish in the Botanic Garden tropical pool over the summer and it will be worth a visit to see it in flower. See the series of photos below taken the day the seeds were sown.

Andy prepares the loamy mix for sowing.
Photo credit: Nicola Rathbone

The seeds are sown into a loamy mix.
Photo credit: Nicola Rathbone

The soil is covered with a horticultural grit.
Photo credit: Nicola Rathbone

The seeds are sown and are ready for immersion
in a nice warm bath.
Photo credit: Andy Winfield
The pots immersed in the warm bath.
Photo credit: Nicola Temple
Only one week after sowing, the embryonic stem
has emerged and is stretching for the surface.
Photo credit: Nicola Temple

Sources:

Seymour, R.S. and Matthews, P.G.D. 2006. The role of thermogenesis in the pollination biology of the Amazon waterlily 
     Victoria amazonica. Annals of Botany 98(6): 1129-35.

The Svalbard Global Seed Vault: a safe haven for seed

Posted on by andy.winfield

By Helen Roberts

Svalbard is a group of Norwegian islands located in the high Arctic and only 1,300 km from the North Pole. It is breathtakingly beautiful. The landscape is stark, unforgiving and wholly memorable. I visited these islands more than 16 years ago as part of a 6-week science expedition – I was part of a botanical group looking at the exceptionally low-growing Arctic Willow. 
Memories of that place are still strong today. Its beauty and sense of isolation is unique. The humdrum of everyday life is simply stripped away here. You are left with the landscape, weather and incredible flora and fauna. Although life became simple, the vastness of the place was exhilarating and I felt totally and utterly free. 
The stark landscape of Svalbard
Photo credit: Paul Williams [via Flickr CC BY-NC 2.0]

The Arctic is an ideal refuge for seeds

Within this unforgiving landscape, nestled deep within a mountainside, is a seed bank of global importance. It holds 12,000 years of agricultural history and contains the world’s largest collection of crop diversity. 
The Global Seed Vault is the brainchild of renowned scientist Cary Fowler, a former executive director of the Global Crop Diversity Trust. It started as a simple idea back in the 1980s in the spirit of global collaboration, and finally came to fruition in 2008 when the building was completed. However, building the collection within is ongoing.
Svalbard Global Seed Vault
Photo credit: Amber Case [via Flickr CC BY-NC 2.0]
The facility currently holds about 850,000 different varieties of seed and acts as the back up for seed banks across the globe. This is a collection that is vastly important for food security and the safeguarding of crop diversity. Those 850,000 packets of seed represent more than 5,000 species and nearly half of the world’s most important food crops, from cereal and rice to unique varieties of legumes. The seed deposits come from over 60 different institutions and represent nearly every country in the world. 
The chosen location of the global seed vault is an interesting story. It needed to be located somewhere safe from both potential natural disasters and human conflict. Svalbard itself is a safe place to store seed both in terms of physical and social factors. Svalbard’s remoteness ensures an extra layer of security, while its geological stability and location, 130m above sea level, means the vault would be safe even in the worst-case scenario of sea-level rise. The storage facility is buried 150m deep into the side of a mountain where there is no radiation and where humidity levels remain low. The mountain also acts as a natural freezer, reducing the facility’s reliance on mechanical refrigeration. The local infrastructure on Svalbard is also very good despite its remoteness – Svalbard is serviced by regular scheduled flights.
Svalbard itself is also politically very stable and military activity is prohibited in the region under the terms of the Treaty of Svalbard of 1920. The local government is highly competent and Norway has long been recognised as a key country in the international efforts to conserve Plant Genetic Resources for Food and Agriculture (PGRFA). 

Building and running the vault

The Global Seed Vault is built to store up to 4.5 million different varieties of seed. Constructed to be highly functional, the rectangular edifice emerging from the side of the mountain is stark but architecturally beautiful. The structure is energy efficient; insulated by the mountainside, it maintains an ambient temperature of -7°C and therefore only needs a further temperature drop to -18°C to reach the recognised standard temperature for the storage of viable seed. 
The vault was built and paid for by the Norwegian government to provide a service to the world community. The structure took 12 months to build and cost NOK 50 million (approximately £4.6 million). The facility runs as a partnership between the Government of Norway, the Nordic Genetic Resource Centre (NordGen) and the Global Crop Diversity Trust. Operations regarding the vault are administered and controlled by an international advisory council of experts representing the Food and Agriculture Organization of the United Nations (FAO), national gene banks, the Consultative Group on Agricultural Research (CGIAR) and the Governing Body of the International Treaty on Plant Genetic Resources for Food and Agriculture (ITPGRFA). 

Inside the building

Some people are lucky enough to visit the seed vault on the rare occasions that you can gain access inside. I had to see the interior of the facility via a virtual tour. 
The front entrance is understated, although to gain access you have to go through half a dozen locked doors, each requiring a different key. Although, security appears minimal, it’s not. The facility is under constant surveillance by Staatsbygg, the government of Norway’s property manager and developer;  security cameras and sensors are located throughout the building. There is some natural security, of course, as the roaming polar bears outside outnumber the human population of Svalbard. 
From the entrance lobby, a 150m long tunnel extends into the mountain before reaching the three main storage chambers. At the moment, only one storage chamber is in use, in time the others will be filled as more seed varieties are deposited. 
Seed is only deposited three times a year and this is the only time when the vault is opened. 

Making a deposit

The metal shelves inside the Global Seed Vault.
Photo credit: Dag Terje Filip Endresen
[via Flickr CC BY-NC 2.0]
On arrival to Svalbard, seed lots are x-rayed and taken to the vault by NordGen staff members. The seed boxes containing the seed, which have been carefully placed in 3-ply aluminium packages, are then wheeled by trolley to the main storage chamber within the vault. Each package will contain on average 500 seeds. 
The seed lots are placed on simple metal shelving and are assigned bar codes to allow easy retrieval. They are catalogued using an information system called the Seed Portal of The Svalbard Seed Vault. This allows depositors to submit seed inventories and the general public to look at basic information about the seed that is stored within. Storage is free to depositors and they control access to the deposits. It is an International Black Box system, which ensures that only the depositor can access the raw seed and open the boxes. 

The most recent seed deposits

Last year, the first tree seeds were deposited from Norway and Finland. In February, pine and spruce seed was taken to the vault for storage from the Norwegian Forest Seed Center and the Finnish gene reserves forests of Lappträsk and Puolango, and Filpula and Lovisa. This deposit provides a back-up in the event that global climate change, forest management techniques and other factors, such as pests and disease begin to compromise the genetic diversity of these forests. It is a method of conserving the existing genetic resources and enabling long-term monitoring of the genetic variation within these forests, including any changes that occur because of tree breeding. This long-term tree seed project involves the countries of Finland, Denmark, Sweden, Iceland and Norway. 
The last deposit of seed was on 26th May 2016, with deposits from Germany, Thailand, New Zealand and the World Vegetable Center in Taiwan. Germany placed over 6,000 accessions into the vault of a number of different crop varieties, New Zealand deposited a number of varieties of sheep food including rye grass and white clover, Thailand deposited some 20 samples of very special chilli peppers and the World Vegetable Center deposited 1,200 seed lots from a number of different nations. 

Our agricultural future

The importance of this seed vault is apparent; it ensures the survival of the world’s most important crop species. Some seed varieties within the depths of this safe haven can survive for up to 4,000 years. In terms of food security, that is long term planning for human agriculture. 

Helen Roberts is a trained landscape architect with a background in plant sciences. She is a probationary member of the Garden Media Guild and a regular contributor to the University of Bristol Botanic Garden blog.


References:

Doomsday Vault Opened for Syrian Seeds: 
What is NordGen?:
Croptrust: 
Forest seed destined for Svalbard:
Forest tree seeds arrive at Svalbard’s ‘Doomsday vault’:
Arctic seed vault ‘key to future global crops’:
Storing the World’s Seeds in a Frozen Mountainside:
From sheep food to chili peppers – seed deposit at Arctic Vault takes the world one step closer to future food security: 
In the vault: David Osit:
Svaalbard Global Seed Vault:

To grow or not to grow: plant propagation at the Botanic Garden

Posted on by andy.winfield

By Helen Roberts

At the start of December, I met up with Penny Harms, Glasshouse Co-ordinator at the University of Bristol Botanic Garden, to discuss the plants that are propagated at the Garden and how this valuable work is carried out. Over the course of the year, I will be investigating the different forms of propagation techniques used in the Garden to maintain and enhance their existing stock of plants. I will cover briefly how these techniques are carried out (bearing in mind that there are a plethora of books available on plant propagation), but I’ll also examine what is happening at the cellular level and examine the ‘why’ behind certain propagating techniques.

As Penny and I examined some seedling plants, she explained to me why propagation is so important at the Botanic Garden. “If we lose some plants outdoors in a cold wet winter, we have a back up of new plants. Some are not simply insurance plants, but are taken as cuttings as a necessity every year as they survive in our climate as annuals, particularly those plants from the South African collection. Others, such as the Mediterranean plants, do not survive as long here in Bristol as it’s generally much wetter and therefore they need to be replaced fairly frequently. Most plants we take from cuttings are mainly tender perennials and frost tender plants.”

Propagation in the Garden won’t likely restart until the spring depending on weather conditions.

In the glasshouses, Penny showed me many of the plants that have been propagated from cuttings, including some beautiful decorative Aeonium species (commonly known as tree houseleek), as well as Pelargonium (geranium), Clematis, Salvia and Passiflora (passion vines) species. Some plants raised from cuttings  are placed in a unit that is misted with water regularly and the bottom is heated to a temperature of 25°C in order to encourage roots to form. The plants all looked wonderfully healthy, not at all like my puny looking specimens that I had taken cuttings of back in September at home. However, the plants that really caught my eye were some small fern plants potted up, which Penny called “fernlets”.

Ferntastic ferns

Ferns belong to the plant division of pteridophytes (spore-producing vascular plants) and are extremely diverse in habitat, form and reproductive methods. Most ferns grow in moist warm conditions and very few tolerate dry cold places. Although they aren’t flowering plants, the frond shapes and colours can be exquisite. Closer inspection of the undersides of the leaves reveal beautiful patterns of sporangia – the vessels containing the spores.

Fern reproduction 101

Fern lifecycle
Image credit: Carl Axel Magnus Lindman
[CC BY-SA 3.0], via Wikimedia Commons

Like other plants, ferns have alternating haploid (single set of chromosomes) and diploid (two sets of chromosomes – one from each parent) generations; the haploid gametophyte produces the cells for sexual reproduction while the diploid sporophyte produces spores that produce the gametophyte. Unlike flowering plants where the gametophyte is reduced to the pollen and embryo sac, fern gametophytes are free-living. (Although they are admittedly less conspicuous than the sporophyte we generally identify as ferns.)

In brief, the sporophyte produces spores, which are shed and grow into gametophytes (also often called the prothallium). In some species, individual gametophytes will be either male or female, while in others an individual gametophyte will function as both sexes. When the conditions are right, the gametophyte releases mature sperm from the antheridium, which swim to the egg-producing part called the archegonia under the gametophyte’s underside. Fertilisation produces a zygote, which develops into an embryo and eventually outgrows the gametophyte to become the sporophyte.

The plantlet sailboats on the fronds of Woodwardia prolifera.
Photo credit: Andy Winfield.

Like many other plants, ferns can also reproduce asexually through branching of the underground root stem or rhizome. Some species will even produce leaf proliferations known as plantlets or offsets, such as the beautiful Woodwardia prolifera, which comes from Asia and grows in coastal regions. It’s small plantlets (or “sailboats” as Penny calls them) drop off the plant and fall to the ground, securing themselves quickly with their roots.

Fern propagation at the Botanic Garden

Fern spores are carefully collected when the ferns are sporolating by cutting fronds and letting spores fall into paper bags. Spores are only collected when they are ripe; usually the sporangia will swell and will turn brown, black, blue or orange depending on the species.

“As far as when to collect the spores,” said Penny, “it is really a case of watching and waiting. The beautiful orange [sporangia] on the Phlebodium aureum var glaucum go a slightly darker brown when they are ready, which makes it easier to know when to collect. And if you lightly tap the frond over some white paper you can watch to see if the spores are being released.”

The underside of a frond from Phelbodium aureum var. glaucum,
showing the sporangia. Photo: Andy Winfield.

Penny added that she often collects additional spores by simply placing a fern frond onto a tray containing already wetted peat-neutral compost with bark mulch to allow spores to drop onto the substrate. Penny had great success growing new plants from spores harvested from a miniature tree fern species called Blechnum gibbum. This plant was looking in a sorry state before the move to The Holmes at Stoke Bishop and so Penny collected spores just in case it didn’t survive the move. However, research revealed that this fern was behaving like a deciduous plant -it had died back, but wasn’t dead. Thanks to Penny’s careful propagation, the glasshouse now holds a number of specimens from this species – all grown from spores of the original plant.

The tree huggers

Some the glasshouse ferns are also epiphytic and will reproduce effectively from spores. One such example is Stenochlaena tenufolia, a South African fern that will grow up trees. Its climbing rhizome can reach up to 20m in length and 15mm in diameter. As young plants, they start off on the ground, but soon start to ascend trees, trading in their connection with the soil for life in the trees. Often plants don’t produce fertile fronds until the rhizome has climbed sufficiently to expose the apical region of the plant to sufficient light. These ferns are grown both from spores and vegetatively at the Botanic Garden.

The runners

Other species require a different approach. Diplazium proliferum, a fern that is widespread in the tropics and subtropics, produces little rooting plantlets along its fronds that can be developed into new plants. The frond is simply cut and laid onto bark mulch, pegged with wire and then half buried with the substrate.

The chain fern, Woodwardia radicans (from the Macaronesian region but also found on other Mediterranean islands) also produces bulbils but these are usually located at the ends of the fronds as a hard nodule. The roots start to develop in the air but when they touch the ground will root into the substrate and form new plants.

Penny explained, “We got these plants from Tresco where they grow as huge sprawling mounds. The small bulbils eventually form quite large plants, but are still connected to the original. This gives this fern its very relevant name. New plants can simply have the connection cut and be dug up and transplanted elsewhere.”

A brief step-by-step lesson on how to propagate ferns

At the Botanic Garden ferns are being propagated very successfully, but there is no reason why horticulturists at home should not be able to have the same degree of success. Penny offers her expert advice in propagating ferns by spores below:

Ferns can be propagated vegetatively, by division, or similar to sowing seed from flowering plants, by spores, which are found on the underside of the fern fronds. Some fern species are very difficult to propagate from spores, however Adiantum, Pteris and many Blechnum species are reliable.

Here are the main points for the propagation of cool glasshouse ferns from spores:

  1. The spores should be collected when ripe. The sporangia found on the underside of the frond, will (in most cases) change in colour from a light to dark brown to indicate the spores are ripe. To check, lightly tap the frond to see whether the tiny brown spore cases (sori) are released. If so, the fronds can be cut and gently placed into paper bags in order to collect the fine sori ready for sowing (see point 2) or the frond can be cut and placed directly onto the surface of a pre-prepared tray of compost, allowing the spores to fall naturally as the frond dies away. 
  2. Sow the fern spores. Collect the spores from the bottom of the paper bag and sow immediately. Fresh spores will germinate far more successfully than ones that have been kept for some time and dried out. Use clean, shallow, pots and/or trays with drainage holes. Place a fine layer of gravel on the bottom. Add a layer of peat-free, fine grade compost and gently firm down. Stand the pots and/or trays in water to allow the compost to absorb the water. When the compost is wet, lightly and evenly sow the spores over the surface of the compost. The spores are very fine and on no account should they be covered with more compost, as this will prevent them from germinating.
  3. Keep moist. The trays and/or pots should be covered either with a propagator lid or glass and stood in a shallow tray of water. It is important that the compost does not dry out. 
  4. Position in a semi shaded spot ideally at temperature of 16 – 20°C.
  5. Once the spores start to germinate, the young fern plants (prothalli) should become visible within a couple of weeks. Allow the prothalli to establish themselves for a little while before moving on to the next stage, that of pricking out the delicate new plants.

 Moisture is the most important element for the successful propagation of ferns. 

‘Tis the season of seed cleaning

Posted on by andy.winfield
Weeks ago, Nick suggested I come in on a rainy day to the garden as there was lots of seed cleaning going on in the potting shed. Then it didn’t rain for three weeks. Defeated by the glorious Autumn weather we’ve had, I phoned Froggie, and asked whether I could come in to learn about seed washing…yes, that’s right, I said “washing”. I’m such an amateur! However, Froggie was kind and  refrained from laughing at me and just said, “we don’t really wash the seeds unless they have a particularly fleshy covering”.
We arranged a time for me to come in and, as it happened, it was yet another glorious sunny day. While this made for a nice bicycle commute for me, it meant that the volunteer gardeners were all out in the garden so I would be having an individual, hands-on learning experience with respect to seed cleaning.

So many envelopes

As Froggie and I entered the potting shed, she took me immediately over to a bench lined with trays in which rows of envelopes were stacked up. On the outside of each envelope is written the plant’s latin name, the family name, the year the seed was collected, which collection the plant is from, the accession number and a number that corresponds with its numbered listing in the Garden’s Index Seminum. This is a catalogue of the seeds and spores that have been collected in association with the University of Bristol Botanic Garden. This catalogue goes out annually to the Friends of the Garden, other Botanic Gardens and research institutes. Requests can be made for small quantities of seed for the purposes of research, breeding, conservation and education, or by members of the Friends of the Garden (subject to certain conditions).
The Garden likes to keep three years worth of seeds, but obviously different seeds have different storage potential. Some species, such as those in the Apiaceae family, which includes celery and parsnips, are generally only viable for a year, while other seeds have been found in archaeological digs that are estimated to be thousands of years old and have remained viable (see the 2,000 year old Judean date palm as an example).
Separating the seeds of Salvia forsskaolii. 
“We’ll keep back older years from groups such as the cereals, oats and wheat, as well as beans and peas,” said Froggie, “as they will likely remain viable and it’s good to have a reserve.”
Froggie explains that with the Garden’s involvement in the Seeds of Change project, there are even more demands on their seed stores. Though schools and community groups are encouraged to collect their own seed, the Botanic Garden is sending out lots of seed to start the projects off or replenish projects where collection efforts haven’t been successful.
In the little office at the back of the potting shed there are even more trays of seeds. This is where the staff compile all the seeds that go on the Botanic Garden’s annual seed list. Now having a sense of what the end product looks like, I sense that Froggie is about to show me how much work goes into filling each of these envelopes…

Separating the seed from the chaff

Pouring the Salvia seeds into a sieve to get
rid of the chaff.
I’m shown yet more trays of envelopes – but much bigger envelopes this time – many with stems poking out the top. The gardening staff and volunteers have collected the seed heads and placed them in these envelopes ready for cleaning and this is where the work begins. Froggie picks out the first envelope, it’s Salvia forsskaolii, commonly known as Indigo woodland sage.
We sit at the table, each with a white tray nestled within a larger black tray, which I assume is to collect the seeds that catapult out beyond the borders of my white tray. Froggie doles out a few sprigs of dried plant and shows me that the best technique for this particular plant is a simple flick of the seed head to help release the seeds. I flick and my white tray is scattered in small black seeds. Easy.
With the larger unwanted bits removed, we now pour our tray contents into a sieve to clean the seeds of any smaller bits. The clean seed is then poured into a smaller envelope that is placed back into the big envelope with the remaining plant material that is yet to be cleaned. When all the plant material has been worked, Froggie will then process the seed envelope, doing and final quality control check on the seed and making sure all the information is clearly written on the envelope.  
Nigella damascena before we begin to collect the seed.
We wipe down our trays and spray an anti-static spray to ensure there is no contamination as we move on to our next species – Nigella damascena. This too requires a tapping method, though some persistent seeds need to be squeezed out. There are numerous implements on the table for crushing plant material to get at the seed, but Froggies says they try to discourage crushing as much as possible as it makes for a lot of fine chaff that is difficult to separate out later.
As we work, Froggie fields questions from the volunteer gardeners who are looking for equipment or just confirming that what they’re doing is right. As we work, Froggie relays a few stories about misguided efforts of volunteers – stories of pruning gone awry or cutting back incorrect species – she chuckles about it all and has an ‘it all grows back’ sort of attitude about it. I know Froggie no doubt has a million other things she needs to be doing, but she gives me her full attention and focus and makes me feel as though she has all the time in the world for me. She creates a calming atmosphere, which no doubt comes in very handy when coordinating the efforts of so many volunteer gardeners and teaching new skills.
What my tray looks like after I’ve removed the Nigella seeds
from the seed heads. 
There is quite a bit of fine material mixed in with the Nigella seeds and so Froggie introduces me to another technique for separating seed from chaff. She takes some newspaper and folds it in half and pours seed and fine chaff together onto the paper. Then with a motion not dissimilar from a chef tossing almonds in a skillet, she carefully tosses the seeds in the paper. The fine, lightweight chaff moves to the top of the crease in the paper, while the heavier seeds move down. She can then simply give a very gentle blow to get rid of the chaff off the top of the paper. In the end she’s left with just the clean seeds.
We start on the last one – Avena orientalis – a grass. For this seed you hold the spikelet in one hand and flick the seed out. This particular species has a lovely dark seed, so it is very clear when you’ve got it all separated. 
Froggie uses newspaper to separate the lightweight chaff
from the heavier Nigella seeds.
Not all the seed cleaning is this easy. There are dust masks as some can be particularly dusty – but the staff tend to do the really nasty seed cleaning themselves, letting volunteers do the easier ones. If this were a rainy day, there would be volunteers everywhere working on this and having a good old chat.
Looking at the stacks of envelopes, I ask Froggie when seed cleaning needs to be finished.
“We need it all complete by February at the latest,” Froggie replies. “The seed list goes out in February and people will start to put requests in. We also start sowing at the end of February, beginning of March.”

Checking the lists

Cleaned Avena orientalis seeds with the
lighter leftover spikelets in the background.

In many of my excursions to the garden, the staff have introduced me to the many lists that they keep. There is a seed sowing list, a putting the garden to bed list, and now, I have seen the seed collecting list. This is where the staff make notes against each species – for example, if a plant was too small or late to come into flower. These notes are kept year to year and so if a species is less productive in one area of the garden than another or from one year to the next, all of this information is captured.
“The list is never finished,” says Froggie. “I will just update it when something else changes.”
In years where they are unable to collect seed for a particular species, they draw upon their reserves from previous year so that it can remain on the seed list. Annuals tend to be a priority, but also shrubs. The Garden works hard to insure that there is variety on the seed list.
As a member of the Friends of the Garden myself, I now look forward to receiving the seed list next year and I will have a much better appreciation of the work that goes into collecting the seeds for each of the nearly 200 species listed.