Seeds of Change: Growing a Living History of Bristol

SEEDS OF CHANGE: GROWING A LIVING HISTORY OF BRISTOL

Seed Collection and Storage Advice

At the University of Bristol Botanic Garden we collect seed every year from annual plants (plants that complete their life cycle in one year). The seed germinates in spring and grows into a plant which flowers, and then the flowers turn into seeds before dropping of the plant as it dies. The seeds then lie dormant (asleep) in the soil, throughout the winter, waiting until the growing conditions are favourable in the following spring before they wake up and germinate and start the cycle again.

To make sure we get a good display of these plants each year we collect as many of the seeds as we can before they fall to the ground. This is how we do this:

1. Collect seeds on a dry day - if necessary wait until later in the day when the morning is wet/dewy. The seeds must be dry when collected or they could go mouldy in storage. 2. Check that the seeds are ready to collect. They generally change from green in colour to beige, brown or black when they are ripe. Some seeds can be collected all at the same time whilst others may need collecting regularly over several weeks. 3. Collect into trays or paper bags large enough to hold the seeds and most importantly make sure you label the tray/bag with the name of the plant and year. 4. You do not need to collect the whole plant, the seeds may rub off individually into your hands or collecting the seedpod (part containing the seeds) is sufficient.

5. If you are not quite sure that the seed is dry enough to store then leave in trays out of direct sunlight to dry. Turn daily with hands if there is a lot of plant material in the tray. 6. Before storing the seed it needs to be cleaned. Use clean trays to tip the seed you have collected into and spread out to remove as much as possible of any other plant debris and soil that may be in there. Use your fingers or tweezers and even pencils are quite good to push debris to one side. 7. Pop/crush the seed pods if required and then turn them upside down to shake out the seeds. Sieving the seed can help to remove debris. Put into paper bags or envelopes labelled with name of the seeds and year. 8. Wipe the cleaning tray after cleaning each type of seed to avoid contamination with other seed types. 9. Store in a fridge in a sealed plastic tub with some silica crystals to absorb extra moisture. Or in a room which is not too hot and dry (the seeds may dry out too much and die) or too cold and damp (the seeds will go mouldy and die) and out of direct sunlight. Check monthly and discard and seeds showing signs of mould. 10. Wait until spring and conditions are good to sow seed.

Collecting this way can be applied to many other plants you may wish to collect seed from and grow again. For those wishing to know more about what to collect, the following information is for those plant species used in the Seeds of Change project.

Nigella damascena- Collect the pods as the turn brown (leave a bit of stalk to enable the pods to be tipped upside down more easily to shed seeds), the seeds inside will be black and the pods will naturally start to split when ripe.

Setaria viridis- Collect the seeds as they start to turn beige colour. Rub fingers along flower spike and seed will drop off into tray below if ripe, they may start to do this before they change colour. This lets you collect seed but leave the plant still intact to look at. Otherwise wait until all seeds ripe and then cut off entire flower spike and clean later.

Amaranthus caudatus- Collect the seeds as they start to turn a beige colour. Rub fingers along the tassel flower spike to release seed into a tray below and still leave tassel in place to look at. Or wait until majority ripe on plant then cut off flower spikes and clean later.

Calendula officinalis –Seeds start to turn beige and brown and just by rubbing your fingers over them they should easily full of into your hand. If they do not drop off easily then they are not ready and wait a bit longer.

Avena sativa –The seeds will turn a beige colour and can be easily popped out with fingers to leave the papery like covers intact on the plant. If you do not want to leave the papery covers for continued interest then drag your hand up the flower spike to remove all the seeds in their papery covers and pop out later when you clean the seed.

Verbascum sp. –When the seed pods turn have turned brown and start to crack open carefully cut off the entire flower spike (cut down in sections from top) and tip carefully into a bag/tray as there are millions of tiny greyish black seeds in one spike. Do this now rather than clean later as the old hairs on the spike break off easily and are quite dusty.

Eruca sativa –When the seed pods have turned a beige colour they will start to split and release the greyish black ball shaped seed. Collect just the pods and they can be crushed lightly with a pestle or something to release the seed. Sieve to remove debris

Linum usitatissimum – The seed pods will turn a brown colour and pull off the pods and rub between fingers to release the brown seeds. The pod debris tends to end up with the seeds. The seeds are heavier and by tipping onto a several sheets of paper with a crease down the middle, holding the paper either side in front of yourself and then using a rolling flicking motion with both hands the seed will stay in the centre of the paper in the crease whilst the debris (chaff) will work its way forward to the edge of the paper and can be scraped away. Start with a small amount until the mastering the flicking motion and then carry out in small batches.

Papaver rhoeas -Collect seed pods of poppies when they turn brown and you can see a ring of pores just opening under the top of the pod. Cut off with a short piece of stem and hold upright until you can tip into a tray or paper bag the tiny black seeds.