Georgetown Horticultural Society

Georgetown Horticultural Society

Annual Seed Celebration

Wednesday February 20th, 2019

Participants will be able to try their hand at planting some of the seeds they select from the seed exchange.

Please bring in any seeds you’d like to add to the selection we will have.

Save Those Seeds For The Seed Celebration in February!

By Diana Pooke

I started seriously saving seeds many years ago when I took out membership in various organizations that offered Seed Exchanges. At first I was principally interested in obtaining seeds to grow plants that caught my attention and that weren’t available in the average nursery.

Like many others, I got caught up in the adventure of starting plants from seed but soon I began to seriously look at my garden with seed collecting in mind. That is when I found out that seed collecting could be as addictive as seed starting and that there were almost as many intricacies in saving seed as there was in growing from seed.

Pretty soon I could see a ripe seed head at twenty paces!

There are many types of seed heads: berries, capsules, catkins, exploding and catapulting seed heads, nuts, pods and winged seed and they all need somewhat different techniques for collection and preparation. Like most people, I started with the easiest - poppies. These seed capsules are ripe and ready for collecting when the holes open around the top of the “pepper pot”. The seed requires no preparation, no cleaning, just a shake into a paper bag– a piece of cake! Unfortunately, many others need a bit more work to get them ready for the Seed Exchange.


Make sure the seeds are ripe, on average about two months after flowering. Ripeness is often indicated by a colour change from green to brown.

Collect seed on a dry day and label the bag with the name of the plant.

Snip off stalks or capsules and place them upside down in a paper bag and place them in a dry, airy place. If the capsules don’t open voluntarily when dry, gently crush the pods or capsules to release the seeds e.g. verbascum or digitalis seeds.

Collect seed from fleshy fruits and berries by mashing them in a fine sieve and then rinsing away the pulp in cold water. Leave the seed to dry for a few days on paper towels. E.g. arisaema.

Exploding and catapulting seed heads such as geraniums, lupins, violas, euphorbia and gas plants (dictamnous), need constant supervision as they begin to ripen. The trick is to harvest them before they fully ripen and discharge their seeds. Having collected the pods, put them in a paper bag and, most importantly, close the top of the bag. If you don’t you will be down on hands and knees like I was, trying to pick up seeds that have been catapulted all over the kitchen floor.


After extracting the seed, clean off any surrounding chaff. Chaff can harbour moulds, pests and diseases. This can be done with what I call “huff and puff”, blowing the lighter chaff away from the heavier seed. This is quite a messy process and probably best done outdoors when you might find that a light breeze can assist you. Another method is to spread the seed/chaff mixture on a sheet of paper or a plate, which you then gently tip. The causes the heavier seeds to slide away from the surrounding chaff. Sieves of various sizes are also an option, as is a combination of any of these methods. Excellent instructions for seed cleaning can be found on the internet e.g. or the RHS site.

Viability – the likelihood of a seed growing

As the owner of Chiltern Seed Catalogue points out, “You may or may not get a seed to germinate and grow. However, if you don’t plant it you definitely won’t get it to grow!”

Viable seeds are shiny, fat, heavy and tough – regardless of size of the seed. A seedhead, especially of the daisy family, will produce a multitude of what seem to be mature seeds, but only the biggest seeds are potentially viable. I apply the finger nail test. If the seed resists and skitters away when you press a finger nail on it, it is probably viable. If it is soft and flattens easily it probably isn’t. The size of the seed is often a good ‘giveaway’, big ones are better. However, you have to know what size a viable seed should be and here I often reference that has a photographic library of hundreds of seeds at their actual size. This is how I found out that my Acanthus hungaricus seed was severely undersized and probably not viable.

Is there any seed there at all?

Not all the plants in your garden are going to produce seed. Some hybridized plants like Geranium ‘Roxanne’, are sterile and do not produce seed. This is why they flower so prolifically over such a long period of time. I suspect that Salvia ‘Marcus’ may fall in the same category. Very double flowers often do not produce seed because the pollinators can’t find the sexual parts of the plant in among the petals. Last year when we experienced such long lasting drought and high temperatures, a lot of perennials just shut down and went dormant and did not produce much, if any, seed.

Even if the plant produces seed, if isn’t always straightforward to find it. The evening primrose Oenothera triloba forms seed pods, not in or underneath the flower as is most usual, but at the base of the stem at ground level. Some sedges (carex) produce seeds on the ends of long stems which lay along the ground often feet from the original plant. (The New Zealand sedges are particularly prone to using this trick).

Storing Seeds:

Some seeds, especially of the spring-flowering ephemerals like hepatica, trilliums, hellebores etc. Are best sown immediately as their viability lessens with storage.

For most other seeds:

  • Make sure the seeds are clean and dry

  • Place them in a paper or glassine envelopes

  • Label them

  • Put the packets in an air-tight container in a cool dry place until it is time to bring them in to the Seed Celebration in February