How to Collect Seeds

Published on August 11th 2019
The ripe seeds of a foxglove spilling out of a seed head on a wooden bench.
As I write this, the sun is slowly and steadily beating down, and the buzzing insects are flying from flower to flower, busily transferring pollen. The plants are changing their priorities from flower creation to seed production. With the ultimate aim of species survival in mind, they will produce hundreds of seeds in the hope that one will survive to germinate and produce the next generation. And we can get in on the act, collecting seed to grow at home, producing plants relatively cheaply and getting the satisfaction of knowing "we grew that".
A group of Welsh poppy's ripe seed heads in front of a yellow Welsh poppy flower.
Poppy capsules open at the top when the tiny black seeds inside are ripe.
You can collect the seeds from many different plants, but generally, only self-pollinating plants will 'come true' I.e. produce plants that are the same as the parent. Hybrids and plants grown in the open can produce seedlings that have a variety of differences. The seedlings of plants such as aquilegia, hollyhock, foxglove, lupins and opium poppies, when grown in the garden, are unlikely to have the same coloured flowers as their parent. This is because they have likely will have been cross-pollinated from a neighbouring plant.
A ripe seed head on the stem of a Foxglove plant
The lower seed heads of a foxglove flower stem will be the first to ripen and split open.


As a very rough guide, seeds tend to be ripe roughly two months after the flowers appear. But this is very variable, and seed heads can ripen suddenly in hot, dry spells and disperse before you realise. So keep an eye on the ones you want to collect.
Allow seed heads to ripen on the plant; if you collect them while they are immature, the seed will not germinate. As soon as you see seed heads (such as capsules and pods) change colour to brown, black or red, you can collect them.
Tip: Have envelopes and a pencil handy when you're out and about in the garden during summer.
Another key ripe seen indicator is the activity of the local bird population. When you see them raiding the fruit from bushes, it's time to collect berries.
Squirrels will also let you know when the nuts are ready to be collected. I only managed to harvest a few of the hazelnuts from my allotment tree before they stripped it!
A close up of a Lupin's seed head
The ripening pods of lupins will change to brown and black when they're ready to be collected.


Collect seed heads on a dry day and pop the heads upside down into an envelope or paper bag, remembering to write the plants name.
Seed heads that haven't opened yet can be placed on a warm windowsill, or greenhouse bench, to finish the drying process. Drying will make it much easier to get the seeds out, especially from pine cones. If some still haven't opened after drying, gentle squeezing or crushing should be enough to release the final few.
Berries and fleshy fruits such as strawberries and tomatoes need to be mashed through a fine sieve. Before being sown or stored, the pulp needs to be rinsed off with cold water, and the seeds spread on paper towels to dry for a couple of days.
Once seeds have dried, clean away any remaining material (also known as 'chaff' from the seed case. Removal can help to reduce the possibility of moulds, diseases and pests from being stored and ruining any future sowing.
A close up a Chive seed head opening up to reveal the ripe black seeds inside
Chive seeds are easy to collect and sow. In fact, they even happily self-seed across my allotment without my help


Some seeds don't store well, and their viability reduces over time. These will need to be sown straight away. However, the majority of seeds are best stored and planted at the right time (autumn or spring).
Making sure your seeds survive and don't rot from fungal disease or desiccate to dried out husks only requires a few simple steps.
Use paper envelopes and label them clearly. I know I've mentioned this several times, but accurate labelling will make a huge difference. There have been several times I've said to myself that I'll do it later, only to discover the packet two months later with no recollection of what they are. Very few seeds are as easy to identify as French marigolds or Nasturtiums.
A French marigold seed head
The seeds of the French marigold are very distinctive.
Place these packets in an airtight container; those plastic containers from takeaways are useful for this. Keep the seeds at 5C (41F) by placing them at the back of the fridge until you're ready to get sowing.
If you have any packets of silica gel (perhaps from the packaging of any recently bought tech), pop one in with the seeds, this will help to remove any excess moisture in the tub. DIY stores sell moisture absorber granules (for dehumidifiers) which will also work.
Some seeds will need to be stored in a way that stops them drying out. These can be popped into a plastic bag with damp vermiculite and kept for several months. You can also use sand, or a mix of coir and sand depending on which is easiest for you. Oak and magnolia seeds need to be treated this way.
If you're unsure how to store a particular seed, a quick online search should give you the answer.
A plastic see through storage box full of seed packets
If you've collected more seeds then you could possibly sow, you could offer them to friends and family or take along to seed swap events.
I have to admit I don't collect and store that many seeds, but this year I'm planning to collect onion seeds. This is only because I forgot to harvest part of last year's crop and upon re-discovering them this spring, have decided to let them grow and go to seed. I'll let you know if I get them to germinate next spring!
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