If your garden has been bursting with colour this summer, don't be too quick to tidy everything away. While deadheading encourages many flowers to keep blooming, leaving a handful of your healthiest plants to set seed can reward you with a free supply of flowers for next year.
Collecting seeds is one of the simplest and most satisfying gardening jobs, helping you save money while growing plants that are already well adapted to your garden's unique conditions.
From cheerful cosmos and vibrant calendula to striking sunflowers, many popular flowers produce seeds that are incredibly easy to harvest and store. With just a little patience and the right timing, you can gather seeds that will germinate into strong, resilient plants next spring. The key is knowing when seed heads are ready, how to dry and store them properly, and the best way to sow them for reliable results.
Below are the easiest flowers to collect seeds from, along with top tips for harvesting, storing and successfully growing your own blooms year after year.
The easiest flowers to collect seeds from
"If there’s one job I never rush at the end of summer, it’s deadheading," says Andrew Jackson, an award-winning garden writer, designer and creator of The New Build Manifesto. "I always leave a few of my best-performing plants to mature naturally because they’re effectively producing next year’s garden for free."
Andrew recommends annuals such as:
- cosmos
- calendula
- nigella
- cornflower
- poppies
- foxgloves
- sunflowers
"In my garden I make a point of collecting seed from the plants that have genuinely thrived in my conditions" states Andrew.
"If a cosmos has flowered continuously despite the exposed position, or a calendula has coped with poorer soil, I want more of those genetics in the garden next year."
Ela Naylor, plant care expert at Envii, explains "Harvesting sunflower seeds is extremely beneficial as the seeds contain calcium, phosphorus, and potassium."
In addition they work well in recipes or as a healthy snack.
How to harvest your own flower seeds
It's important to be patient, the seed heads should be browning and completely dry before you collect them. Harvesting too early can prevent the seed from maturing.
"I usually choose a dry afternoon and simply snip whole seed heads into a paper bag or envelope. Paper is much better than plastic because it allows any remaining moisture to escape rather than encouraging mould" explains Andrew.
Labelling your seed packets can prevent a mix up as, by October, seeds can look remarkably similar and it can be hard to recall which is which.
For sunflower seeds, Ela recommends leaving the seeds to dry on the plant until the petals become dry and fall off. This occurs in late summer or early autumn, about 30-40 days after the flowers bloom.
Be aware that wildlife will also want to harvest the seeds – but you can net the flower head so wildlife won’t be able to access the seeds, should you wish. Or you can remove the head and leave it in a warm, dry place for the plant to dry out.
Simple ways to store seeds successfully
It's essential that you avoid moisture, warmth and light when storing your seeds. Andrew places a small silica gel sachet within the envelope then places it somewhere cool, dry and dark until spring.
He also notes: "Most flower seed remains viable for several years, but I always sow the freshest seed first as germination tends to be strongest."
How to sow seeds next year
Each plant is slightly different, but most hardy annuals are uncomplicated. You can either sow them directly where you would like them to flower in spring or start a few in modules if I want a more control.
Try not to bury the seed too deeply. "Many flower seeds need only the lightest covering of compost" explains Andrew. "Keep the compost lightly moist rather than wet, and don’t be tempted to overwater."
Harvested seeds often produce slightly tougher, more resilient plants because they’ve come from flowers that have already thrived in your garden.
For sunflower seeds, sowing between April-May is best – and if you are wanting consistent blooms through summer and early autumn, it is best to sow them every two weeks.
Ela advises how to sow your seeds:
- Fill a small pot with peat-free compost leaving ½ an inch of room at the top.
- Place 2 seeds in a pot for insurance in case 1 fails to germinate. Or you can sow individual seeds into toilet rolls, similarly to sweet peas.
- Cover with ½ an inch of compost.
- Water the compost through.
- Place in a plastic bag or propagator on a warm windowsill or greenhouse to ensure germination.
- Plant out when all risk of frost has passed.
Secateurs edit
