As we edge towards the end of the growing season, many plants are slowing down and reaching the end of their lifecycle. Both annuals and perennials produce an abundance of seed during this time, and there's often more than enough for you to collect, save, and grow free plants next year.

Collecting seeds and growing your own plants is not only highly satisfying and cost-effective, but it can also help you reduce any associated packaging waste and emissions when buying seed. You can stock up on paper envelopes from Amazon to store them correctly over winter until it's time to plant in spring. These are also great for gifting to family and friends to start their own garden.

Here, our experts share their tips for harvesting popular seeds in August and how to safely store them.

1. Cosmos

Easy to grow and hugely popular, cosmos are perfect for brightening up a border or adding to a container. With cosmos varieties available in soft pastel shades and vibrant hues, these annual flowers are a versatile and dependable favorite.

As with the others mentioned, waiting until the morning dew has dried or after a few rain-free days will help ensure those you collect are dry. Collect the seed heads by snipping them off with some precision snips, such as these Felco F322 pruning snips, available from Amazon, when they are brown and dry to the touch.

Leave the seedheads to dry further on a sunny windowsill or in a greenhouse on paper towel before storing them somewhere cool, dry, and dark over the winter.

Mintee Kalra, Founder of Mintee Kalra Studio, also suggests: 'Don't collect seed from every flower. Be selective. Save seed from the healthiest, longest-blooming plants with the strongest form. You're quietly shaping the future of your garden.'

2. Calendula

Blooming from spring until the fall, calendulas are ideal not only for your garden but, being edible flowers, are perfect to jazz up a salad with. Additionally, Calendula officinalis is an excellent companion plant for your beans and tomatoes.

To collect calendula seeds in August, leave some flowers to fade and form seedheads. Once the petals have dropped and the seedheads turned from green to gray-brown, snip them off. However, to reduce any chances of mold, Mintee advises, 'Harvest only once the seed heads have fully matured and dried on the plant.'

Once completely dry, you can gently separate the curved seeds for storage.

When it comes to choosing storage vessels, Amy Martin, landscape designer and the founder of Plant and Bloom Design Studio, advises, 'storing them in a breathable container, never plastic. Small paper envelopes are my favorite; they label easily and stack neatly until it's time to sow next season.'

Once placed in a labeled envelope, you can organize them in a box, such as this Pethiy moisture-proof seed storage box, available to purchase from Walmart.

3. Zinnia

Another flower seed to collect in August is zinnia. Adored for their pops of subtle or vivid color and enticing shapes and sizes, zinnia varieties are wide-ranging.

To keep these annuals flowering as long as possible, regular deadheading is required. However, to allow the seedheads to form and dry out before winter arrives, you may want to leave some blooms to go to seed in late summer.

In warmer parts, zinnias can self-seed, but to make sure you have a free supply of zinnia plants next year, you need to collect some as well.

To harvest zinnia seeds, once the petals are long gone and the seedheads are dry and crispy, remove the entire seedhead and separate the arrow-shaped seeds to store.

To ensure high germination rates, Mintee suggests, ‘Store seeds somewhere cool, dry, and dark in paper envelopes or packets, which allow any remaining moisture to dissipate. Heat, humidity, and light are the quickest ways to reduce seed viability.’

If you have never collected flower seeds before, a seed-collecting kit that provides everything you need to harvest and store seeds can be a great place to start. Orionstar seed storage organizer kit, is available to purchase from Amazon.

4. Sunflowers

Grown to brighten up the garden and as a cut flower, sunflowers (Helianthus annuus) are not only easy to grow but easy to collect seed from.

Depending on the sunflower variety and time of sowing, sunflowers may not be ready to harvest their seed from until early fall. However, earlier varieties, especially when grown in hot, dry areas, may well be ready for collection.

As an important food source, you will want to leave some seeds for the birds, but sunflowers can produce hundreds of seeds, so there are enough to go around.

To collect sunflower seeds, cut off the brown, dry, faded flower head and place it on a tray or sheet. Rub and, if necessary, gently pull away the seeds. To ensure they are free of moisture, place the seeds on a paper towel for 2-3 days before placing them in an envelope.

Labeling your seed envelopes is essential for clear organization. But Mintee further recommends, 'Label more than just the plant name. I like to include the collection date and one observation about the parent plant: 'longest flowering,' 'best color,' or 'most vigorous.' Over time, those notes become a quiet record of the garden you're cultivating.'

5. Nigella

Prized for its delicate and whimsical flowers, nigella, or Love-in-a-Mist as it is affectionately known, is one to sow in the fall and is a lot tougher and hardier than it looks. Additionally, as a self-seeding annual, it tends to naturally come back year after year.

Once its intricate blooms fade, nigella develops balloon-like seed pods that turn brown and rattle when they are ready to be collected.

To avoid losing the tiny seeds, cut off a stem holding several seed pods with a pair of pruners, such as these Okatsune 103 bypass pruners available from Amazon, and place them in a paper bag upside down. Shake gently and the seeds will fall out of the pods and collect at the bottom of the bag.

6. Sweet Pea

One of my favorite flower seeds to collect in August is the sweet pea ( ). A stalwart of cottage gardens and cut flower gardens, their beautiful and scented flowers are equally at home scrambling up an obelisk as they are in a vase indoors.

Producing a profusion of flowers over the summer, you will want to deadhead sweet peas regularly to stop them setting seed. However, come late summer when they begin to wind down, you can let some flowers form pods so you can collect sweet pea seeds for next year.

Once the seed pods are brown and brittle, you can cut them off and bring them inside to dry out further. After they have completely dried, you can collect the round, black seed by splitting the pods open and storing them in a glass jar.

Whether you gift the seeds to a friend or sow them and pass young plants on to a neighbor, sweet peas are always gratefully received.

Airtight glass jars are available to purchase from Walmart.

What to Shop

Having collected your flower seeds this August, you may be wondering how long you can store the seeds for. The answer depends on the type, as some seeds should be sown within a year, and others seem to last indefinitely. However, annual flower seeds tend to remain viable for 1-2 years before their germination rates begin to decrease. But there are exceptions, and if stored correctly, they can last longer.

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