At this time of year, a lot of plants are producing seeds that can be collected and either sown immediately or stored for sowing next spring. There is great satisfaction in harvesting your own seed and seeing it through to successful germination and ultimately a thriving plant. Saving your own seed is also a very cost effective way to fill up your garden by getting more plants from the ones you already own.

You can save seeds from all kinds of plants. Annuals and biennials are the easiest to collect and the most rewarding as you move from seed to plant very quickly. Some perennial plants aren’t worth gathering seed from because they reproduce much faster by division. Amongst the annuals that I collect seed from are Cerinthe major ‘Purpurascens’ and the poached egg plant, Limnanthes douglasii. I also gather seed from foxgloves and perennials such as angel’s fishing rods, Dierama pulcherrimum, Dictamnus and Baptisia australis which are slow to bulk up for propagation by division but quicker to reproduce in quantity from seed.

Be aware that not all plants grown from seed will look like their parents. Hybrids and named cultivars generally do not produce offspring with the same traits as the parent plant. Usually only species come true from seed but experimenting can be fun and may yield interesting surprises.

Seed is produced by plants in a variety of forms, each requiring different methods for seed collection. Some plants have obvious seedheads which form once flowers fade. Plants like aquilegias produce seed in pods which split open to release the seeds, while poppies produce seeds in capsules with pores through which the seeds can be shaken out like a pepper shaker. Seeds also form within fruits, berries or nutshells or be carried in cones.

How to collect seeds

Most seeds are collected towards the end of the growing season, in mid to late summer or autumn, but seeds are also produced at other times of the year, depending on a plant’s flowering time. Collect seed from strong, healthy-looking, disease-free plants and only when the seed is ripe and fully mature to ensure high viability. This is often indicated by a colour change from green to brown, black or red.

It is important to collect and keep seeds as dry as possible to prevent them developing mildew or mould. Capture the seeds directly from the plant by picking them individually or cutting the seed heads off and placing them upside down into paper bags. Label as you go with the plant name and date of collection.

If the seed is ripe, the seeds will fall off the seed head into the bag. With plants that propel their seeds explosively when touched, carefully put the bag over the seed head before cutting the stem. Some seed heads may need a bit more drying in a warm, dry place until they release the individual 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 to avoid mould developing.

After extracting seeds, clean off any plant debris, bugs and chaff (non-seed material) which could harbour moulds, pests and diseases.

Storing seeds

Some seeds, such as hellebores, foxgloves and poppies, are best sown immediately as their viability reduces with storage. However, for many species, sowing is best delayed until a more suitable time of year and the harvested seed will need to be safely stored until sowing. Brown paper envelopes are best for storing seeds as they exclude light and any remaining moisture within the seeds will be absorbed by the paper.

Make sure to write the plant name and date of collection on the envelope. Certain seeds, such as magnolia, walnut and oak, must not be allowed to dry out as they cannot then take up water necessary for germination. These are best stored in zip lock bags of damp vermiculite or sand.

Seeds need moisture, warmth and light to germinate, so give them the exact opposite, a dry, cool, dark environment, when storing them. Place your seed envelopes into an airtight plastic container, glass jar or tin box to protect from moisture and pests. Add a sachet of silica gel or grains of rice into the container to absorb any excess moisture. Store the container in a refrigerator, if possible, or a cool, dark place where the temperature can be kept between 5°C and 10°C.

I like to organise my seed packets in their storage container by the month in which they should be sown, using card dividers for each month. Instead of a messy jumble, the seed packets are placed behind their monthly card divider.

Seed viability varies for every plant species. For the most part, seeds that you save from your own garden are at their best for the first 1-3 years. To learn more about individual requirements for seeds, you will need to research details in gardening books or online.

Mary Keenan and Ross Doyle run Gash Gardens, Co Laois. See gashgardens.ie

Instead of cutting our wildflower meadow area once a year, should we just let it grow and not cut it at all? – Jack, Co Monaghan

No, management of a wildflower meadow requires cutting it once a year, typically in late summer or autumn. This critical step is taking the cuttings away to prevent nutrients being added back to the soil. By cutting the grass you are mimicking the action of grazing animals that keep grasses from dominating flowering meadows.

If you were to leave it and not cut at all, grasses and other competitive plants would overpower the more delicate wildflowers and reduce the diversity of species. Without removing the clippings, the soil would also become too nitrogen-rich for the continued presence of many meadow flowers.

Take cuttings: Salvias are a large group of plants popular for adding colour to borders in late summer and perfect to take cuttings from. Also osteospermums, penstemons and fuchsias.

Watering: Keep camellias and rhododendrons well watered in dry spells from late summer into autumn.

Sow seeds: Suitable hardy annuals include Ammi majus, Calendula, larkspur, poppies, Nigella, sweet pea and cornflowers or Centaurea cyanus.

Cut back: Lavender once the flowers have faded, making sure not to cut into old wood.