Collecting seeds: the theory

Collecting Seeds: The Theory

Collecting your own seed can be really easy and rewarding. In this lesson, we'll explore which types of plants are likely to produce best results, and what 'coming true from seed' means.

Collecting seed from the plants you've grown gives you free seed to sow the following year and allows you to share with friends.

Even for plants that willingly self-seed, you might want to raise some plants undercover so that you can plant them elsewhere in the garden.

When to Collect Seed

• I start collecting in July for the early-flowering plants such as foxgloves.
• By mid-September, a lot of the plants I've grown are going to seed.
• It's all about watching what's going on and finding the optimum time to get the seed.

There's nothing more satisfying than collecting seed from a plant you've sown from seed, and completing that circle.

Which Plants to Collect Seed From

The lifecycle of a plant is that it germinates, grows, flowers, is pollinated by bees or other pollinators, and sets seed after pollination if it's a fertile plant.

• Some flowers aren't fertile, such as if they're sterile hybrids - meaning they won't set seed.

You'll often hear the expression 'coming true from seed'. This means the seedlings produced by you collecting and re-sowing the seed, or the plant self-seeding, grow up to look the same as the parent plant.

• Plants that are straight species – the name is just the botanical name, with no cultivar name after it, e.g. Orlaya grandiflora or Ammi majus – are much more likely to come true.
• Cultivars, i.e. named forms of a plant, such as Calendula 'Touch of Red Buff', may not come true, and sometimes revert to their natural state.
• E.g. poppy 'Amazing Grey' might revert to the wild field poppy Papaver rhoeas.
• You never quite know what you're going to get when collecting seed from cultivars, so it's safer to focus on collecting from species unless you're excited by the lottery of not quite knowing what you're going to get (which I am).

Dahlias – Genetics and Experimenting

Dahlias are probably the ultimate complex plant. They have eight sets of chromosomes while many plants have two, so they're really diverse, which is why we have so many colours and forms.

Different forms become cross-pollinated in the garden, giving weird and wonderful new forms. Dahlias that grow from collected seed will always be variable – even the 200-300 seeds within a single flowerhead.

I'm going to experiment with this and collect seed from my seed-grown dahlias to grow in a special patch next year. If any have particularly beautiful flowers, I'll keep those and dig up the tubers.