Get free plants for next year by saving seed from your favourite annuals and biennials. Some species even save you the trouble by spreading their own seed around.
This spring and summer I have found dill seedlings all over the garden. The quantity of seedlings has defeated the slugs even though dill is normally on my slithery foes’ “must eat” list. That’s especially welcome since dill’s long tap root makes it very tricky to transplant. 
Quite a few species are just as accommodating: calendula, borage, foxgloves, cowslips and musk mallow, Malva moschata, to name a few. This laissez-faire approach only works with plants that won’t germinate over winter, but wait till growing conditions are suitable in spring.
Coriander seed must be collected as it can germinate whenever there’s a touch of warmth, even in November or February. So you need to collect seed once it’s dry and then sow in spring and summer. If you’re exercising a bit of control over where flowers or herbs germinate, collect fully ripened seedheads and simply scatter the seed yourself. This is particularly successful with poppies and foxgloves that have tiny seeds needing light to germinate.

Whether you want to let the plants seed for you or collect and save for next year, don’t deadhead but leave the seed-heads to fully ripen their seed. The larger the seed, the longer this will take: sweet peas and nasturtiums take several weeks but tiny nicotiana will be ready soon. The process will be much quicker during a dry sunny late summer.
When collecting, cut off the seed-heads and upturn over a paper bag, shaking them to release the seeds.

Empty the seed on a tray, picking out all the bits of dry leaves. Then put your trophies in an envelope labelled with species, variety and date. And store seeds in a safe, secure place as they make a welcome snack for others. Last winter, I naively thought a drawer would be safe but was foiled by some wood mice which nipped in and scoffed the lot. Most seeds last for at least two or three years, some much longer, so I was heartbroken to come across heritage peas and Sweet William seed consumed, brassica packs nibbled and spilt in heaps. I even found a stash of broad beans secreted under the pillow of a spare room bed.

Mice and voles can be just as busy in the garden, nibbling through ripening pea pods. And once I could not understand why there were never any ripe black seeds on a Cerinthe major I was planning to harvest. Then I looked under the large leaf of a neighbouring plant and discovered a pile of neatly snipped off navy blue bracts denuded of their seeds – a vole had been at work.


Plant of the week

Salvia nemorosa ‘Ostfriesland’ is a short, bushy salvia growing to 45cm. It bears abundant spikes of violet blue flowers from summer through to mid-autumn that are extremely attractive to insects. It flowers best when grown in well drained soil in full sun. A good candidate for containers, it is supposedly fully hardy but it definitely needs shelter from excessive winter wet and very hard frost.