4 March 2020

Watching seeds grow is nothing short of a miracle. So how do you ensure they have the best chance of survival?

There’s much to consider: when to plant seeds, where to plant them, and how to move them.

(Photo By Enrico Sacchetti/millennium images, uk)

A former gardening colleague used to say that sowing seeds and watching them grow into full-sized plants within a matter of weeks was as close as most people ever come to seeing a miracle. That notion unavoidably comes to mind at this time every year, as I open my seed packets for the coming season. And the smaller the seeds, the greater the miracle appears to be. For though it is understandable that seeds as big as those of peas or runner beans will end up as plants, the dust-like ones produced by species such as lobelia do appear to be in need of some divine intervention.

It also struck me this year how the storage and packaging of seeds has improved – most are now in foil-lined packets, not just paper. The rule was once the larger the seeds, the shorter the time they would remain viable. Peas and beans, for example, would be of use for only one year after being packaged, even if stored in a fridge, while tiny onion seeds could last almost forever.

But thanks to improved packaging, I now see some really large seeds being dated for sowing as far ahead as the end of 2022. There is no need to discard part-used packets at the end of every season, especially if you keep them in a fridge.

For many gardeners, however, the seed packets can themselves present a conundrum. The sowing information on the back – often displayed in the form of a coloured calendar – commonly gives two options: the months for inside sowing and those for doing so outside. Which should you choose?

Logically the inside option appears better because in the protected environment of a greenhouse, conservatory or windowsill, free from the vagaries of the weather and the depredations of slugs and other pests, fragile young seedlings must be more likely to survive. And this is indeed true of half-hardy and tender plants that cannot be risked outside before mid-May.

But raising any seedlings inside means they must at some stage be hardened to external conditions using a sort of halfway house, such as a cold frame, before being planted outside – and some plants just do not respond well to being disturbed. I find most of the pea and bean family is more likely to survive when sown directly outside, despite their possible vulnerability to pests. Even if I have to re-sow some of the plants, the long-term success of the crop is still better than when they are transplanted. Root vegetables – parsnips, carrots, beetroot – should also be sown directly in their growing positions and thinned out in due course.

Brassicas – cabbages, cauliflowers and their relatives – are probably the most robust of all garden vegetables and may be sown directly in their growing positions, raised inside or sown in a transplant bed from which they can later be moved into their final positions. They will tolerate any number of moves and any amount of ill-treatment.

Hence there is neither one rule for everything, nor one plan to fit all. In one important bed in my garden, about half the subjects – including dahlias, asters and antirrhinums – are transplanted while the rest – cornflowers, cosmos and scabious among them – are direct sown. This is our cutting bed, in which flowers are grown to be picked, which lies alongside the vegetables in the kitchen garden. Thankfully, its existence means our permanent ornamental display beds do not have to be mutilated in the cause of decorating the house.

Next week: Nina Caplan on drink