Carol Klein on why planting in pots has so much potential, plus her gardening week
Why bother with containers if there’s plenty of garden to plot and plan for? Planting in pots offers unique opportunities to try out ideas and indulge in planting schemes you might not otherwise be able to experiment with. They can be one-off events, designed for a specific season or a particular place. They can be used to emphasise a scheme within the garden or to deliberately contrast, bringing something completely different to the garden party. They may inject vibrant colour where all is green or do the opposite, calmly adding a green oasis where there’s a jumble of colour. You can grow plants that perhaps wouldn’t be happy in your own soil and put your pots and containers exactly where you want them. You can use containers that fit in, singly and big if you want to make an impact, or smaller and grouped together, in which case they can become a moveable feast.
They can be used to grow plants that are wholly ornamental or to grow edibles, or a mix of both. As for the plants, the greatest fun is to be had by growing them yourself. Although it’s getting a bit late to start off some half-hardy subjects, plug plants for many annuals and vegetables are readily available.
Sometimes in some of our biggest pots we’ll combine together cannas, ricinus, dahlias and exotic bulbs such as eucomis, or we might plant an enormous pot with just one plant – or several pots of one plant. We find Cerinthe major ‘Purpurascens’ does much better in containers than in the open ground. Nasturtiums can be added to fill in and balance the arrangement with their striking colours.
When it comes to which containers to use, the bigger the better, the more scope there is and the easier it is to sustain growth and help plants give their all. If you’re using huge containers, they’re going to be heavy, so make sure pots are in the right place. There are a few instances of gardeners actually putting pots on trollies, which gives a whole new meaning to moveable feast (especially if you’re growing edibles!). With our biggest pots we take up about a third of their volume with a layer of broken plastic pots or chunks of polystyrene on top of which goes a sheet of plastic – we use empty compost bags split down the sides. Puncture plenty of holes in it to ensure decent drainage and line the sides of the pot, too, especially if it’s porous, to help water retention. So we’ve saved on the amount of compost needed to fill the pot but still have sufficient body for the plants to thrive. Plants in pots dry out more quickly than those in the ground so make sure containers never dry out and thus have no check to their growth. Use rainwater wherever possible from a water butt or other source. We use our own mix of compost but whatever you use (and it could be a question of whatever you can find) try to ensure it has a high loam content, which will sustain plant growth and retain moisture longer. Plants in pots cannot draw on the nutrient resources they would have in the ground, so feeding is vital. We use an organic seaweedbased liquid feed once a week and always water it on to wet compost so it’s not wasted on evaporation.
‘We find Cerinthe major ‘Purpurascens’ does much better in containers than in the open ground’