The surprising reason your nasturtium is not flowering, according to Monty Don

Nasturtiums will add a burst of cheerful color to any garden. If yours aren't flowering as much as you'd like - if at all - it could be because the conditions are too good.

In the latest episode of Gardeners' World on BBC Two, host Monty Don shared a simple tip for encouraging nasturtiums to flower. While filling four large pots at the center of the Jewel Garden at Longmeadow with various plants, Monty explained that nasturtiums will actually flower best in poor soil.

'We've got extra rich compost, which is ideal for the Ginger lily, and the Bidens will be fine. But nasturtiums flower best in very poor soil,' the gardening expert says.

'If you put them in rich soil, you will have more foliage than flowers.' So, if your nasturtiums look like they're ready to be moved into a bigger pot, you could try adding some grit or sand into your soil mix.

Fertile soil containing a good mix of compost and leaf mould like Monty Don used in his pots, will typically lead to lots of leaves at the expense of flowers. A little like over-watering your best indoor plants, you might be giving them too many nutrients.

But, as Monty Don points out, leafy nasturtiums might not always be a bad thing. 'I rather like the idea of this foliage hanging down over the edge of the pot,' he says. 

'Because the soil is rich it will grow longer. And it will flower, it just won't flower so much,' he says. We also think there's something lovely about the circular leaves, in contrast with lots of angular petals and leaves elsewhere in the garden.

If putting lots of wildlife garden ideas into practice is a priority, it's worth reducing the richness of your nasturtiums' soil. After all, the more lovely flowers you have, the more likely your plot will hum with pollinators.

The specific type Monty Don uses in his pots are Nasturtium 'Tip Top Alaska Deep Orange' with variegated leaves. But, depending on your garden color schemes you could opt for white or red varieties.

Nasturtiums are fairly easy to grow and will do best in full sun. Bees love them, and you can even add them to a summer salad, as they're one of the edible. You can find more edible flowers in our guide.

Monty Don also added Bidens 'Hawaiian Flare Orange Drop' into the pot for their marmalade orange color – these are great for container gardening ideas if your garden gets plenty of sun.

We tend to think most plants need rich, fed soil to do well – but thanks to Monty's tip for nasturtiums, we know that's not always the case.