If you're all set to plant your spring bulbs but you're wondering how deep to plant tulip bulbs, you're not the only one – it's a question that puzzles us all, so we thought we'd do a little research.
Learning how to plant tulips in pots and the ground is fairly simple, but planting them at the right depth is key to successful growth. You'll also need to figure out when to plant tulip bulbs for the best results.
We asked garden experts exactly how deep to plant tulip bulbs to ensure we're getting the springtime favourites off to the best possible start.
What you'll need
This sturdy stainless steel and wood dibber is measured to help you plant your bulbs at the right depth.
There's no need to bend with this long-handled bulb planter – it can remove a 6cm-diameter core of earth, making bulb-planting easy.
This nifty hand tool includes a measured depth guide on the stainless steel side to help you plant your bulbs correctly.
How deep to plant tulip bulbs
One of the most important parts of learning how to plant bulbs is planting them at the right depth. The same applies to tulips, so knowing how deep to plant tulip bulbs is key.
'Ideally, you should plant tulip bulbs at a depth of five to six inches, although they can go slightly deeper in pots,' advises David Glass, head gardener at Bowood House & Gardens.
If you haven't got a measured dibber or a rule to hand, you can use the bulb itself as a guide.
'A general rule of thumb that we suggest is twice the depth of the bulb, planted pointy side up,' says Matthew Johnson, senior gardener at Borde Hill.
Matthew says you shouldn't stress about the orientation of the bulb, though. 'It doesn't matter too much which way you plant bulbs as they will find their way up to the light,' he explains.
But what's the science behind this guidance?
'Tulips like cold conditions, and deeper soil offers consistently low temperatures, allowing the bulbs to thrive,' David explains.
What happens if you don't plant tulip bulbs deep enough?
Now that we've discovered how deep to plant tulip bulbs, we thought we'd dive into the effects of planting them too shallow.
'Planting tulips at a shallow depth can cause several issues,' says David. 'It leaves the plants more exposed to vermin, which are likely to disrupt the bulbs.'
There's also an increased risk of weather damage. 'If tulips are too shallow, they won’t be properly anchored in the ground, leaving them at risk of being rocked by the wind,' David explains.
'Finally, temperatures at a shallow depth of soil are not optimal for tulip growth, which can stunt growth and impact flowering.'
That said, not all shallow tulip bulbs are doomed. 'If they are a little shallow, they may just need some support when it comes to flowering,' says Matthew. 'Some people even grow bulbs in gravel and water, or just water, and they will still flower!'
FAQs
Can you plant tulip bulbs too deep?
We've already established why planting tulip bulbs too shallow can stunt their growth, but can you plant bulbs too deep?
'Yes, to a point,' says head gardener David. 'But you’re better off planting tulips too deep rather than too shallow.'
We also asked David what planting tulips too deep means for the flowers. 'When planted deeper than five to six inches, it may delay flowering,' he says. 'If bulbs are planted as deep as nine inches, it’s possible the tulips won't have enough energy to reach the surface.'
There's also the risk of rotting. 'If you plant your tulip bulbs too deep, the bulbs could start to rot which may delay growth and prevent your beautiful tulips from flowering,' says Morris Hankinson, founder of Hopes Grove Nurseries.
What is the best month to plant tulip bulbs?
Rules around when to plant bulbs for spring vary between varieties, but generally, November is a great time to plant tulip bulbs.
Planting earlier in the autumn can increase the risk of tulip fire disease because temperatures are still relatively warm, so wait until the weather cools right down before you get your bulbs in the soil.
Now you know how deep to plant tulip bulbs, you can get planting and look forward to elegant spring blooms.
