Guide to Bulb Planting Depths

Our complete practical guide to planting bulbs at the best depth to get the best flowering display. Plant your bulbs too deep and flowers will bloom late or not at all, plus you’re likely to get more foliage at the expense of the flowers. If planted too shallow, new growth will become exposed too soon, leaving it more vulnerable to damage by cold temperatures. Shallow planted bulbs are also vulnerable to being dug up by squirrels who will feast on their nutritious food stores.

As a rule of thumb, measure the bulbs from the base to the tip and double or triple this measurement to get a rough idea of the planting depth. There are a few exceptions, though, so it’s worth checking the recommended depth for the specific variety you’re looking to grow.

Tulips

• Depth: 18cm or three times their depth
• When: November to December
• Position: Full sun, ideally in a sheltered spot
• Soil: Not too fussy providing it’s well drained and not too acidic

Daffodils

• Depth: 13.5cm or three times their depth
• When: September to November
• Position: Full sun or light shade
• Soil: Moist, well drained

Hyacinths

• Depth: 14cm or twice their depth
• When: September to October
• Position: Full sun
• Soil: Any moist yet well drained soil

Iris

• Depth: 10cm or twice their depth
• When: September to October
• Position: Full sun
• Soil: Well drained, neutral to slightly acidic

Snake’s Head Fritillary, Fritillaria meleagris

• Depth: 9cm or five times their depth
• When: September to October
• Position: Full sun to partial shade – they prefer a cool spot
• Soil: Rich, moist yet well drained

Crown imperials, Fritillaria imperialis

• Depth: 30cm or three time their depth
• When: September to November
• Position: Full sun (plant on their side)
• Soil: Rich, deep, well-drained soil, ideally enhanced with plenty of well rotted organic matter

Ornamental Onions, Allium sphaerocephalon

• Depth: 15cm or three time their depth
• When: September to October
• Position: Full sun
• Soil: Succeed in most well drained, fertile soils

Crocus

• Depth: 10cm or three times their depth
• When: Autumn-flowering crocus: July - August; Spring-flowering Crocus: September - November
• Position: Full sun
• Soil: Unfussy providing it’s well-drained and gritty

Large Globe Alliums

• Depth: 30cm or three time their depth
• When: September to October
• Position: Full sun in a sheltered spot
• Soil: Succeed in most well drained soils

Snowdrops

• Depth: 5cm or twice their depth
• When: September to November
• Position: Dappled shade is preferred
• Soil: Rich, moist yet well drained soil

Bulb Planting Instructions

• When planting bulbs in your garden borders, aim to plant them in groups of at least 6 to provide a better display.
• Dig a hole wide and deep enough for your bulbs.
• Our planting depth diagram will also help you to work out how deep to dig your hole.
• Place the bulbs in the hole with their growing tip facing upwards.
• Space them at least twice the bulb’s own width apart. Replace the soil and gently firm it, avoid doing this with your feet or too much force as this can damage the bulbs.

See our full guide on how to plant bulbs for more details.