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How to plant bulbs

There are 3 steps for good bulb (or in some cases corm or tuber) planting:

Step 1 – prepare the soil

Bulbs, like any other plants, need to be planted in the optimum soil conditions. So prepare the ground by improving the soil with organic matter such as garden compost and, if drainage is poor, dig in some grit.

When you’re intending to lift and store the bulbs after flowering, you can use containers with mesh sides (the ones used for water plants are ideal) to plant the bulbs in, simply burying the whole container into the soil, then lifting it out when the bulbs are finished. Make sure that you keep the container well watered when it’s out of the soil as the open sides will dry it out very quickly.

If you’re planting them in pots make sure you pick a container which is deep enough and wide enough for the final size of the flowers (particularly if growing tall plants such as lilies) and has drainage holes at the bottom. If the pot is fairly large, add a layer of gravel or similar drainage material into the bottom of the pot. If you’re intending to replace the display each year (or at least remove the bulbs for replanting the next season) then you can use a mix of 75% multi-purpose compost and 25% grit or perlite. If you’re intending to keep the bulbs in the pot for more than a year, replace the multi-purpose compost with a loam-based compost such as John Innes No.2.

Step 2 – plant the bulb

Bulbs that flower in the spring should be planted in the autumn, as should summer-flowering bulbs which are hardy (ie which can survive the winter weather). More tender summer-flowering bulbs can be planted in early spring when the worse of the weather is over. Plant autumn-flowering bulbs in late summer.

If you’re buying new bulbs then plant them as soon as possible.

Check the bulb over before planting it and discard any which are damaged, shrivelled, soft or showing signs of rot.

Bulbs are best planted together in groups and it can take 25 to 50 bulbs to create a really impressive display. If you are short on cash but have a good supply of patience, you can plant bulbs more sparsely then lift and propagate them each year to gradually build up your stock. If you’re naturalising bulbs in a lawn then throw the bulbs over the grass and plant them where they land to get a natural-looking display.

Dig a hole with a trowel or use a specialist bulb planter (if you have lots to do the long handled ones you push in with your foot are easier than the shorter ones). The hole should be as wide as your bulb is. If you’re planting in a lawn you can either dig individual holes, or lift the turf if you’re planting a large number of bulbs in a particular area.

The depth to plant bulbs can be rather confusing, though most packets will include planting depths (so don’t bin them before you’re finished!). Here’s a rough guide to how deep common bulbs should be planted:

  • Allium (most varieties) – 10 to 15cm deep (4 to 6 inches)
  • Amaryllis – growing tip at soil level
  • Bluebells (Hyacinthoides) – 8cm deep (3 inches)
  • Colchicum – 10cm deep (4 inches)
  • Crinum – neck of the bulb just above soil level
  • Crocus – 8 to 12 cm deep (3 to 5 inches)
  • Cyclamen – just below soil level
  • Daffodils (large varieties) (Narcissus) – 20cm deep (8 inches)
  • Daffodils (smaller varieties) (Narcissus) – 15cm deep (6 inches)
  • Dahlia – 15cm deep (6 inches)
  • Fritillaria imperialis – 25 to 30cm deep (10 to 12 inches)
  • Fritillaria meleagris – 8cm deep (3 inches)
  • Galtonia – 15cm deep (6 inches)
  • Gladiolus – 10 to 15cm deep (4 to 6 inches)
  • Hyacinths (Hyacinthus) – 12 to 15cm deep (5 to 6 inches)
  • Iris reticulate – 10 to 15cm deep (4 to 6 inches)
  • Lilies (most varieties) (Lilium) – 2 to 3 times the height of the bulb
  • Muscari – 10cm deep (4 inches)
  • Nerine – nose of the bulb should be above the surface
  • Rain lily (Zephyranthes) – 10cm deep (4 inches)
  • Scilla – 8 to 10cm deep (4 to 5 inches)
  • Snowdrops (Galanthus) – 10cm deep (4 inches)
  • Sparaxis – 10cm deep (4 inches)
  • Tiger flower (Tigridia) – 10 to 13cm deep (4 to 5 inches)
  • Tulips (most varieties) (Tupila) – 15cm deep (6 inches)
  • Winter aconites (Eranthis) – 5cm deep (2 inches)
  • Winter daffodil (Sternbergia) – 20cm deep (8 inches)

Put the bulb in the hole with its nose (the pointy end) upwards, if you can’t tell which end is the nose then plant the bulb on its side, it will turn itself the right way round. Space the bulbs at least double the bulb’s width apart. In pots they can be planted closer, just one bulb’s width apart.

Replace the soil on top of the bulb, breaking up large clumps and gently pushing it down so it doesn’t leave gaps around the bulb. Don’t press too hard or you could damage the growing tip.

If you’re planting in a container then fill the container to the depth you need the bulbs to be at, put the bulbs in, then top up the soil. Cover the top of the container with chicken wire to prevent squirrels, mice or cats digging in it; this can then be removed when the shoots appear.

Mark out the area where the bulbs are planted so you don’t accidentally start digging there later on in the year and disturb or damage the bulbs.

Step 3 – aftercare

Water bulbs in containers regularly in the weeks leading up to them flowering (ie when they are actively growing) and after flowering until the foliage has died down. If you’re leaving the bulbs in the pot while they’re dormant you can reduce the watering, but just make sure the soil doesn’t dry out completely.

Regularly feed the bulbs while they’re growing using a balanced fertiliser like Growmore on beds and a liquid feed (tomato feed is ideal) in pots. Keep on feeding them after flowering until the foliage dies down.

Deadhead spent flowers regularly, but don’t cut down the foliage, leave it to die back naturally – the bulbs need this to continue photosynthesising and build up energy for next year’s flowers.

Whether or not to lift your bulbs once they’ve finished really depends on personal choice. If you’re dealing with tender, summer flowering bulbs then you’ll need to lift them to guarantee that they survive the winter. With most other bulbs you can risk leaving them in the soil, though lifting and storing the bulbs will often give you a better display the following year. Once lifted, allow bulbs to dry out upside down, dust with sulphur if there are any signs of rot, then store them in an open box somewhere cool and dry. Check them regularly and discard any which are rotting.

We also have tips for propagating bulbs and forcing bulbs for Christmas flowers.