How do I layer bulbs in a pot to flower three times?

A bulb lasagne packs three flowering seasons into one container by exploiting the fact that different bulbs want different depths anyway. It looks like a trick and it is really just efficient use of a pot. The one thing people worry about — the deep bulbs being blocked by the ones above — does not happen: shoots simply grow round them.

What you'll need

• A large pot, at least 350mm across and 350mm deep
• Peat-free multipurpose or bulb compost
• Horticultural grit for drainage and top-dressing (optional)
• Bulbs in three sizes and flowering times
• Pot feet
• Slow-release fertiliser (optional)

Step by step

1. Choose a big enough pot.At least 350mm across and deep, and bigger is better. A small pot cannot fit three layers at sensible depths and will freeze and dry out faster. Make sure it has drainage holes.
2. Choose the bulbs by flowering time, not just by size.The point is succession. A typical combination is late tulips deepest, hyacinths or mid-season narcissi in the middle, and crocus, muscari or iris reticulata on top, giving flowers from late winter into May.
3. Fill the base with compost to the depth of the first layer.Add grit to the compost if the pot will stand outdoors all winter — perhaps one part grit to four of compost. The deepest bulbs sit roughly two thirds of the way down the pot.
4. Set the largest, latest bulbs close together but not touching.A few millimetres apart, pointed end up. Keep them off the sides of the pot, where the compost freezes hardest and dries fastest.
5. Cover with compost and add the middle layer, offset.Enough compost to bury the first layer completely, then set the medium bulbs deliberately in the gaps between the ones below rather than directly on top of them. It is not essential — shoots grow round obstacles — but it gives a better result.
6. Cover again and add the top layer of small early bulbs.Just below the surface, at the shallow depth they want anyway. These flower first, in late winter.
7. Leave a watering gap and top-dress with grit.Finish the compost a finger's width below the rim so the pot can actually be watered. A layer of grit on top keeps the compost surface open, deters squirrels a little and looks better.
8. Stand it on pot feet in a sheltered spot.Winter wet is what rots bulbs in containers, not cold. Raising the pot so it drains freely is the single most useful thing you can do for it.
9. Water sparingly over winter and more as growth starts.Damp, not wet, through the winter. Once shoots appear, keep it evenly moist. A pot under the eaves of a house may need watering even in January.
10. Decide afterwards whether to keep it.Deadhead as each layer finishes and feed with a high-potash liquid while the leaves are green. The small bulbs and daffodils are usually worth planting out in the garden afterwards; the tulips often are not, and many people replant a fresh pot each autumn.

Tips

• Three layers is the practical maximum in a normal pot. Four sounds better and produces a crowded pot with poor flowering.
• Choosing all one colour across the three layers, or a deliberate progression, looks far better than a mixture of everything.
• Squirrels dig newly planted bulb pots enthusiastically. A layer of chicken wire over the compost until the shoots appear, hidden under the grit, stops them.
• Pots planted in September and October have the longest rooting period. A lasagne planted in November still works, and tulips prefer it.

Common mistakes

• Using a pot that is too small or too shallow — There is not enough depth for three layers, the compost freezes through, and the display is thin.
• Packing the bulbs so they touch — Touching bulbs rot into one another. A few millimetres of compost between them is enough.
• Standing the pot flat on a hard surface all winter — It cannot drain, the compost stays saturated and the bulbs rot. Pot feet solve it.
• Filling the pot to the brim — There is nowhere for water to sit while it soaks in, so most of it runs off the surface.

Questions people ask