6 Tulip Bulbs per 25-Centimetre Pot Layered in a Sarah Raven Lasagne Planting

Layered bulb planting works by giving each bulb its own horizontal level. In a 25cm diameter pot, the surface area is roughly 490 square centimetres, enough for six standard tulip bulbs of 12cm circumference grade when each sits about 5cm from its neighbours. Three to four centimetres of compost between tiers gives the shoots room to thread upward. Sarah Raven popularised this lasagne approach through Perch Hill nursery, and the mechanics are simple: a tulip shoot bends around an obstruction above it, then continues toward the light.

The planting order puts the largest, latest bulbs at the bottom. Tulips sit deepest, at about 18cm. Narcissi sit around 12cm. Small bulbs or corms, such as Crocus tommasinianus, go near 6cm. Flowering then arrives in reverse order. Crocus opens first, often in late February or March, while tulips are still below the surface. The tulips complete the display weeks later, which is why one container can earn its place on a small balcony from March into May.

Drainage before compost choice

Good drainage is the single thing most likely to make or break a layered pot. A 25cm pot with a single central hole can keep a saturated zone at the base after heavy rain, and a tulip bulb left in that zone for a week can turn to mush. Bulbs will fail from sitting in water long before they ever run short of nutrients. A 3-4cm layer of broken terracotta or coarse gravel lifts the lowest bulbs above that sump.

Some growers leave out crocks and improve the container itself. In a plastic pot, a cordless drill with a 10mm masonry bit can add four side-drainage points near the base in under a minute. Those side holes move excess water out before it lingers around the deepest tier.

A loam-based mix such as John Innes No. 2 gives the pot weight and structure. Compared with a peat-free multipurpose compost, it holds together better through a wet winter and is less prone to collapsing into airless sludge. Mixing roughly one part horticultural grit with three parts John Innes opens the texture further.

That extra weight helps on an exposed balcony. A tall tulip pot in April catches wind hard, and a light peat-based fill can tip over. The mineral mix makes the container steadier as the stems lengthen.

The same drainage rule applies to lily bulbs, which many people add to layered pots for June colour. Lilies dislike wet crowns even more than tulips. Planting a lily bulb on its side, with grit packed around it, lets meltwater drain away from the scales that would otherwise soften and become infected.

The autumn planting sequence

Plant in October or early November, after the soil has cooled and before hard frost locks the compost. Start with the crocked pot and add about 8cm of the John Innes and grit mix.

Set the tulip bulbs on that surface with their noses up. Keep them spaced so they do not touch; six fit across the 25cm circle with room to spare. Cover them with 4cm of compost, firming gently around the bases to remove air pockets.

Place the narcissi on the next tier, offset into the gaps between the tulips below. A lower shoot pushing upward should have a clear path past the bulb above. Add another 4cm of compost.

Scatter the crocus corms across the top layer fairly densely, since they are small and cheap. Finish with 5cm of compost, leaving the surface within 2cm of the rim.

Water once, thoroughly, after planting. Autumn and winter rain usually supply enough moisture. During dormancy, excess water is the usual failure point, while a pot under the eaves often stays at the drier end, which is useful until shoots appear in February.

Feeding is a small job

A tulip bulb already contains the flower for the coming spring. Compost supports the foliage and helps build the following year’s bulb, so heavy autumn feeding achieves little. A single application of balanced liquid feed as the leaves emerge in spring covers the needs of the layered display.

Watering after the shoots are up

By late March, a 25cm container can be packed with roots and leaves. A warm week on a south-facing balcony may dry the compost in two days, especially once tulip foliage is drawing water hard.

Self-watering balcony pots help smooth those swings. A double-walled planter with a 3-4 litre reservoir draws moisture up through a wick or capillary column, keeping the compost evenly damp instead of alternating between saturated and bone dry. In a layered bulb pot, the wet end of the wick belongs in the drainage layer and should be kept clear of the tulip depth, so the lowest bulbs are never held in permanent moisture.

Several pots are easier to manage with a drip timer. A basic Hozelock setup uses the tap-mounted timer, a length of 13mm supply hose and 4mm micro-tubing tapped off to a drip stake in each pot.

Set the timer for a short early-morning burst of five to eight minutes, then check the runoff after the first cycle. If water sheets straight from the base, the burst is too long or the compost has compacted. If nothing emerges after ten minutes, the emitters are clogged and need flushing.

Splitting the day into two short cycles tends to serve a packed pot better than a single long soak. One pass barely wets the top before it drains through, so a second run a while later is what actually carries water down through the compost column to the deepest bulbs.

Where you set the pot changes everything about how fast it dries. A pot tucked in the lee of a wall bakes and holds heat, while a pot on an open rail meets wind that can triple evaporation. The Royal Horticultural Society notes that container plants in exposed positions can need watering far more often than the same plant in open ground, and a tall spring pot is among the more exposed container arrangements. Grouping pots raises the humidity between them and slows drying, which costs nothing before any irrigation kit is added.

After May

Once the tulips finish flowering, leave the foliage to yellow for roughly six weeks so the bulbs can recharge. Pulling the leaves early cuts off the energy transfer back into the bulb.

Layered tulips rarely repeat well in pots. The same crowding that gives the display its density also exhausts the bulbs, so most growers lift the tulip layer and treat it as annual. The narcissi and crocus underneath are more reliable. They can stay in place, or the pot can be tipped out and the bulbs dried for reuse.

A blueberry in the same 25cm container has different requirements. It wants ericaceous compost at about pH 4.5 to 5.5 and an ericaceous feed through the growing season, because it cannot pull iron from the near-neutral John Innes mix that suited the bulbs. Changing the pot from spring bulbs to blueberry means emptying the old mix and refilling from scratch, and it is worth knowing before you buy whether a given pot will hold bulbs one year and acid-loving fruit the next, or whether you keep separate containers for each.