Westland John Innes No 3: Why Repotting a 2-Year Fig Cuts Summer Wilt in a Half Barrel

A fig at 24 months in an Elho Vibes Fold planter or a reclaimed oak half barrel can carry more leaf than its rootball can keep hydrated on a 28C afternoon. In a 45-litre charge of peat-free multipurpose, the canopy transpires faster than the mix can resupply it. That midday droop is the roots failing to keep pace with the leaves, not the sun scorching the tissue. Westland John Innes No 3 addresses the shortfall through its recipe: roughly 7 parts sterilised loam, 3 parts peat-substitute or peat, 2 parts coarse sand or grit, and a base fertiliser charge at the No 3 rate, the most concentrated John Innes level. Loam holds water against gravity for longer than coir. The grit fraction keeps macropores open, so the rootball is not left sitting in anaerobic compost.

Midday wilt starts in the rootball

Watch the timing before blaming the weather. A fig that wilts at 13:00 and stands up again by 19:00 without extra water is pulling stored moisture from its leaf tissue faster than the roots can replace it, then rebalancing once the sun drops and evapotranspiration falls. Repeated day after day, that cycle stresses the cambium and can abort developing figs at the breba stage.

The clay-silt fraction in loam gives John Innes No 3 a larger store of plant-available water per litre than a coir multipurpose in the same container. Soil scientists describe this available water as the moisture held between field capacity and the permanent wilting point, and the loam fraction holds a good deal of it in the range where fig roots can still draw it out. A 50-litre barrel filled with No 3 can carry the plant through a hot afternoon that the same barrel filled with peat-free multipurpose may not. At 14:00, the useful difference is still in the root zone: enough extractable water remains for the fig to avoid signalling stomatal closure.

A rootball that has spiralled into a hard shell against the barrel wall will not be rescued by a better compost alone. After two full seasons in the same container, the outer 2 to 3 cm of roots need loosening at repotting so the fresh mix touches living root and can conduct water inward. Leave the rootball polished and tight, and the John Innes No 3 may sit as a damp collar around a dry, hydrophobic centre.

Repot before the buds move

Late February to mid-March is the useful window, before bud break. The fig is still dormant, disturbed roots are not being asked to supply an active canopy, and the plant then has six to eight weeks to establish into the fresh John Innes No 3 before the first warm spell pushes leaf. Moving a fig in full July leaf reliably produces the wilt the repot was meant to prevent, because cut feeder roots cannot keep up with active transpiration.

Choose between one barrel size up and a refresh in the same container. If the roots have already filled a 50-litre half barrel, cropping is often better when the fig stays root-restricted in that volume, with the top 10 cm of spent medium scraped away and replaced with fresh No 3. A move into a 90-litre tub gives the roots more space, but the plant may put that gain into vegetative growth and delay fruiting. Ficus carica fruits harder when the roots feel a boundary, a response commercial fig growers use deliberately.

Do the drainage work while the plant is out. Drill or clear at least four 20 mm holes in the base, lay in a 3 to 4 cm layer of 20 mm gravel or broken crock, and stand the barrel on pot feet so the holes cannot seal against a patio. John Innes No 3 is designed to drain freely, but a blocked base can turn any loam mix into a stagnant column within a fortnight.

What watering looks like in a loam barrel

A hand-watered 50-litre barrel rarely wets evenly on the first pass. Water beads and runs, finds the slight gap between compost and timber or plastic, then appears at the base while the centre of the rootball is still short of moisture. To bring the whole barrel to field capacity, water until it runs from the drainage holes, pause, and water again.

A dry coir-heavy mix often sheds water straight off the top, while a loam-based John Innes fill darkens more slowly and takes the water in at its own pace. The side channel can still happen after a dry spell, especially where the old rootball has pulled away from the wall. That is why a second pass after a pause matters more than the first gush from the base.

A Hozelock Flexi Spray or the Hozelock automatic watering kit with 4 mm micro-tube and two adjustable drippers per barrel gives a steadier wetting pattern. At low pressure, those drippers deliver 2 to 4 litres per hour and wet the full column instead of sheeting water off the top. The drippers should sit far enough apart to cover both the old rootball and the newer outer ring of John Innes No 3.

In peak summer, set the timer around the plant’s daily rhythm: early morning and again near 16:00. Runs of 8 to 12 minutes suit many barrels, depending on the actual dripper flow. Shorter repeated watering works better than one long soak because the loam absorbs at a finite rate; once that rate is exceeded, the surplus drains through the base and carries some of the fertiliser charge with it.

Across a July week, a fig in a barrel on drip typically uses 6 to 10 litres a day. A hose timer meters that more consistently than memory, especially when the barrel is heating from the sides as well as from the top.

The autumn setting has to change. From late September, drop the Hozelock schedule to a single short cycle every third day, then switch it off once the fig drops its leaves. Through a wet British winter, a dormant fig left in perpetually wet John Innes No 3 is on the quickest path to root rot, since the loam fraction holds moisture for far longer than a free-draining coir mix.

Winter protection for a barrel that stays put

A planted half barrel is usually too heavy to move, so the fig overwinters where it stands. From December, wrap the barrel sides in hessian or bubble insulation, because the root zone freezes inward from the container wall and a 50-litre volume of John Innes No 3 has less thermal mass than open ground.

Hardy Ficus carica cultivars such as Brown Turkey tolerate British winters to around minus 8C at the root, provided the medium is not waterlogged. That tolerance depends on the same practical details used in autumn: drip line off, drainage holes clear, barrel lifted clear of the patio.

Leave the ripe embryo figs on the plant, the pea-sized ones sitting near the branch tips. They overwinter and form next year’s first crop. Larger unripened figs that will not make it should be removed, since they rot and drop without helping the plant. Fleece belongs over the canopy only when a hard frost is forecast; permanent wrapping traps damp and invites botrytis.

Slugs and snails climb a moist barrel in spring and graze the new fig shoots, so a thin ring of ferric phosphate pellets on the compost surface and at the barrel foot earns its place here. The ferric phosphate type, sold as Sluggo or Growing Success Advanced, degrades to iron and phosphate in the soil and does not carry the pet and hedgehog toxicity of the older metaldehyde products withdrawn from UK sale in 2022.

Reading the fig after the move

A fig that keeps its leaves flat and turgid through a 30C afternoon in the first summer after moving to John Innes No 3 has shown that the root-zone water buffer is doing its job. If it still droops by 14:00 on the hottest days, and the drainage and watering are both right, the container volume is the ceiling the roots have run into.

When that happens, the next season’s decision is whether to stay root-restricted for the sake of the crop or to give the plant the larger tub it is asking for, knowing the trade against fruiting still stands. That choice is one the leaf cannot make for you.