Planting a Fig Tree: Restrict the Roots to Get Fruit

Why a happy fig is a bad fig

A fig is one of the few fruits where generosity works against you. Given deep soil, plenty of nitrogen and unlimited root run, it does exactly what the roots tell it to do: it makes wood. Shoots run three to six feet (90 to 180 cm) in a season, the leaves come huge, the internodes stretch, and the figs that do form sit at the far end of growth that never slowed down enough to ripen them.

Restrict the roots and the tree changes character within a season or two. Shoot extension drops to twelve to twenty inches (30 to 50 cm), the internodes shorten, and figs appear in the leaf axils close to the base of the new wood, where the tree can actually finish them. This is not a trick or a stress treatment invented by gardeners. It is how figs behave on the thin, stony, drought-prone ground they come from.

If you have already planted a fig into open ground and it is all leaf, you do not have to dig it up. Cutting a trench with a spade around the tree at a radius of about two feet (60 cm), straight down to eighteen inches (45 cm), severs the outer roots and usually brings a crop within two seasons.

Building a root restriction pit

The classic method is to plant into a box built in the ground: a pit lined on four sides so the roots cannot run sideways, with the bottom left partly open so the tree can still reach water in a drought. Anything rigid works, and the material matters far less than the volume.

1. Dig a pit about two feet cube Aim for roughly 24 by 24 inches wide and 24 inches deep (60 by 60 by 60 cm). Bigger than three feet (90 cm) across and the restriction stops working; much smaller and you will be watering twice a day all summer.
2. Line the four sides Use paving slabs, sheets of fiber cement, bricks laid dry, or corrugated sheet. The lining should finish an inch (2 to 3 cm) above soil level so surface roots cannot creep over the top.
3. Restrict the bottom too, but not completely Put four to six inches (10 to 15 cm) of rubble, broken tile or coarse gravel in the base. This slows the taproot without sealing the pit, so the tree drains freely and can still find deep moisture in a dry spell.
4. Refill with lean soil Use the soil you dug out, with a little grit and no more than one part in ten of compost. Rich compost inside the pit undoes the restriction, because the roots simply feast on what is in the box.
5. Check the sides every few years Roots eventually find a gap and escape. If growth suddenly doubles and fruiting falls off, run a spade down each side of the pit in winter to cut whatever got out.

Site: the hottest, brightest, driest place you have

Figs ripen on accumulated heat, not on time. A tree in six hours of sun will grow perfectly well and still hand you hard green fruit in autumn, because it never banked enough warmth to finish the crop. Give it eight hours or more, and give it reflected heat if you can get it.

A south or south-west facing wall is worth more than a whole extra hour of sun in the open. The wall stores heat during the day and releases it overnight, which lifts the average temperature the fruit experiences and pulls ripening forward by one to three weeks. It also keeps winter cold off the wood, which matters because the embryonic fruit that becomes next year's early crop has to survive the winter on the branch.

Soil, pH and what not to add

Figs are not fussy about soil type, and they tolerate alkaline ground better than almost any other fruit. Anything from pH 6.0 to 7.8 is comfortable. What they will not tolerate is waterlogging: roots sitting in cold wet soil through winter rot, and the first sign in spring is buds that swell and then stall.

Keep the planting mixture deliberately lean. No manure, no rich compost, no general fertilizer at planting. A handful of bone meal or a low-nitrogen slow-release feed is as much as the tree needs to establish. Every bit of nitrogen you put in the hole buys you leaves you did not want.

On heavy clay, raise the whole planting area by six to eight inches (15 to 20 cm) rather than digging a deeper hole. A deep hole in clay becomes a sump, and a fig will not forgive standing water.

Planting and the first season

Plant while the tree is dormant, from leaf fall to just before bud break, in any climate where the ground is workable. In areas with hard freezes, wait until the worst of winter has passed so the young wood is not sitting exposed for months. A container-grown tree can go in during the growing season, but it will need watering all summer.

1. Set it at the same depth it was grown Do not bury the stem. Find the soil mark on the trunk and match it. Figs sucker readily from the base, and a buried stem produces a thicket of shoots you will be removing for years.
2. Spread the roots outward, not down Tease the outer roots free of the rootball and lay them out horizontally. Roots that stay in a spiral from the pot keep circling and the tree never anchors properly.
3. Firm, then water once and hard Tread the soil in firmly and give five to eight gallons (20 to 30 L) in one go to settle it. Frequent light watering after planting encourages a shallow root plate right where the summer heat dries out.
4. Cut back the top Take the leading shoots back by about a third at planting. This balances the top against the roots you disturbed and forces low branching, which is what you want for a tree you will be picking by hand.
5. Do not feed in the first year The tree has enough. Feeding a newly planted fig produces soft growth that neither ripens nor hardens off, and the first winter takes it back.

Spacing, and what to write down

With restricted roots, a fig stays a manageable eight to twelve feet (2.5 to 3.5 m) across. Space free-standing trees twelve to fifteen feet (3.5 to 4.5 m) apart, and fan-trained trees against a wall about ten feet (3 m) apart. Unrestricted in warm climates the same tree will reach twenty-five feet (7.5 m) and shade out everything under it.

Write down the planting date, the exact dimensions of the pit or the container volume, and the position of the tree relative to the wall or fence. In three years, when you are trying to work out why one tree fruits and another does not, that note is the only evidence you will have. Add a line each winter recording the longest shoot you cut off: shoot extension is the single most useful number for judging whether the root restriction is still doing its job.