Gadenin日本語Get the appPick the pot for the winter move, not for the tree
Most people size a lemon pot by the tree and regret it the first cold night, when they discover they cannot lift it. A pot you cannot shift on your own is a pot that stays outside through a frost. Decide first how you will move it, then choose the size.
A young tree with a rootball around eight inches (20 cm) across goes into a 12 inch (30 cm) pot. Step up two to four inches (5-10 cm) of diameter at a time, every second or third year, until you reach a working ceiling of about 18 to 20 inches (45-50 cm). At that point stop increasing the pot and root prune instead. Plastic and glazed pots hold water longer than terracotta, which is an advantage in summer heat and a liability in a cold winter room.
Put the pot on a wheeled plant caddy before you fill it. Once the compost is in and wet, a 20 inch pot with a tree in it weighs upward of 90 pounds (40 kg) and you will not get a caddy underneath it without help.
| Tree age | Pot diameter | Move by |
|---|---|---|
| First year from the nursery | 12 in (30 cm) | Two hands |
| Two to four years | 14-16 in (35-40 cm) | Caddy |
| Five years and older | 18-20 in (45-50 cm) | Caddy, two people |
| Mature, held at size | 18-20 in (45-50 cm) | Root prune, do not go bigger |
A gritty mix, not a peat-based potting mix
Lemons are more sensitive to airless roots than to poor soil. A standard all-purpose potting mix, watered by someone who is being careful, turns into a wet sponge by midwinter and the roots suffocate. Cut it hard with grit so that water runs through in a couple of seconds.
Aim for roughly two parts good potting mix, one part composted bark or coir, and one part coarse grit or perlite around a quarter of an inch (5 mm). Add a slow release citrus feed at the rate on the label. Skip the layer of crocks at the bottom, which raises the saturated zone rather than lowering it; a single piece of mesh over the hole is enough.
Test the mix before the tree goes in. Fill the pot, water it hard, and count. Water should stop running from the base within about ten seconds. If it dribbles for a minute, add more grit.
Plant high and keep the graft union clear
Nearly every lemon you buy is grafted, and the swollen union sits two to six inches (5-15 cm) above the roots. Bury it and you invite rot at the union, and you also let the scion root over the top of the rootstock, which throws away the rootstock's vigor and cold tolerance.
Set the tree so the top of the rootball sits about half an inch (1 cm) proud of the finished compost level, with the union clearly in the air. Do not tease the roots apart unless they are circling; if they are, slice three vertical cuts an inch (2.5 cm) deep down the sides of the rootball with a clean knife.
- Part fill and set the height Put enough mix in the base that the rootball shoulder finishes about an inch (2.5 cm) below the pot rim. Sit the tree in and sight across the rim from eye level before you backfill anything.
- Backfill in stages Add mix a third at a time and tap the pot on the ground between each. Do not press hard with your thumbs; compacting a gritty mix undoes the drainage you just built.
- Water until it runs Water slowly until it runs from the base, wait ten minutes, then water again. The second watering wets the dry pockets the first one ran past.
- Stake only if it rocks A tree that rocks in wind tears its new roots. Use one short cane to the lower trunk and remove it after a season. A tall rigid stake gives you a weak trunk.
- Leave the feed alone for a month The slow release in the mix is enough. Liquid feeding a freshly potted tree pushes soft growth before the roots can support it, and soft growth is what leafminer and scale go for.
Where to stand it outdoors
Give it the sunniest spot you have, with at least six hours of direct sun, and shelter from wind. Wind is the underrated problem: it dries a container far faster than sun does, and it scars young fruit against the thorns until the skin is marked for good.
A wall that faces the midday sun is ideal, standing the pot about a foot (30 cm) off it so air still moves behind the tree. Raise the pot on feet so the drainage hole is never sitting in a saucer of water. Save the saucer for indoors, and empty it there too.
Write down where the pot stood and how many hours of sun that spot actually got. Sun moves a lot between early and late summer, and next year the note is worth more than your memory of it.