Quick answer

Lift tuberous begonias once the leaves have yellowed and the stems have gone soft, which the first frost usually forces between late October and mid November in the UK. If a hard frost is forecast before that, lift or bring pots under cover first. Fibrous bedding, rex and cane begonias have no tuber and are not lifted.

The question of when to lift begonias UK gardeners ask every autumn has two answers, and the first is about which begonia you actually have. Only tuberous begonias are lifted and stored; everything else is composted or brought indoors as a pot plant. For the tuberous kind, the calendar gives you a window and the plant gives you the decision, so the signals come first here, then the months, the job itself and the ways it goes wrong.

Table of contents

The signals that tell you it is time

Ninety seconds at the plant answers this better than any date. Work through these in order.

First, check which begonia you have

Tuberous begonias are the big-flowered ones: Non-Stop and Illumination series, Apricot Shades, the trailing Cascade types, the Bolivian hybrids such as Bonfire and Santa Cruz, and the exhibition doubles. They have thick, fleshy stems, and if you tip one out of its pot in autumn there is a rounded, dark brown tuber at the base, hollow on top and about the size of a plum on a mature plant. These are the ones you lift.

Fibrous or wax begonias, the semperflorens bedding kind with small glossy leaves and lots of small flowers, have a mass of fine roots and no tuber. They are annuals in the UK: compost them after the first frost, or pot a few up for a windowsill. Rex, cane and Dragon Wing begonias are houseplants that have been holidaying outside. Bring them in as soon as nights drop below about 10C, usually late September, and never let them see a frost.

If you are not sure, scrape a little compost away from the base of a stem. A tuber is unmistakable. If you find only roots, there is nothing to lift.

Signal one: the leaves yellow and the stems soften

A tuberous begonia that is ready has stopped flowering, the leaves are yellowing from the bottom up and the lower stems feel soft and watery at the base. This is the plant pulling energy back into the tuber, and it starts naturally from mid October as light levels drop, frost or no frost.

A plant with firm green stems and fresh flowers is still bulking its tuber. Leave it, even if the calendar says November. The tuber you lift in three weeks will be bigger and will start better in spring.

Signal two: the first frost

Frost blackens begonia foliage overnight and the whole top collapses. This is the signal most people wait for, and it works: a light air frost forces dormancy while the tuber sits protected under a few centimetres of compost. Lift within a few days of it.

What a tuber will not survive is a hard frost, roughly minus 3C or colder, or a run of freezing nights that pushes cold into the soil. If that is forecast before your foliage has yellowed, lift anyway, or move pots into a porch or greenhouse for the last fortnight. Growers disagree about lifting before or after the first frost and both work; waiting for the leaves to yellow and using frost only as the deadline gives the best tuber.

Signal three: the stems detach

Once the top has died back, a ready stem separates from the tuber with a gentle push and leaves a clean, dry scar. A stem that tears or leaves a wet wound is not ready, and a wet scar is the commonest entry point for rot in storage. If the stems still hold, lift with them on and let them fall off during drying. Where you are still unsure, test-dig one plant: a ready tuber is firm, dark brown and dry-skinned with the roots browning off.

Month by month from September to March

UK timing moves by two to three weeks between Cornwall and Aberdeen and by a fortnight between years. Read the months below as the typical sequence for the Midlands: earlier in the north and in inland frost pockets, later on the south coast and in cities.

September: nothing to lift yet

The plants are still flowering and the tuber is still filling. Stop feeding from mid month so you are not pushing soft growth into autumn, keep deadheading, and bring rex, cane and other houseplant begonias indoors before the month ends.

October: watch the forecast, start lifting late in the month

This is the peak month for the job. From mid October, foliage begins to yellow on its own and the first frosts arrive in northern and inland gardens, so check the five-day forecast every few days. In the north, lifting typically happens in the second half of October; in the south it is more often the first half of November.

November: the main lifting month for the south

Most southern and coastal gardens get their first proper frost in November. Lift within a few days of it, and lift regardless by the end of the month even if the plants are somehow still green: cold, wet soil rots tubers whether or not it freezes.

December to February: storage and monthly checks

Nothing to lift. The job is a monthly check of stored tubers for rot, shrivelling or premature sprouting, covered below. A tuber sprouting in late February is telling you it is time to pot it up.

March: restart

Bring the tubers into the light, set them hollow side up in trays of moist compost at about 18C, and the season starts again. Late February works in a heated greenhouse or on a warm windowsill; March is safer if you only have a cool porch.

How to lift and dry the tubers

Pick a dry day if you can. Wet tubers take longer to cure and rot more often.

  1. Cut the stems back. Cut each stem to about 5cm above the tuber with secateurs. Leave that stub; it falls away cleanly during drying, and pulling it now opens a wound.
  2. Lift the whole root ball. Push a hand fork in about 10cm out from the stems, angled under the plant, and lever it up. Tubers sit shallow, usually 2 to 5cm down, so go wider rather than deeper. For pots, tip the plant out whole.
  3. Leave the soil on. Do not wash the tubers. Knock off the loose stuff and leave the rest; it comes away once dry and protects the skin in the meantime.
  4. Dry them for two to three weeks. Lay the tubers on newspaper in trays, stubs up, somewhere frost-free, airy and out of direct sun. Dry enough looks like this: the stubs pull away with a fingertip, the roots are brittle, and the soil rubs off leaving a firm, papery brown skin.
  5. Clean up. Rub off the dried soil, snap off the stubs and trim dead roots. Check every tuber for soft patches, especially around the old stem scars, and discard anything that smells or feels mushy right through.

Storing the tubers until spring

The recipe is dry, dark and cool but not freezing: 5 to 10C is the range to aim for. Bury the cleaned tubers in a tray of barely damp vermiculite, sand or dry compost so they are not touching, and cover them. Paper bags in a cardboard box work too, though tubers in bags shrivel a little more.

A frost-free shed or garage is the usual spot, and the thing to know is whether it actually stays frost-free. An insulated garage attached to the house rarely drops below 3C; a timber shed on the north side of the garden can hit minus 5C on a still January night. If you are not certain, a digital max/min thermometer left in the storage box for a week in December settles it.

Check the tubers once a month. Firm is good, slightly soft at one point wants cutting back, mushy goes in the bin. Pale shoots in January mean the spot is too warm; move them somewhere cooler and the shoots will pause.

What goes wrong and how to recover

Rot in storage

Soft, brown, wet patches, usually starting at a stem scar, are the most common loss. Caught early it is fixable: cut back with a clean knife until you reach firm, pale tissue, dust the cut with yellow sulphur or leave it to dry for a day or two, and put the tuber back in fresh, drier medium away from the others. A tuber more than half rotten is not worth saving. Rot almost always traces back to storing tubers that were not fully dry, or to stems torn off too early.

Frost got to the tuber

A frosted tuber is soft, translucent and slightly grey right through, and it smells. There is no recovery; compost it. If a tray has been through one cold night in a shed, check it a week later rather than immediately, because the damage takes a few days to show.

Shrivelled and light

A tuber that has gone wrinkled and lost weight has dried too far, usually in a heated room or an open paper bag. As long as it is still firm it will normally plump up once potted in moist compost in March. Very hard, woody tubers shrunk to half their size may not.

Frequently asked questions

Can I leave begonias in the ground over winter in the UK?

Not reliably. Tuberous begonia tubers are frost tender and rot in cold, wet winter soil, so in most of the UK they need lifting. A few survive in very sheltered, free-draining spots in the mildest coastal gardens under a thick mulch, but treat that as a gamble with spare tubers, not the plan for the ones you care about.

Do I have to lift begonias that are growing in pots?

No. Once the foliage has died back, cut the stems off, stop watering and stand the whole pot on its side in a frost-free shed or garage. The tuber stays in the dry compost until February or March, when you knock it out, check it and repot it. Lifting it out lets you inspect it for rot, which is the only real advantage.

What happens if I lift begonias too early?

You get a smaller tuber with less stored energy, which means a slower, weaker plant next year. The tuber bulks up in the last weeks while the leaves are yellowing, so lifting a plant that is still green and firm wastes that. If you have already lifted early, pot the plant up, keep it light and frost-free, and let it die back before drying it off.

How do I tell a tuberous begonia from a bedding begonia?

Tuberous begonias have large flowers, often the size of a rose, on thick fleshy stems, and a rounded brown tuber at the base when you tip the plant out. Bedding or fibrous begonias have small waxy leaves, lots of small flowers and a mass of thin roots with no tuber. If there is no tuber there is nothing to lift, so treat the plant as an annual or bring the pot indoors as a houseplant.

When do I start stored begonia tubers into growth again?

February or March. Set the tubers hollow side up in trays of moist compost with the top just showing, at around 18C in good light, and pot them on individually once shoots are a few centimetres tall. Harden them off and plant out after the last frost, which is late May in most of the UK.