How to grow gloxinia

Gloxinias grow from tubers which look similar to begonia tubers, but tend to be more 'hairy'. They're rounded, brown in colour and the upper side has a hollowed-out centre, like a bowl, from which there may be protruding shoots. Many gardeners refer to gloxinia tubers as gloxinia bulbs. While technically incorrect, as bulbs and tubers are biologically different, the planting technique is the same.

How to grow gloxinias

Plant gloxinia tubers in pots of peat-free, multi-purpose compost, either individually or spaced 10-15cm apart. Water well and move to a bright spot away from direct sunlight, ideally with average temperatures of 16-24ºC. Once leaves have emerged, water only when the top of the compost is dry, aiming to keep it just moist but not wet.

How to plant gloxinia

For summer blooms, plant gloxinia tubers in spring. Soak the tubers for several hours before planting, then plant into pots of peat-free, multi-purpose compost, either individually or spaced 10-15cm apart (for individual plantings, choose a pot sized around 12cm in diameter). Place the tubers 2.5cm deep, with the hollow side facing upwards, or on its side if you can't easily see the top from the bottom. Often, gloxinia tubers have already sprouted by the time you plant them, so if there are any sprouts make sure these are facing upwards. Water the compost thoroughly and allow to drain, then move to a bright spot out of direct sunlight, such as a warm windowsill.

Spring-planted gloxinias will produce leaves within a few weeks, and then bloom by summer.

How to care for gloxinia

Water gloxinias only when the top of the compost is dry, aiming to keep it just moist but not wet, and not too dry – if allowed to dry out, gloxinias go dormant. Gloxinia leaves develop brown spots if water splashes onto them, so carefully water the compost directly, beneath the leaves. Feed fortnightly with a liquid plant food once flowers have emerged. Deadhead spent flowers to encourage more to develop.

What to do with gloxinia after flowering?

Most gloxinia house plants won't flower after the first season but there's no reason why you shouldn't try. Gloxinias need to enter a period of dormancy after flowering, so gradually reduce watering after the last bloom has faded, and eventually stop. Then remove foliage after it has turned brown. Move the pot to a cool, dark location such as a shed or spare room cupboard, where temperatures remain between 12ºC and 15ºC. Let the gloxinia tuber rest here for up to three months. When new growth appears, carefully remove the tuber from its pot and repot in to fresh compost. Give the pot a good watering and allow to drain, then place it back in a warm (18-23ºC) spot out of direct sunlight. With any luck, your gloxinia bulb will sprout leaves again and then produce flowers after a few weeks.

Pests and diseases

Like many house plants. gloxinia is susceptible to mealybugs, aphids, scale insect and fungus gnats. Hand pick any insects off the leaves and reduce watering to stop fungus gnats.

How to propagate gloxinia

Gloxinia can be propagated easily from leaf cuttings. Prepare a pot or tray filled with free-draining compost such as seed and cutting compost, or mix equal quantities of peat-free multi-purpose compost and sharp sand or perlite. Then cut a whole leaf (or several leaves) from the parent plant, with the stalk intact. Insert the stalks into the compost so the base of each leaf is just touching the surface. Water thoroughly and allow to drain, then move the pot into a propagator or cover with a clear plastic bag somewhere with bright light but indirect sunlight, with an average temperature of 20ºC.