Begonia care

How often to water a begonia

Clemson Cooperative Extension’s advice for indoor begonias is to keep the soil evenly moist, allowing it to dry a little between waterings, to reduce water in winter, and never to let the pot sit in a saucer of water. University of Minnesota Extension adds that begonias are highly susceptible to root rot, and that by the time the symptoms show it is usually too late to cure.

Water at the base of the plant when you can. Minnesota Extension recommends it to avoid fungal leaf diseases.

Light and humidity

The two extension sources agree on the principle and differ on the amount. Clemson puts flowering begonias in a bright spot that gets some direct sun, such as early morning sun in an east window, and puts foliage begonias such as rex types in a bright spot away from direct sun. University of Minnesota Extension says begonias prefer shade over direct sun, tolerate morning sun, and should avoid afternoon sun.

The sensible reading is that rex and other foliage types want the gentler end of that range, and flowering types can take a little morning sun.

Humidity: Humid air; spray the air around it rather than misting the leaves.

Why is my begonia dying?

Humidity is the common trouble indoors. Clemson says a humid environment is needed but misting is not recommended, and advises spraying the surrounding air instead. For foliage begonias it gives a temperature of 66 to 73°F, with nights not dropping below 55°F.

The pests Clemson lists are mealybugs, whiteflies and spider mites, and it says diseases are an infrequent problem in the home. Minnesota Extension names powdery mildew and says good air circulation helps prevent leaf diseases.

Feed with a balanced liquid fertilizer at half strength on alternate waterings, as Clemson advises, and repot in spring.

How to propagate a begonia

University of Minnesota Extension says begonias are easily propagated by cuttings in about three to four weeks. Take a 2 to 3 inch section, strip the lower leaves, stand it in water until roots form, then pot it.

Clemson adds that a begonia that has become pot-bound can be divided when you repot it in spring.

Keeping it alive when you share a home

In a shared household, a begonia needs one person who watches the soil and the humidity, because the two things it dislikes are opposites: soggy soil and dry air.

Because the ASPCA lists it as toxic to cats and dogs, keep the pot where the animals do not dig or chew. The ASPCA says the most toxic part is underground, which is a reason to keep a pet out of the soil as well as off the leaves.

If you use Family Greenhouse for this, sharing plants with a household explains who sees what and who gets reminded.

The honest bit

My take: begonia is a name for hundreds of plants, and the advice on a tag for one type is not always right for another. Find out whether yours is a rex, a cane or a wax begonia before you copy a schedule.

The ASPCA lists begonia (Begonia spp.) as toxic to cats and dogs. It names soluble calcium oxalates, lists vomiting and drooling in dogs and cats, mentions kidney failure in grazing animals, and says the most toxic part is underground. University of Minnesota Extension also calls begonias toxic to cats and dogs. If a pet has eaten some, call your vet or a poison hotline. The pet-safety page for begonia shows the listing, and the free pet-safe checker covers the rest of your plants.

Begonia FAQ

How often should I water a begonia?

When the top of the soil has dried slightly, keeping it evenly moist and never soggy, and less in winter. Clemson Cooperative Extension gives that rule for indoor begonias.

Why are my begonia’s leaf edges turning brown?

Dry air is the usual suspect, since begonias need a humid environment. Clemson advises spraying the air around the plant rather than misting the leaves. Uneven watering is the other thing to check.

Which kinds of begonia does this guide cover?

The common houseplant types: rex and other foliage begonias, cane-stemmed begonias and wax begonias. Tuberous begonias are grown from tubers that are dug up and stored in the fall, so their care is different.

Is a begonia toxic to cats and dogs?

Yes. The ASPCA lists Begonia (Begonia spp.) as toxic to cats and dogs. Toxic to cats and dogs per the ASPCA, which names soluble calcium oxalates and lists vomiting and drooling in dogs and cats. It adds that the most toxic part is underground. If your pet has eaten some, call your vet or a poison hotline.