begonia grandis light requirements

Begonia Care

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Before deciding upon the care routine that you are going to follow, do some research about the growing requirements of the plants you want to cultivate.  Put special focus on the ideal home for them. Is it a pot, a hanging basket, a large jar or a terrarium, a greenhouse or simply, ground?

That will largely dictate the routine you are to adopt. Terrariums are ideal for small, compact varieties that need high humidity. Growing plants in a terrarium means less frequent watering, but the addition of grow lights. Yet again, larger, messy, and free-flowering varieties make the best displays in hanging containers. That’s why you’ll have to find a spot that receives light shade. In greenhouses, you will have to install fans to minimize temperatures.

In all cases, you will have to adjust the environmental conditions in a way that suits your plants.

Begonia plant in vase terrarium

Light, Temperature, and Humidity

These three variables are closely connected. Ideal temperatures are in the range of 13 to 29 degrees C during the day, that is, lower during nighttime.

The majority of begonias require a relative humidity between 40 and 60 percent. To achieve this level, you can either group the plants or buy a humidifier. Don’t mist the leaves.

Do begonias like sun or shade?

Light is the trickiest part here because begonias need different amounts of light. Too little light makes the foliage paler, whereas too much sun causes it to develop red or purple pigmentation on the leaves. It is safer to lean on the shadier side and increase the light intensity if you notice any signs.

For terrarium-grown varieties, keep grow lights on for 14 hours a day.

Begonia plant light requirements

Soil Requirements

For standard cultivation, choose a shallow pot in a slightly acidic, well-aerated medium. You can also add sand, grit, bark, perlite, and moss.

The soil for greenhouse cultivation should be comprised of sphagnum peat, grit, bark, and limestone. Also, add some slow-release fertilizer.

On the other hand, the soil mix for terrarium cultivation should consist of charcoal pieces to line the base,  sterilized and boiled sphagnum moss, combined with perlite. Avoid watering immediately after planting.

Transplant when the roots fill the containers.

Do Begonias Need a Lot Of Water and Fertilizer?

To determine how much water your begonias need, take into account the climate, growing medium, as well as the pot itself.

Generally speaking, water begonias grown in pots when the top surface becomes dry. Allow the excess water to drain out from the bottom. Use warm water, never cold.

Keep in mind that terrarium begonias don’t require frequent watering. Approximately once a month or even less than that is enough. Always use distilled water or rainwater. Check the moisture with your hands and if you overwater, remove the cover and let it dry.

On the other hand, be careful with rhizomatous, rex, and tuberous begonias in the state of dormancy. Make sure not to overwater. Symptoms of overwatering include leaf drop, root rot, and wilted stems.

Feed regularly during the active development with a 20-10-20 mix of N-P-K. Soil-less mixes need more frequent fertilizing.

Don't overwater begonias


Taking cuttings is the most widely used method to propagate begonias, along with seed propagation.

Stem cuttings: Remove the tip of a stem with three nodes with a knife, eliminate lower leaves, and place the cut end in the rooting mix. Always choose a non-flowering stem.

Leaf cuttings: Rhizomatous begonias are best propagated from leaf cuttings. Remove a young leaf with a leaf stalk, cut into smaller leaves if necessary, and place in a rooting medium so that the leaf blade is not covered.

The rooting medium for stem or leaf cuttings can be peat and sand, or moss, whereas cane-like and shrub-like begonias can also root in water. The addition of rooting hormone is optional.

While you are waiting for a plantlet to emerge, enclose them in a bag or glassy bowl, provide good light, also grow lights.

Seed propagation: Sprinkle the seeds carefully over a sterilized (covered with a foil and baked in the oven at 20 degrees for an hour) and previously moistened mix of sand and peat in a tray or a shallow pot. Use heat mats to provide additional warmth.

Pests and Diseases

Pests and diseases are the most problematic if you have a large greenhouse collection.  To prevent these, maintain good hygienic conditions, avoid overhead watering and use sterilized soil and pots.

If you notice any symptoms such as white powder, wax, stunted growth, honeydew, mucus, yellow rings or mottling, even moldy patches on the leaves, stems, or buds, that means that something is wrong with your plant.

It can be mealybugs, mites, nematodes, snails, slugs, weevils, or diseases like mildew or bacterial leaf spot. Immediately quarantine the plant to protect the plant, identify the cause and start the treatment.

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