How to Grow Begonias from Tuberous Roots

Begonias are magnificent flowers that closely resemble roses and come in a wide variety of vibrant colors. Typically, these flowers are grown from tubers in early spring. Unlike many other plants, begonias thrive in shaded areas rather than direct sunlight, which is why they are so popular among gardeners. Once they sprout, begonias are capable of flourishing in a wide range of climates.

Buy Begonia Tubers in Mid-Winter. Since begonias are best planted in early spring, the ideal time to choose your tubers is in mid-winter. There are hundreds of begonia varieties to choose from, but all require the same general care. You can research different varieties through catalogs or online to decide which one to plant.

• There are more than a thousand begonia varieties, but not all are tuberous. Different types may require different care techniques.
• Begonias come in many flower sizes, with diameters ranging from over 1 cm to 30 cm. They are available in a variety of colors, except for blue.
• The Cascading begonia, like the one in the illustration, is perfect for hanging baskets as it grows outward and cascades down. Upright types like the Nonstop begonia grow to about 30 cm tall.

Plant begonias indoors one month before the first frost arrives. In areas with climates that dip low enough for frost, you’ll need to start growing begonias indoors. If you live in a tropical climate with no frost, you can plant them directly in the ground.

• If your area experiences particularly hot summers, it’s recommended to plant begonias a little earlier so that the plant can strengthen before the peak heat arrives.

Plant in small pots or trays. Choose a high-quality potting mix with good drainage, such as peat moss soil. Moisten the soil by filling a bucket with it and watering until it’s damp but not soggy. Fill the pot or tray to about 1.2 cm below the rim. Place the begonia tuber in the soil, concave side up, spacing each tuber about 7.5 cm apart. Cover with about 1.2 cm of soil.

• Use a 15 cm pot to plant up to 2 small tubers, each about 2.5 – 7.5 cm in diameter, or one large tuber. For a 25 cm pot or basket, you can plant 3 small tubers.
• If you're unsure about what kind of soil to buy, consider purchasing a soil-less mix and combine 3 parts of it with 1 part construction sand. This will provide the proper drainage for begonias.
• Be cautious when handling begonia tubers, as they won't sprout if damaged. Look for tiny pink shoots or old scars on the tuber if the concave side is unclear. This indicates the growing tip and should be placed facing upwards.
• Ensure the pot or tray has drainage holes.

Place the tray or pot on a windowsill with sunlight and wait for sprouting. Begonia tubers need strong light, but not direct sunlight; otherwise, they may overheat. Keep the soil moist, but not waterlogged, for about a month. The tuber should sprout within 2-4 weeks, and you can transplant it once the last frost has passed.

• Maintain room temperature at around 21°C or higher. Temperatures below this will prevent the tuber from sprouting.
• If the begonia shoots grow taller than 5 cm before the ground thaws enough to plant outdoors, transplant it into a larger pot to allow the plant to continue growing. However, the pot doesn’t need to be larger than 30 cm. If you plan to keep the plant in a pot, simply transfer it to the pot you plan to use for its final growth.

Prepare the soil for planting. Begonias should be planted in a location that receives partial shade, avoiding full sun or complete shade. Some sunlight is ideal, but the plant will struggle to bloom if it’s exposed to too much sun. Areas that receive morning or late afternoon sunlight are best, as the sun is less intense during these times. Find a sheltered spot to prevent the delicate flowers from being blown away by strong winds during blooming.

• The climate of your area is also an important factor. If you live in a cooler climate, your begonias will tolerate sunlight better than in warmer areas.
• If the soil is dry or doesn’t drain well, you can till it to a depth of about 13 cm and add compost or other organic materials to improve drainage.

Plant begonias that have already sprouted. Dig holes about 5 cm deep, spacing them approximately 20 cm apart. Place the young plants into the holes and gently firm the soil around the tuber. Do not plant the tuber more than 2.5 cm deep, whether you are planting in the ground or in pots.

Water the plants when the soil is dry. Insert your finger into the soil to a depth of about 5 cm to check moisture levels. If the soil feels dry and crumbly, water generously. Try to avoid watering in the middle of growing clusters of leaves as this could encourage mold growth. Focus on watering near the base of the plant.

• If planting in pots, water until the excess runs out through the drainage holes at the bottom of the pot, and be sure to empty any water that collects in the saucer underneath the pot.
• For the largest and most vibrant flowers, consider fertilizing every two weeks with a bloom fertilizer, following the instructions on the packaging.

Regularly remove faded flowers. Begonias will bloom throughout the season, so be sure to check the plants often and remove any withered or spent flowers. This will allow the plant to focus its energy on producing new blooms.

Use stakes for support if needed. Tall begonia varieties can grow large enough to topple over, so using stakes can help prevent breakage. Insert bamboo or wooden stakes a few centimeters from the main stem. Tie the plant to the stake using garden twine. As the plant continues to grow, you may need to add more ties to keep it upright.

Gradually reduce watering. As the autumn winds begin to arrive in November, you should gradually decrease watering until it stops entirely. This will help your begonias enter a dormant state throughout the winter. You can do this for both garden and potted begonias.

• If you live in a hot climate, forcing the plant into dormancy is unnecessary, as begonias can survive the winter outdoors. Prune the plant in the winter, and it will grow back in early spring.

Dig up the bulbs. Use a spade to carefully dig up the bulbs along with the surrounding soil. Place them in a sunny spot in your shed or garage for about a week to dry out. Store the begonia bulbs in trays lined with peat moss or sand, and keep them in a cool, dry place throughout the winter.

• If you live in an area where the ground never freezes, there’s no need to dig up the bulbs.

Replant the bulbs in early spring. Plant the begonias as you initially did, allowing them to sprout indoors during the spring, and then move them outside after the final frost and when the soil has thawed.

• Each year, the begonia bulbs will grow larger. However, begonias are generally not long-lived, and their bulbs will only thrive for a few years.
• Dig up the bulbs or bring the potted plants indoors before the cold weather sets in late in autumn. Trim the begonia branches and store the bulbs in peat moss or in their pots, placing them in a cool, dark, and dry location until the next spring, when you can replant them as previously described.
• At the end of the growing season, begonia tubers need to rest and won’t bloom during the winter. Even plants in warmer climates need a few months of dormancy.
• Choose the largest bulbs you can find for the most beautiful begonia flowers. Smaller bulbs usually bloom in the first year, but larger bulbs will produce stunning, magnificent flowers.

• Do not allow the begonia seedling pots to become waterlogged. The bulbs or newly sprouted stems will rot.
• Excessive heat and humidity are not ideal for begonia tuber plants.

• Begonia bulbs/tubers
• Plant pots
• Planting soil
• Fertilizer for flowering plants