Growing instructions
“It's easy to grow tuberous begonias”
Your decision to grow tuberous begonias will be rewarded with the most spectacular blooms in the flower kingdom. If this is your first time growing begonias, please read and familiarize yourself with the following information. The most important aspects are highlighted.
SOIL PREPARATION 
Tuberous begonias can survive in many different types of soil. The most important factor being perfect drainage. A mix of coarse sand and bark is ideal for tuberous begonias, with a teaspoon or two (depending on the size of the pot) of slow release fertilizer (begonia food). The same factor applies for planting your begonias outside - perfect drainage. You can achieve this by raising your beds and adding sand and organic matter if your soil is clay type, and if your sandy you would need to add some organic matter.
STARTING TUBEROUS BEGONIAS
It is very important that a sprout appears before the tuber is planted. If your tubers seem slow to sprout, move them to a warm dark place. When the sprouts appear the tubers are ready to be planted.
POTTING
Fill your pot with bark compost mix and add the fertilizer, add some more mix and then place your tuber on the mix. cover tuber with the mix. It is essential for good root development that the tubers are completely covered as the roots develop from the top and sides of the tuber. Water lightly, but thoroughly, and do not water again until the surface of the soil shows dryness. Place your pots in a warm place where they will receive filtered sunlight. Water only when the surface of the soil shows dryness.
WIND
Some protection from the wind is essential, they can be damaged by strong winds. light breezes are beneficial.
FROST
In the spring begonias should be placed outside after all danger of frost has passed. The first light frosts of autumn/winter will not harm tubers.
ENVIRONMENT
Sunlight - Begonias do best in partial shade or filtered sunlight. often this is the key to success. Exposure to excess sunlight results in burnt foliage and flowers. At the other extreme, too much shade results in lush foliage, and few if any flowers.
The more sunlight a begonia receives without burning, the larger and more abundant the flowers will be.
DROPPING OF BUDS
Begonias, although hardy and easy to grow, are affected by over watering and dense shade. As a result they will not bloom properly. They require fresh air circulation, and will drop their buds and flowers if kept in a stuffy atmosphere with no ventilation. If the centre buds fall before they open, it is usually a sign that the soil is kept too wet. Care should be taken to avoid overwatering. If your plants become tall and spindly, with large leaves and few flowers, there is insufficient light. This can be remedied by moving your begonia to a less shaded site.
HOW TO WATER
Watering is one of the most important factors in successfully growing begonias. Begonias do require a little more water than the average garden plant but the Most common mistake made in growing begonias is over watering. The amount of water depends on the size of the plant, size of pot, type of soil or mix, and weather conditions etc. The frequency of watering depends on the same factors - for these reasons it is difficult to set down any hard and fast rules on how to water. Water carefully, only water when the surface of the soil is starting to dry out.
DORMANT TUBERS
Depending on the season, in early May stop watering your tubers, this will encourage them to become dormant. Do not dig your tubers or take them out of their pots until the foliage knocks away with a brush of the hand as it is this late stage that the tubers increase in size and store energy for the following year. After the foliage knocks away, tubers should be removed from the soil or pots. Brush the soil from the tuber and store them in a warm sunny place. Remove any trace of the old stem, and when the tubers are thoroughly dry, store them in a dry place for winter. Do not store the tuber until they are thoroughly dry!