Begonia’s can be grown from both tubers and seeds, if you want to know how to start begonia tubers read our article here. But if you want to learn how to grow begonias from seed then read on.
While most people are aware of tuberous begonias not many gardeners also know they can be easily grown from seed too.
Step 1 – Fill a seed tray with compost
Grab a seed tray or seed trays and fill it around two-thirds with multi-purpose compost.
If you have a sieve then it is always a good idea to sieve the compost first. If you don’t have one there’s no need to worry just break down any large clumps of compost using your hands.
Begonia seeds are tiny, so big clumps of compost can be a real problem for them.
Step 2 – Wet the compost
Now we wet the compost. I like to do this step before sowing the seeds as it reduces the chances of washing them away.
Watering after sowing can wash away any little seeds, and begonia seeds are definitely little.
You can use a spray bottle if you have one to mist the compost, or if not just gently pour some water in with a watering can.
Step 3 – Sow seeds onto the surface
Place your seeds onto the surface of the compost, roughly 1 to 1.5cm apart.
You do not want to cover the begonia seeds as light is essential to their germination.
Step 4 – Press into the soil surface
As I previously said you do not want to cover the seeds. Instead lightly press them into the surface, just enough to ensure there is good contact between the seed and the compost.
Step 5 – Cover
Now you want to cover the seed tray with a clear cover.
Either use a propagator or cover the tray with a sheet of glass or perspex.
Step 6 – Keep at 16 – 20 degrees
Keep the seeds between 16 – 20 degrees celsius, as this is the optimum temperature range for germination.
A window sill above a radiator can work well. If you don’t have anywhere that is a suitable temperature, then a heated seed mat can work wonders.
Step 7 – Transfer into pots
Once the begonia seedlings have begun growing and are around 2-3cm tall it is time to start thinking about potting them on.
Delicately remove them from the tray and pot on into something around a 10cm pot.
I have found a teaspoon works well as a seedling lifting tool. Use fresh compost when repotting the seedlings.
Step 8 – Harden off
Acclimatise your plants to outside life by moving the plants outdoors during the day before bringing them back in at night.
Continue doing this until planting them out when all danger of frost has passed.