Soil & potting mix
Best soil for Begonia 'Pin Up Flame' (Begonia × tuberhybrida 'Pin Up Flame')
Also called pin up flame begonia, bicolor tuberous begonia.
More about begonia 'pin up flame'
About Begonia 'Pin Up Flame'
Begonia × tuberhybrida 'Pin Up Flame' · also called pin up flame begonia, bicolor tuberous begonia · flowering
Begonia 'Pin Up Flame' is a tuberous begonia with large single flowers in creamy yellow boldly edged in fiery orange-red, an eye-catching bicolour that holds an RHS Award of Garden Merit. Grown as a half-hardy annual or lifted tuber, it flowers all summer in partial shade in moist, free-draining soil and is stored dry over winter.
Preferred mix: Rich, moisture-retentive but free-draining potting compost
Watch for — Tuber rot: Wet compost in growth or damp storage rots the tuber. Use free-draining compost and overwinter dry tubers somewhere cool and frost-free.
Why begonia 'pin up flame' needs this mix
Begonia 'Pin Up Flame' hates drying out, so it wants a mix that stays evenly moist — but it still needs perlite so "moist" never tips into "waterlogged".
- Begonia 'Pin Up Flame' comes from damp, shaded forest floors and has fine roots that scorch and brown the moment the rootball dries — the mix has to hold a steady reserve.
- Coir and compost give that reserve, while perlite keeps enough air that the constantly-moist mix does not turn anaerobic.
- Even moisture also keeps its thin leaves from crisping at the edges, which is this plant’s most visible stress signal.
For the full picture on what makes up a good mix, see our guide to the main types of soil and potting media — it explains why each ingredient above behaves the way it does.
What goes wrong with the wrong mix
The wrong soil is one of the most common reasons begonia 'pin up flame' struggles, and the damage often shows up weeks later as a watering problem. For this species specifically:
- A free-draining, gritty mix dries too fast for begonia 'pin up flame' — you get crispy brown edges and frond or leaf drop within days of one missed watering.
- A pure, airless peat mix swings the other way: it holds water but suffocates the fine roots and rots the crown.
- Letting the mix dry to the point it shrinks from the pot is very hard to re-wet evenly and stresses the plant badly.
Using a sharp, fast-draining "houseplant" or cactus-leaning mix that lets begonia 'pin up flame' dry out. It needs a moisture-retentive but still airy blend.
pH — does it matter for begonia 'pin up flame'?
Begonia 'Pin Up Flame' prefers a slightly acidic mix (around pH 5.5-6.5); a peat-free compost-and-coir blend sits there naturally, so routine pH testing is unnecessary.
If you want to check or adjust it, the soil pH guide walks through testing and the safe ways to nudge a mix more acidic or more alkaline.
DIY mix vs a bagged one
A good peat-free houseplant compost works for begonia 'pin up flame' straight from the bag if you mix in some perlite for air. The DIY ratio above gives a more reliable moisture-to-air balance.
Drainage and the pot
Use a pot with a drainage hole but a less-porous material (plastic or glazed) so it does not dry too fast. Bottom-watering keeps the mix evenly moist without sogging the crown.
Peat-free mixes slump and compact as they hold moisture, so refresh begonia 'pin up flame''s mix every 12-18 months to keep air in the rootball even if the pot size is unchanged. When the time comes, our repotting guide for begonia 'pin up flame' covers the timing and technique step by step.
Begonia 'Pin Up Flame' soil — frequently asked questions
What is the best soil mix for begonia 'pin up flame'?
3 parts peat-free houseplant compost : 1 part coco coir : 1 part perlite. Begonia 'Pin Up Flame' comes from damp, shaded forest floors and has fine roots that scorch and brown the moment the rootball dries — the mix has to hold a steady reserve.
Can I use normal potting soil for begonia 'pin up flame'?
A free-draining, gritty mix dries too fast for begonia 'pin up flame' — you get crispy brown edges and frond or leaf drop within days of one missed watering. A good peat-free houseplant compost works for begonia 'pin up flame' straight from the bag if you mix in some perlite for air. The DIY ratio above gives a more reliable moisture-to-air balance.
Does begonia 'pin up flame' need a special pH?
Begonia 'Pin Up Flame' prefers a slightly acidic mix (around pH 5.5-6.5); a peat-free compost-and-coir blend sits there naturally, so routine pH testing is unnecessary.
Should I buy a bagged mix or make my own for begonia 'pin up flame'?
A good peat-free houseplant compost works for begonia 'pin up flame' straight from the bag if you mix in some perlite for air. The DIY ratio above gives a more reliable moisture-to-air balance.
How often should I refresh the soil for begonia 'pin up flame'?
Peat-free mixes slump and compact as they hold moisture, so refresh begonia 'pin up flame''s mix every 12-18 months to keep air in the rootball even if the pot size is unchanged. Use a pot with a drainage hole but a less-porous material (plastic or glazed) so it does not dry too fast. Bottom-watering keeps the mix evenly moist without sogging the crown.
Keep reading
- Begonia 'Pin Up Flame' care — the full brief (light, water, humidity, problems, pet safety)
- How often to water begonia 'pin up flame' — the schedule the mix feeds into
- Repotting begonia 'pin up flame' — when and how to refresh the mix
- Soil pH guide — test it and adjust it safely
- Underwatered plant — signs and how to rehydrate it
- Why is my plant wilting? Wet vs dry diagnosis
- Should I water my plant? The simple check first
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