Soil & potting mix
Best soil for Anne Thomson Cranesbill (Geranium 'Anne Thomson')
Also called Anne Thomson Cranesbill, Anne Thomson Geranium.
More about anne thomson cranesbill
About Anne Thomson Cranesbill
Geranium 'Anne Thomson' · also called Anne Thomson Cranesbill, Anne Thomson Geranium · flowering
Geranium 'Anne Thomson' is a hybrid of G. procurrens and G. psilostemon bred by Alan Bremner of Orkney, closely related to 'Ann Folkard' but selected for improved heat tolerance and a more compact, less-sprawling habit. The bright chartreuse young leaves mature to mid-green, and large magenta-pink flowers with a black eye and dark veins are produced abundantly all summer. The RHS awarded it AGM status in 2005. The most important care fact is to site it in sun with well-drained soil and allow space for the trailing stems. ASPCA's 'Geranium' toxic listing refers to Pelargonium; true cranesbills are not confirmed non-toxic by ASPCA, so treat with caution around pets.
Preferred mix: Moderately fertile, free-draining but moisture-retentive
Watch for — Vine weevil: White grubs in the root zone cause sudden wilting; adult notching on leaf margins is the first sign — treat with Steinernema kraussei nematodes applied to moist soil in late summer.
Why anne thomson cranesbill needs this mix
Anne Thomson Cranesbill hates drying out, so it wants a mix that stays evenly moist — but it still needs perlite so "moist" never tips into "waterlogged".
- Anne Thomson Cranesbill 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 anne thomson cranesbill 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 anne thomson cranesbill — 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 anne thomson cranesbill dry out. It needs a moisture-retentive but still airy blend.
pH — does it matter for anne thomson cranesbill?
Anne Thomson Cranesbill 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 anne thomson cranesbill 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 anne thomson cranesbill'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 anne thomson cranesbill covers the timing and technique step by step.
Anne Thomson Cranesbill soil — frequently asked questions
What is the best soil mix for anne thomson cranesbill?
3 parts peat-free houseplant compost : 1 part coco coir : 1 part perlite. Anne Thomson Cranesbill 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 anne thomson cranesbill?
A free-draining, gritty mix dries too fast for anne thomson cranesbill — you get crispy brown edges and frond or leaf drop within days of one missed watering. A good peat-free houseplant compost works for anne thomson cranesbill 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 anne thomson cranesbill need a special pH?
Anne Thomson Cranesbill 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 anne thomson cranesbill?
A good peat-free houseplant compost works for anne thomson cranesbill 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 anne thomson cranesbill?
Peat-free mixes slump and compact as they hold moisture, so refresh anne thomson cranesbill'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
- Anne Thomson Cranesbill care — the full brief (light, water, humidity, problems, pet safety)
- How often to water anne thomson cranesbill — the schedule the mix feeds into
- Repotting anne thomson cranesbill — 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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