Soil for coleus – and how to repot

Coleus plants are not fussy, but on one point they will not compromise: airy, porous and well-drained soil. Heavy, wet soil is the most common cause of root problems. Here we share what we know works – the right soil mix, and how to repot.

The best soil for coleus

Start with a good-quality ordinary potting soil and make it airier:

• Basic recipe: about 1 part perlite to 4 parts potting soil – around 20%. The perlite keeps the soil airy and lets excess water drain away.
• Avoid: heavy peat-based soil that compacts down, and soil with pre-mixed "water-retaining gel" – coleus plants don't want to sit in wet soil.
• Pot: a clay pot with drainage holes and a saucer – the clay breathes, the soil gets more air and excess water drains away. A tip is to put Leca balls at the bottom.
• Size: don't skimp – a bigger pot gives a bigger plant. The only catch is that you need to keep an eye on the watering: in a large pot it takes time before the soil around the root ball dries out. So don't water on a schedule, but when the soil starts to dry: stick a finger in, or lift the pot – if it feels light, it is time.

When should coleus plants be repotted?

• Roots coming out of the drainage holes or soil that dries out in a day → the pot is too small.
• Spring is the best time – the plant is entering its growing season and will quickly fill the new pot.
• Newly bought young plants and rooted cuttings are repotted once the root ball holds the soil together.

And what about the old claim that coleus "like a tight pot"? There is something to it – but not what you might think. A bigger pot holds moisture longer, so anyone who waters by routine can easily drown the roots. The plant needs room to grow, and in a pot that is too tight, growth easily comes to a halt.

Repotting – step by step

1. Water the plant the day before – a moist root ball slides out of the pot easily.
2. Choose a pot 2–5 cm wider than the old one.
3. Carefully loosen the outer roots if the root ball is tightly root-bound.
4. Plant at the same depth as before, water thoroughly, let it drain.
5. Wait a couple of weeks before feeding – fresh soil is enough, and newly moved roots burn easily.
6. Feel free to trim at the same time – repotting + trimming in spring is the recipe for a bushy summer plant (how to trim).

Soil for sowing

Fine-grained sowing soil is a safe choice when you sow – but ordinary potting soil works well too. The complete sowing guide: How to grow coleus plants from seeds.

Frequently asked questions

What is the best soil for coleus?

Airy and well-drained: potting soil + about 20% perlite.

How often should coleus plants be repotted?

When the roots fill the pot – for young plants, often several times in the first year, then usually every spring.

Is ordinary potting soil enough on its own?

Almost – mix in perlite, as pure potting soil easily becomes too compact and wet.

Articles