The RHS lavender growing guide recommends a container 30 to 40 cm across with large drainage holes, filled with peat-free multipurpose or loam-based compost such as John Innes No. 2, with lots of coarse grit mixed in, up to 25 percent by volume. It says to plant at the same depth as in the previous pot and to keep containers fairly dry in winter. These are outdoor-container instructions, and neither source gives an indoor mix.
The RHS mix
| Item | What the RHS says |
|---|---|
| Container | 30 to 40 cm diameter, large drainage holes |
| Compost | Peat-free multipurpose or loam-based, such as John Innes No. 2 |
| Grit | Lots of coarse grit, up to 25 percent by volume |
| Planting depth | Same as in the previous pot |
| Feeding | Low-nutrient soil; generally no feeding |
| Winter | Keep containers fairly dry |
Drainage and wet roots
The RHS says root rot is caused by wet or heavy soil. The University of Arkansas Cooperative Extension says lavender does best in well-drained soil and struggles when drainage is poor. Clemson says herb soil should be well drained with a pH of 6 to 7 and a moderate amount of organic matter, and that very fertile soils tend to produce lush leaves that lack flavor.
What this means indoors
A pot with no drainage hole is the likeliest way to rot the roots, and a standard houseplant mix with no grit holds more water than the RHS recipe. That is a reading of the sources, not a tested indoor recipe. See Why Indoor Lavender Dies for the other causes.
What the sources do not cover
They do not give an indoor pot size, a recommended mix for a windowsill, or a pot material. The Arkansas page warns about terracotta breaking after freezing, which applies to outdoor pots in cold climates, not to a heated room.
Frequently asked questions
How much grit should lavender have?
The RHS says lots of coarse grit, up to 25 percent by volume.
Can I use regular potting soil?
The RHS recommends peat-free multipurpose or loam-based compost with grit. Plain compost with no grit is not what it describes.
Does lavender need feeding?
The RHS says lavender prefers low-nutrient soil and generally does not need feeding.
Sources read for this page
- RHS lavender growing guide
- University of Arkansas Cooperative Extension
- Clemson HGIC herbs factsheet
Last reviewed 15 October 2026. Written by Md. Firozur Rahman. This page gives general guidance and cannot diagnose a plant from a description; see the Disclaimer. Back to Can You Grow Lavender Indoors?
Leave a Reply