# Top dressing

> Top dressing is spreading dry fertiliser or amendments on the soil surface, usually under mulch, so nutrients release into the root zone as the plant is watered.

- Canonical: https://genetixbay.com/knowledge/glossary/top-dressing.html
- Also written: top dress, top-dress, top-dressing, topdressing, side dressing
- Glossary category: Systems and media · Evidence: Grower practice
- Status: Draft: awaiting expert review · Updated: 2026-10-31
- Licence: CC BY-SA 4.0 (https://creativecommons.org/licenses/by-sa/4.0/), attribute "GenetixBay cannabis glossary"

Top dressing means applying a solid fertiliser, compost or amendment to the surface of the medium rather than mixing it in or dissolving it in water. In organic and living-soil growing it is the main way of feeding: water and soil life carry nutrients down to the roots over days to weeks.

## In practice

Typical top dressings are worm castings, compost, and blended organic dry fertilisers, scratched lightly into the top 1-2 cm (about 0.5 in) and covered with mulch to keep them moist and active. Many growers top-dress around the flip and again in early flower, timed ahead of demand because release is slow. Rates follow the product's guidance; over-application can burn and attracts [fungus gnats](https://genetixbay.com/knowledge/glossary/fungus-gnat.md).

Mineral slow-release granules are also top-dressed in some soil grows.

## Don't confuse with

- **Mulch**: a protective surface cover; may or may not be a nutrient source.
- **Compost tea**: a liquid extract; top dressing is solid.

## Related terms

[Living soil](https://genetixbay.com/knowledge/glossary/living-soil.md), [Super soil](https://genetixbay.com/knowledge/glossary/super-soil.md), [No-till](https://genetixbay.com/knowledge/glossary/no-till.md), [Compost tea](https://genetixbay.com/knowledge/glossary/compost-tea.md)

## Read more

- [Living soil (no-till, water-only organic growing)](https://genetixbay.com/knowledge/systems/living-soil.md)
- [Organic vs mineral nutrition for cannabis: what the trials show](https://genetixbay.com/knowledge/nutrients/organic-vs-mineral.md)