Manure On Top or Down Deep? 

When applying organic material to your beds should you top-dress or dig it in?

I have been gardening for more years than I care to contemplate and in that time some gardening advice has changed.

I spent many years when I was younger digging in compost, rotted manure and seaweed. The deeper the better. That is what you did then. The idea was simple; get the nutrients down into the soil where the roots of the plants are. However, thinking has changed; as we have gained a greater understanding of the role of micro-organisms in soils and the stratification of complex soil ecosystems the advice for established beds is to top-dress. It is now realised that there are different soil ecosystems on the surface, just below the surface and deeper down, and digging these over disrupts the layers which will take some time to re-establish.

Resist the urge to dig in the organic matter; the complex soil ecosystem of established beds is best left undisturbed. Nutrients added to the top will move their way down into the soil where they will be available to the plant roots and beneficial micro-organisms. Top dress garden beds with compost or well-rotted manure or seaweed in preparation for spring planting. As a top dressing, the organic matter will also act as a mulch and help suppress spring weeds.

However, if the bed your working on is new and has not been cultivated recently, I still believe it is best to dig in the organic matter, to begin with. Then when the soil has settled down, move to top dressing.

David Brittain
Kiwicare