A timely explanation ...

For tired-looking borders in the garden here's an explanation of the difference between manure, fertilizer and mulch.  Do we need all three and when to apply which of these?*

Mulching is the name given to the process of adding a layer to the surface of soil over plant roots, or even over the entire surface of soil over plant roots, or even over the entire surface of beds and borders.  This does one or more of the following - conserve moisture, feed plant roots, improve soil texture or suppress weed growth


The noun 'mulch' most often refers to something organic.  Organic mulches are a mixed, potentially confusing bunch: animal manure is generally high in nitrogen, and unless completely rotted should not come into contact with plant roots or stems.  Leaf mould and composted bark have a low nutrient level and low pH.  

They are useful for mulching woodlanders and lime-haters.  Unlike mushroom compost (second-hand animal manure, thus with lower nitrogen levels and laced with variable amounts of high pH chalk), which should be kept away from them.

Coarse bark chippings, if applied thickly enough (at least 4"/10cm), are long-lasting, suppress weeds and retain moisture well, but can deplete the soil of nitrogen as they slowly rot down (nitrogen that can, of course, be topped up using a fertiliser - read on).  And home-made compost can be rich in nutrients but is extremely variable (depending on what goes in the bin), and is seldom perfectly seed-free.  Gravel and weed-smothering black membranes are, technically speaking, inorganic mulches.

Spring is a big feeding/mulching time in the garden, just as plant growth starts, and some diligent gardeners feed their shrubs and roses again, halfway through the summer.  Most of us, I think, tend to use a combination of mulches/soil-improvers and fertilizers (both organic and inorganic) and, increasingly, slow-release inorganic ones.

Fertilisers contain essential nutrients (and minerals), in various ratios for specific purposes in order to bolster plant growth.  Most gardeners are now familiar with the fact that nitrogen encourages leaf growth, potash boosts flower production, while phosphates encourage root development and strength.  Fertiliser packets reliable carry information about nitrogen, potassium and phosphate (NPK) content that we need to know.

So-called 'balanced' fertilisers (such as traditional organic, blood fish and bone or inorganic Growmore), are those that contain more or less equal quantities of all three nutrients.

Finally, soluble and liquid fertilisers and foliar feeds are useful, being quickly absorbed by plants under stress.

One mulch I find very useful is leaf mould

*From Helen Yemm in the Saturday Telegraph, 15 February 2014, Helen's always a valuable source of information.