A reader has found that the soil around his fruit trees has become quite hard and has asked should he dig around the trees to loosen the soil.
It is not a good idea to dig around fruit trees as citrus, for example, have very shallow roots. Digging around these and stone fruit trees will damage roots and quite often cause suckers to grow from the root stock. Avocado trees deeply resent any root disturbance.
Hard soil can be a problem in extreme weather conditions, particularly if the soil has not been covered with mulch. If the area is weedy, cut off the weeds at ground level rather than pulling, or digging, them out. Plants obtain most of their energy for growth from light. As you are going to deprive them of light with this method, you can leave the roots to break down and add organic matter to the topsoil.
If grass has covered the area, cut it short and, with a sharp edged spade, cut through the runners 20 cm outside the ‘drip line’ of the tree, which is the area of soil directly below the outside edge of the foliage canopy of the tree – so called because it is where rain drips off the foliage canopy and the feeder roots of trees lie in this area.
Apply a light application of organic complete fertiliser to the soil surface in the drip line area and give the tree a thorough watering, but not close to the trunk. Immediately after watering, cover the soil surface beneath the tree out to the drip line with a 3 cm layer of compost, keeping the compost at least a hands width from the trunk. Compost contains microorganisms (and often earthworms) that will help break down the weed roots and make the soil more friable.
Then cover the compost with a 5 cm layer of organic mulch to keep compost damp and deter weed growth, keeping the mulch well clear of the trunk and extending it to 20 cm beyond the drip line of the tree. Don’t use compost as mulch, as it will dry out and you will lose most of its benefits.