Old Husbands’ Tales

There are many gardening related myths, and sorting out fact from fiction can sometimes be difficult. Don took a close look at two classic old husbands’ tales – top dressing lawns, and the effect of lime on azaleas.

Tale: You should top dress your lawn every year in spring

Top dressing is probably unnecessary for most lawns, in fact if you never top dress your lawn it will still be fine. On the other hand if you bring in soil you run the risk of introducing weeds and soil-borne pathogens to your lawn, and causing drainage problems. Don’t forget that top dressing is not good for the environment, because the area where the soil was taken from will also be degraded.

What to do

Only top dress the lawn if it needs levelling and use a combination of organic soil-less mix and washed river sand that won’t affect your soil. For major holes or dips in the lawn remove or roll back the sod and fill the area beneath with good quality garden soil. Replace the sod, firming it into the new soil. Water well until the lawn is re-established. Fertilise your lawn once or twice a year (in spring and perhaps again in autumn), watering well after each application.

Tale: Lime kills azaleas

You’ve probably heard it said that azaleas planted too close to a brick wall will be killed by lime leaching out of the wall. Some people even go so far as to say that you shouldn’t place a bag of lime anywhere near an azalea. However lime does not kill azaleas, in fact a small amount is actually good for them. We did some tests with azaleas and other plants some years ago. Half a cup of lime was added to azaleas in 250mm (10") pots, and they grew magnificently. In zones with limestone soils such as Adelaide and some areas near Perth you should not use lime near azaleas, but in most areas of Australia where the soils are acid, a touch of lime won’t do azaleas any harm at all.