Gardeners' Queries-

Press, Volume C, Issue 29499, 28 April 1961, Page 8

Gardeners ' Queries-

A typographical slip occurred in last week's answer to “Lazybones,” of Ashburton. Phytazol "A” is used at Jib per 1000 square feet, not 100 as stated The next sentence in the reply pave the correct information when it stated that 2 ounces are used in a gallon of water to cover 250 square feet.

I have had a large quantity of sawdust given to me, but 1 am rather doubtful about Its use in the garden, since experts seem to hold widely differing views. Some say it can be used and others do not agree. 1 would be glad If yon could sum up the position for me. (“Finns” St. Albans.) Like all things horticultural. 1 believe that the answer lies in moderation, and in the way it is used, for I have seen both good and bad results from the use of sawdust. The first point to appreciate is that new sawdust requires nitrogen to decay. The bacteria which rot down sawdust take nitrogen trom the soil to carry out the job. and consequently there js 'ess left for plants. If the quantity of sawdust applied to the soil is excessive, then plants will suffer from nitrogen starvation unless a fertiliser which contains it. such as blood and bone, is applied before the sawdust Fresh sawdust is best applied as a mulch on the surface of the soil, rather than worked into the soil. Applied this way it holds water in the soil, and Is particularly beneficial to surface rooting plants such as azaleas and rhododendrons. Even so it is not wise to apply a depth greater than 2 to 3 inches at a time, together with blood and bone at 3 to 4 ounces per square yard. It is when fresh sawdust is worked direct into the sol) that trouble comes, tor it can depress growth, even when fertiliser is applied. When the sawdust has weathered for two or three years it is much less likely to cause trouble, and is then a nice friable material, almost black. A well-decayed mulch is quite suitable to mix with the soil, and has a particularly beneficial effect on the soil texture, enabling it to break down into “crumbs" quite readily. Incidentally, sawdust mulch may be applied any time now.