Gardeners’ queries

Press, 22 October 1976, Page 10

Gardeners’ queries

Could you please advise me the correct time of year for sowing Brussels sprouts seed? What are the best varieties and what is the best insecticide for controlling greenfly, aphids etc? — T. McC. (R.D. Christchurch).

Seed of Brussels siprouts should be sown no later than about mid-November in Canterbury. Popular varieties include Fillbasket, Emerald Ball, Jade Cross and Jade E Hybrid. Greenfly and aphids are two names for the same insect and can be controlled with menazon or maldison. Caterpillars can be controlled by applying carbaryl or diazinon, the latter also giving control against aphids. Lindane, if obtainable, provides an excellent safeguard for newly planted sprouts. Derris dust can also be used during the season.

Please could you say something about olive trees? We have planted one recently and have been told it takes 25 years before they fruit. Is this true? Also, how does one preserve the fruit and what method is used to extract the olive oil? — 1.8. (Blenheim). The feasibility of growing olive trees for their fruit is a dubious one as our dianite is generally not consistently warm enough although the trees themselves are hardy enough to thrive. It takes 25-30 years for the trees to attain full size but only 5-6 years for them to produce their first paying crop where conditions suit them. An oil extraction method is as follows: The fruit is dried as soon as it is glathered in and turned daily. It is then crushed between corrugated rollers which disintegrate the fruit without

breaking this pits. After the fruit has been paj.lped following pressing, it is Jiround, then pressed again. The; liquid thus obtained consists of itoil, water. and various impurities.' The oil comes to the top if the- liquid i? allowed to settle. Foiyowing skimming and screening to clear it perfect clarification u} only obtained by several successive settlings and decantings. t

What method is best employed iln order to confine or restrict : the growth of grass edging d>n to a concrete path? Is it advisable to keep the grass firom the concrete by cutting a small trench between it and tlbe path, or what? it seems :to difficult to keep tidy. — J.T. fChristchurch). Personal preference is for allowing* the lawn to grow right up to ts.e concrete edge. It can be kept, neat and tidy by regularly running a disc type lawn edging itool along the concrete edge. This method relies on a good even finish of the concrete to faci’lf.t.ate the cutting action of the revolving blade. This style is consi'Jiiered easier to maintain and lw>ks better than a trench forniied between grass and path.

Hiow does one stop walnuts from turning black on the tre e? This tree is a big one and usutslly has lots of walnuts but always some go black even when they are still green. — "Wasteful" (Christchurch). Th,: problem of walnuts blackening is due to the rather prevalent disease of bacterial blight. Bordeaux mixture is the prescribed control and two to three spra j "ings are necessary at arow id flowering time to achieve this. However it Is a virtual impossibility to deal with a large tree, in this way and as there is no ! other effective method of conlirol one can only hope that not I too many of the nuts become info eted.