Gardeners' queries

Press, 23 July 1976, Page 8

Gardeners' queries

Last season * a wellestablished grape vine trained over a sunny position cropped poorly. Only about 25 per cent of the fruit swelled, leaving pin sized grapes on uneven bunches. The position, next to a drive way allows for only a small strip of ground from which the. roots can be fed, and this is never allowed to be dry. How could another poor crop be avoided? Also the vines of our two Chinese gooseberries are growing entwined in netting and it looks as though severe pruning will be necessary. More of the male vines appear to need this. On a percentage basis how much more female than male vines need to be left to ensure a good crop?—F.H. (Christchurch).

Female plants are the only ones to bear fruit, provided that they receive adequate fertilisation from a nearby male vine. This is an essential for the successful fruiting of Chinese gooseberries. The ratio male to female flowers is not known but obviously the more female there are the greater the fruiting potential, in the field, recommendations are to provide one male plant for every seven female ones. The ’ rampant natural growth habit of these plants makes it absolutely essential to commence with training them right from the time when they are first planted. If this is not done then they rapidly ! become unmanageable and less 'and less productive. The probItem with the grapes is not so easily answered as there are several possible reasons for the occurence mentioned and without seeing it creates a problem in itself. Boron deficiency is one possibility and as such has been successfully remedied bv the application of 60g borax per vine every five years. Virus infection can cause similar symptoms to those mentioned but for this there is as yet no remedy. Grapes do not require very much feeding nor do they require excessive watering at any time.

Can all seasons oil be mixed with malathion or lindane? (2) Is captan compatible with other sprays? (3) We put on a spray of all seasons oil, winter strength, to deciduous fruit, and ornamental trees, but I would be glad to know if a spray of lime sulphur now — a month later — would be beneficial to apple, grapes, etc., as well? (4) Would you tell us just how to pit carrots? We have sand. (5) In trying to form a frontage of shrubs we have planted a prostranthera next to an incense cedar, and then a breath of heaven beyond that. I feel that perhaps we have planted a moisture loving tree between two that prefer it drier? (6) We have a seedling kowhai which is about 15 years old, but it has never flowered. Could you suggest a reason? — E.W. (Christchurch).

(1) Malathion and lindane are compatible with all seasons oil. (2) Captan is incompatible with lime sulphur and all spraying oils. Also, combinations with emulsifiable concentrates is not recommended. (3) It would be preferable to apply the lime sulphur at the fully dormant stage and. if need be. use the oil at bud movement at a weaker strength. (4'i Carrots intended for storage should be not allowed to dry out but should be pitted or whatever alternative form of keeping Is intended as soon after lifting as possible. A cold sunless position will do but not one likely to receive more than a few degrees of frost. A scm layer of sand should precede the first layer of carrots followed by another layer of sand and so on. Alternatively, the carrots can be stored in sandfilled receptacles of some sort. (5) Libocedrus decurens, incense cedar, has no particular affinity for moisture and as such can be left to grow with the other shrubs. (6) The smallleafed kowhai to which you are probably referring to Sophora microphvila. mav take as long as 20 years before it comes into flower, more or less when it sheds its juvenile form. There is no known method of hastening the onset of flowering with this species.

For some years I have been trying to grow carrots but without success. My garden soil is good friable loam with compost. It grows good brassicas, so does this mean that the soil lacks something for root vegetables? My carrots grow only about 3-4 inches and the leaves have a reddish tinge. — J.M. (Christchurch). The answer to this question could lie in the information supplied bv the last sentence above. The reddish discolouration of the carrot tops is due to a virus infection called “Motley Dwarf.” This disease can seriously disrupt growth and very little root is produced as a consequence. The virus is spread by the carrot aphid and is mainly carried to the crops between September and November. Early control js therefore desirable and the application of menazon is recommended. Further, the reference to the use of compost — this should not be applied before the sowing of carrots unless it is completely broken down as it usually restricts the natural development of the roots. It can, however, be fully recommended for brassicas, which generally respond to a more alkaline soil.