Page 31 - ALG Issue 4 2014 Digital Edition

Regulars Q
ike Thurlow... &MA
I have tried to select questions that may be
topical and cover most aspects of the vegetable garden/allotment. Allotment gardening covers a wide range of interests; if you want to include any other
areas of gardening please send your questions in.
Carrot fly protection
Q. Protection against carrot fly and cabbage root fly
Can you advise on where and what to
width netting with a mesh of 1.3mm x 1.3mm. I always throw the netting over
1 metre high supporting stakes to form a tent or cage. You will need enough width to make sides and a top. The netting doesn’t have any colour; it is made from an opaque material to reduce light reduction. Green netting would create shady growing conditions and produce weak, drawn plants.
purchase for protection against carrot fly and cabbage root fly. Is 2mm mesh size right or does it need to be smaller? I have a large veg garden and need it in 20m lengths. What is the most manageable size, 1m or 2m width (bearing in mind it will be used also to keep caterpillars off the purple sprouting and other cabbages as well)? I have had a look around the internet and veggie mesh looked good but I would
Crop rotation
Q. How do you effectively carry out crop rotation? I am lead to believe you are supposed to plant the next year’s crop
to complement (nutrients etc.) what was planted the year before. Michael
A. Crop rotations are also used to
smaller mesh because it damages the wings of the carrot and root fly as they try and push their way through the net.
You can buy the netting from LBS via telephone – 01282 873370 or go to their website – www.lbsgardenwarehouse.co.uk. for more details.
They manufacture the whitefly netting in a 2m width with a mesh size of 0.22mm x 0.8mm and the cabbage root fly in 2.1m
prefer green colour. Many thanks for any help. Paddy Matthews
. I would always recommend using a
A
reduce the risk of crop specific harmful plant pests and diseases building up to damaging levels in the soil. They are an important way of disrupting the life cycles
of these pests and diseases and it prevents them getting out of control. The most common rotation system used is; legumes (peas and beans) followed by brassicas that are followed by others (potatoes) followed by roots (carrot family and onion family). The legumes fix nitrogen on their roots which benefits leafy crops like the brassicas and any well-rotted organic material (compost or manure) that is added to the potato bed is well broken down. This should be done before it is followed by the carrots and parsnips that require a well dug soil but don’t appreciate fresh manure because it will cause their roots to split or fork. After a couple of seasons of using the rotations the soil will be in good condition and its fertility can be “topped up” using pelleted poultry manure or green manures.
Club root
Q
A
. It’s many years since Calomel Dust was banned for use to prevent club root. Any
suggestions for a replacement would be welcome. Ray Todd
. Club root is a major problem on allotments everywhere. It is usually an inherited
problem generally as the result of the cultivation techniques of previous tenants over the years. Club root (Plasmodiophora brassicae) is a slime mould that can survive as resting spores in the soil for up to 20 years. So you can appreciate that your soil could have been infected as far back as 1994 at the latest!
Calomel dust or paste contained mercurous chloride that was used in the manufacture of brassica club root control products. All calomel-based products were banned from use in the U.K. in 1991 because mercurous chloride was recognised as being a poisonous chemical.
There aren’t any chemicals to control club root available to the amateur gardener at present.
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