I have had far more problems with carrot fly since I have been growing down on my land than I ever did whilst growing them at home. If you read some of the gardening books they will tell you that the carrot fly won’t fly over a two foot barrier of polythene erected around the carrots. Well I have news for those writers, I must have some powerful carrot flies on the land as the large grey pipes that I grow my long carrots in are at least four feet above the ground and they had the maggots in them for the past couple of years!
The same applied to my Sweet Candle carrots bed as well as the other longer bed with over 400 stations of various coloured carrots as well as some new trial ones, all mainly for my display at Malvern at the end of September. There’s no doubt that the only real solution is to physically prevent them from getting on to the growing area. This year I decided to build a barrier from Enviromesh that is available in my Catalogue under Item 0099. We decided to stock this at a width of 2.6mtrs (8ft 6inches) as it gives good coverage with plenty of height for carrots spanning over a 4ft bed.
The way I have done it is to use two different sizes of commercial stiff blue plastic water pipes with one fitting snugly inside the other. The largest bore was cut up to approx. 18 inches in length and screwed along the side of the block work. The other pipe was cut to sufficient lengths so that I could push both ends into the other pipe whilst at the same time forming a rigid arch over the bed.
The hoops were then screwed together to a batten running the full length of the bed and the mesh was thrown over. The bottom of the mesh has a long steel pipe running along it which I happened to have on the field and this adds weight to the Enviromesh and prevents it flapping round.
The end pieces were cut roughly to the shape of the arch using an electric soldering iron which melts the fine nylon type material as it cuts its way through it thereby preventing any ravelling of the edges. This was then tied to the hoops using some thin wire and a row of bricks was laid along the bottom to seal it all off.
This way I can roll the sides up and fasten them to clips screwed along the top of the batten to allow me access for thinning weeding etc. The same clips are also used alongside the edges of the pipes to keep the Enviromesh in place. These are the white clips that you can buy with the pipe from any builders merchant and are made specifically for screwing to a structure and then snap the pipe into them.
My only concern was that I might have trapped some flies inside the mesh and thereby wasting my time in building the whole thing. To this end I have bought some Nematodes under the name ‘Nemasys’ which offers natural fruit and veg protection.
The packet has a ‘Use before date’ of the 15th July on it and can only be used when the soil temperature (in my case sand temperature) is at least 12°C (54°F) According to the instructions and information on the packet, it controls Cabbage root fly, cutworms, onion fly, sciarid fly, caterpillars, gooseberry sawfly, shore fly, codling moth and most importantly Thrips as well. The sand or soil must be moist before, and for at least two weeks, before application. The pack will fill 4 watering cans and treats up to 60 square metres (70 square yards). I have bought two packs of these at £5.95 each on Amazon and I shall use the first lot next week, let’s hope it does the job.