Picture of Medwyn Williams

Medwyn Williams

Hello. I'm Medwyn Williams – eleven times Gold medal winner at the Chelsea Flower Show, Past Chairman of the Royal Horticultural Society Fruit Vegetable and Herb Committee and President of the National Vegetable Society.

Carrot Fly – Protection


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!

Long Carrots and Parsnips in grey pipes on land
Long Carrots and Parsnips in grey pipes on land

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.

Carrot bed coverd over with mesh on plastic hoops
Carrot bed coverd over with mesh on plastic hoops

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.

Mesh tied down to hoops with thin rustproof wire
Mesh tied down to hoops with thin rustproof wire

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.

Nematodes in packet taht was kept in the fridge until required
Nematodes in packet taht was kept in the fridge until required

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.



Growing Parsnips

25th July 2007 I am often asked what is the best method of growing both long carrots and parsnips for the show

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10 thoughts on “Carrot Fly – Protection

  1. I’ve written to Garden News twice asking them to stop printing that nonsense about carrot fly only being able to fly a few inches off the ground Medwyn, once when Bob Flowerdew wrote it and again when Nigel Colborn did but both times they failed to print my letter. Presumably they didn’t want their esteemed writers to look as if they were in the wrong. I was very polite(ish) both times as well!

    I think Monty Don has even said the same on GW on the telly!

    1. Hi Simon,
      I can only think neither of them have ever grown any decent carrots then! Trust your grandson is coming along fine now,

  2. Yes thank you Medwyn. Touch wood (my head!) no more seizures since he’s been on daily medication. Just had a week away on holiday with him and his mum and I’m shattered, he’s really worn me out!

    Pretty excited so far with your Victor parsnips i’m growing for the first time this season. I was surprised at how small the seed was but it hasn’t made any difference. Really strong growth and the foliage seems a darker green than any other parsnip i’ve ever grown.

    1. I Have had some really positive comments from many growers regarding the parsnip Victor that I introduced last year. Having won the Welsh Championships with it at Wrexham , perhaps I should have kept the seed to myself!! I would love to hear from other growers who are growing it also its sister variety Viper. Viper is a slightly later developing cultivar and I’m growing both this year for my Display at Malvern.

  3. Hi Medwyn,

    I’m also growing Victor this year and as I said on the phone the other day, so far these look very promising indeed. If underneath is as good as the foliage then they could be fantastic.

    Glad to hear your Grandson’s doing well Simon 🙂

    1. Knowing how capable you are at growing Parsnips when you showed a lovely set of Panorama on your collection at the Welsh Championships last year in Wrexham. I think you will find that Victor will have a much more refined body, white in colour and carrying it’s weight straight down from the shoulder without ‘waisting’ at all. Good luck when you come to pull them and don’t swear at me if they’re forked!!

  4. Forked parsnips will be the least of Marcus’s worries at Dundee Medwyn, as he’s asked me to stage his veg for him due to the restraining order and electronic tag meaning he can’t leave the Midlands I think. I have some very creative ideas for presenting his veg if it’s any good…..mostly involving leaving them in boxes under the staging!!

    1. Hi Simon, Parsnips need to be as uniform as possible with the length to be in balance with the girth of the shoulder, I suggest you therefore take a knife and cut them all to exactly 12 inches in length before staging them for Marcus, he has a good chance then of getting maximum points for Uniformity!!. Seriously though, I was talking to Ian Stocks yesterday and he believes that his Victor parsnips are the best he’s ever grown and he’s staged some good ones in his time. Should be some good entries at Dundee, let’s hope there’s some decent judges up there!!

  5. Oy you two… 🙂

    I doubt if i’ll be sending parsnips to Dundee, only stuff that’s easy to carry and stage as John B is kindly taking anything I have with him for Simon to stage. You never know though.

    Hope to put a lot of entries in to the Welsh and Malvern this year, i’m growing 16 Victor for each of them. Looking for a 1st in a collection this year… 🙂

    You going to the Welsh/Malvern this year Simon?

  6. Dundee, Malvern and Westminster all being well Marcus. But much can change!

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