DIY brassica collars

[Clara]

just wondering if anyone had made their own (I bought some biodegradable ones last year), and what did you make them out of? I've seen it recommended to make them out of old carpet, but that's not something I'm gonna find around here (tile floors). I have cardboard in abundance, would that work?

[Odsox]

I make my own but you have to be a certain type of person to copy my solution.
I use the plastic lids from the tins of espresso coffee they sell in Lidls. They are about 9cm in diameter and fairly soft plastic.
I get through about one tin a week, so 50 a year is just about right.

[Annpan]

Two questions.... excuse my ignorance....

What is the benifit of brassica collors?

Would the central section of a tetra-pak do the trick?


I know that doesn't help you out Clara... sorry

[Odsox]

Brassica collar are the ONLY way to stop cabbage root fly.
Sorry, no idea what a Tetra-pak looks like.
One out of two ain't bad

[Annpan]

Tetra-pak is the plastic coated juice cartons that fresh juice and smoothies come in - most councils won't recycle them (and since we don't have a re-cycling collection at all) we try to re use them a till they fall apart, before sending them to landfill.

[contadina]

I'd use pretty thick cardboard Clara - we used thin stuff one year and most blew away, or use pebbles to keep it in place. I've tried cutting up and old bobbly cardigan which worked quite well. As it was fibre watering was not an issue and it was thick enough not to disintegrate.

[Clara]

I make my own but you have to be a certain type of person to copy my solution.
I use the plastic lids from the tins of espresso coffee they sell in Lidls. They are about 9cm in diameter and fairly soft plastic.
I get through about one tin a week, so 50 a year is just about right.

I get Marigold stock and I think I could use the lid of that - it always annoys me how completely and utterly unrecyclable the packaging of that is, at least I will have a use for part of it in future. Though it'll be a few years before I'm using them exclusively! I'll have a scout round and see if there's anything similar I use. Top tip, thanks

We get through a tetrapack a day so that's a goer for now, nice one AnnPan. BTW I have no idea whether they prevented root fly or not, I just didn't take any chances with my brassicas last year, so don't know if I'd left them alone whether they'd have suffered anyhow, but it is the stem rocking in the wind which can create a gap around the bottom of the plant for the little buggers to get in, seeing as I'd planted mine in a fairly windy place I thought I'd better take precautions.

[Odsox]

I just didn't take any chances with my brassicas last year, so don't know if I'd left them alone whether they'd have suffered anyhow, but it is the stem rocking in the wind which can create a gap around the bottom of the plant for the little buggers to get in, seeing as I'd planted mine in a fairly windy place I thought I'd better take precautions.

As far as I know (or should I have said AFAIK ), it doesn't matter if there's a gap or not. If you live in an area where root flies are active ALL brassicas are at risk.
The female cabbage root fly finds suitable brassica plants and then lays her eggs on the ground within a cm or so from the stem.
When the eggs hatch the grubs burrow down and eat the roots which kills or severely disables the plant.
If you use collars it not only creates a physical barrier but also can dry out the eggs so that they may not even hatch in the first place.

[Millymollymandy]

I must be lucky as I've never come across this insect. Do you use these things for curly kale and purple sprouting brocolli, or is it only cabbage that gets attacked? And how do you put it round radishes and rocket?

[Odsox]

Wow, you are extremely lucky MMM, although I moved from an area where Pea Moth is devastating to here where there is none.
Not much you can do about Pea Moth but you can stop Root Fly 100%.
Can't speak for Radish or Rocket as I don't grow them, but I have never had the problem with Lettuce.
Worst affected crops are all cabbages, sprouts, cauliflower, calabrese & PSB. Don't remember having a problem with Russian Kale much but don't know about other Kales.

It's heartbreaking if you do get it, the first sign is apparently healthy plants wilt in the midday sun only to recover by the next morning. Then after a few days they just wilt and die.
When you pull them up you will find no roots left and a load of very healthy white grubs, very similar to Vine Weevil.
They can even find brassicas in the centre of a polytunnel too.

[Millymollymandy]

Lettuce isn't a brassica by the way!

My PSB is practically dead because after all the seriously cold weather the last few weeks - guess what, yes the blackfly is still alive and partying on my plants!

I wonder what you do though with these collars as the plants grow? E.g. my PSB was tiny when I planted it but now has a stem about 2" across.

Anyway I'm not lucky as I have many other horrors to contend with like flea beetle which loves brassicas!

[Odsox]

Lettuce isn't a brassica by the way!

I stand corrected

You cut a cross in the centre of the collar so that it expands with the growing stem, but you didn't need to know that you lucky thing.

[Millymollymandy]

Right OK! I was wondering whether my 'luck' is because I don't plant out any brassicas (not even sow radishes) until at least mid August - that's cos of the flea beetle problem earlier in the summer. If not then I will thank my lucky stars because I have enough problems in the veg patch!