mesh hole sizes

[bennettsleg]

Re: in Tim's post about cabbage whites.

The respondee states that the CW may lay eggs outside the mesh and the caterpillars crawl through the mesh to the cabbages.

White fly are also a problem as they're _tiny.

Is there a size mesh which is the most effective or can I go the whole hog and use old viole/fine net curtains to protect the plants? The only downside I can think of is less rain penetrating the fabric to get to the plants.

I want to cover my entire bed with a tent of mesh/other next year.

What do yous guys use that you have found effective?

[bennettsleg]

[Squashfan]

Not sure. We've had large mesh on the sides with smaller mesh draped over it, and although the cabbage white still gets in there, no real damage. Only problem we have is with the foxes jumping on top, wheee!  ::) and so the brassicas are growing a bit crooked.

[tim]

I hesitated to come back on that C/W reply - I would have said I doubt it.
Not even a flea-beetle can get through fine mesh.

Size? What for?
1. Finest mesh or fleece for flea-beetle. But this is only necessary "until the plants reach the ? 4th true leaf stage".
2. Less fine mesh or fleece for carrot root fly.
3. Netting or any of the others for C/Ws.

How small a net? No idea, but would suggest not more than 1cm. C/Ws can sidle in along overlapping mesh!!

Voile etc - one disadvantage would be the wet weight? And might not exclude flea-beetle etc.

[Merry Tiller]

Enviromesh or fleece

[tim]

Just to recap -

1. Fleece is light when dry, soggy when wet.
2. It tears easily. But it's cheap.
3. It doesn't  easily allow rain through.
4. You can't see through it.
5. It probably excludes more light than mesh. But it is used in commercial growing?
6. Mesh is always quite heavy. The finer, the heavier.
7. Fine mesh is only needed in the early stages of growth against flea-beetle.
8. You can see through it - more with the more open weave on the right. See below.
9. Mesh will outlast fleece by miles.
10. It is very permeable. Voile & fleece not so.
11. Fine mesh has been known to encourage mould in later growth.

As mentioned, a much coarser net would probably work against C/W.