Topic: bordeaux mixture - when to apply

[misterphil]

I was reading that Bx mix can be used as a preventative for potato/tomato blight and for mildew on fruit bushes ... but when should I apply it? To the ground before planting? on new growth?

Any ideas welcome, as I was hit hard by blight last year

Thanks

[jennym]

Well, only ever used it on tomatoes. Sprayed it on 1st August, and again on 14th August. The blight normally hits our site from mid August onwards, so you'd have to adjust dates to suit your circumstances. It is most effective when it doesn't get washed off by rain. I believe the harvest interval is 7 days, i.e. you should harvest the fruits for 7 days after application, but you would need to check on this.

Modified:
Just checked, and it is approved for use as a fungicide only on :apple, blackcurrant, celery, cherry, gooseberry, peach, plum, potato, tomato.
Safety data sheet: http://www.vitax.co.uk/home-cat/safety/HOM025.doc
This gives the timing for peaches : http://www.rhs.org.uk/advice/profiles1200/peach_leaf_curl.asp

[tim]

Probably repeating previous but:

On potatoes - on foliage from June onwards - depending - & before foliage closes over rows - under & over. Esp in warm, damp weather. Every 2-3 weeks. No harvest limit if haulms are cut. With new pots - take care?

On toms - from July - depending- every 3 weeks.

[sandersj89]

And for an indication of when Blight may be due and what weather conditions are conducive to blight development have a look here:

http://www.potatocrop.com/blight/blightabout.asp

You can sign up for a free service that will email you when a "Smith" period has been met in your local area and you can then spray it you so wish.

This is a service aimed at commercial growers but it is free and I have been using it for a few years now.

It is also a good record of max and min temperatures for your area that may be of interest.

HTH

jerry

[Curryandchips]

Just as an aside, I note that bordeaux mixture contains copper sulphate as an active ingredient, which is known to be toxic (even going back to my school chemistry days). I would not feel comfortable spraying this onto tomatoes or other fruit that could be eaten straight off the plant, as I often do when on the allotment.

[tim]

Agree, in general, but  as you have to do with flowering trusses, you can cover the fruiting trusses when spraying. It all depends upon whether you want fruit or not?

[Robert_Brenchley]

It's certainly poisonous in large quantities; I completely cleared the garden of bindweed when I was a kid (it had been overrrun) by nicking some copper sulphate from the chemistry lab at school, making a concentrated solution, and repeatedly painting it onto the leaves. They never came back. But bordeaux mixture is diulte, and I don't know of anything non-poisonous which discourages blight as effectively. I don't use it though.

[tim]

It's still accepted as marginally 'organic'?

[Doris_Pinks]

I am afraid that this year I am joining the Bordeaux club, wish it was a wine one!!
After loosing all my tommies to blight for the past 5 years I am biting the bullet and giving it a go, I even got blight in my greenhouse!

So demoralising to loose those plants you have nurtured for all those months, so I guess I shall be a nearly Organic gardener this year :(
DP

[sandersj89]

Doris

Have a look at the blight "Resistant" varieties of toms, Ferline and Legend. I grew Ferline last year and will do this year. In fact we are still using them either from the freezer or dried.

They were very very good and on our site I was the only person to pick outdoor toms in August through to October. Every one else had horrid blight problems.

I also grew San marzona and Sungold outdoors and both these succumbed. The ferline grown within feet of the others was fine.

Jerry

[OllieC]

Hi all - new to here but have been reading posts for a while and gardnin' for longer.... Bordeaux mixture is fantastic stuff. After all, 10 Million French peasants can't be wrong.
Okay, they could be incredibly wrong and would probably notice if they stopped drinking for long enough to notice. But it's the only way I've ever managed to keep blight off my toms (I spray weekly from first fruit onwards although prob. don't need for the last month). It rubs or rinses off, and is not absorbed into the fruit. And as already said, is marginally organic (I heard the Soil Association are removing it this year or next?).

I use a sprayer rather than dusting it.

[Curryandchips]

Just to clarify, my comments on Bordeaux mixture were meant to be just that, an observation, not a criticism or a slur on anyone who uses it. Whilst I recognise it is a toxic material, the level of toxicity could well be masked by the chemicals that get brought out of the sky when it rains. I garden naturally, not organically, because of the fastidious manner which can become necessary (again no criticism aimed at anyone who does do this) and accept that certain materials do become necessary. If I suffer the massive losses that some of you appear to, then I do accept that my view could be changed.

At the moment, I delight in eating tomatoes straight off the plant, believing that there are no known nasties going into my mouth. The suspicion of copper sulphate being on the skins would mar my enjoyment - that is all  :)

[tim]

I, for one, would wholly agree with that.  Didn't notice a slur!!

[Doris_Pinks]

Jerry even my Ferlines sucumbed last year! (think on my plot it has a lot to do with the fact I back onto the communial compost heap! I seem to get everyone elses nasties)

Curry I quite agree with you too, gonna be hard for me to spray em, thought I would try some with and some without! and am going to try and rig up some protection for them ;)

Tis all a great learning curve this gardening lark! ;D