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Produce => Edible Plants => Topic started by: sawfish on July 09, 2007, 19:53:44

Title: Onions dying
Post by: sawfish on July 09, 2007, 19:53:44
Loads of my onions especially the red ones seem to be dying. The tips of the top shoots are drooping and turning brown plus they seem to have stopped growing.

any ideas?
Title: Re: Onions dying
Post by: Robert_Brenchley on July 09, 2007, 19:59:20
lift one and see what's underneath.
Title: Re: Onions dying
Post by: Tee Gee on July 09, 2007, 20:41:45
Do they look like this............mildew!!.............lot of it about!!

(http://tinyurl.com/2xzh4y)
Title: Re: Onions dying
Post by: mc55 on July 09, 2007, 21:30:51
oh dear, mine look exactly like this.  Should the be left in the ground or lifted ASAP ?  Is there any cure ?
Title: Re: Onions dying
Post by: Eristic on July 09, 2007, 23:46:33
I would like to run my hypothesis past Tee Gee and others regarding this situation.

This year so far has produced the largest population of slugs I have seen in all my life and this coupled to the rained out June has caused the problem.

First, the slugs graze on the onion leaves eating the outer layers of skin including the natural bloom which I believe to be a natural defence against airborne diseases. The leaves in Tee Gees photo definitely show signs of this grazing and mine were far worse.

Second, the constantly wet conditions coupled to the slime residue of the slug allowed fungal spores to easily adhere to the foliage and rapidly develop into a serious debilitation of the onion.

Third, the efforts to combat weeds and pests have compacted the wet soil hindering good growth. In my situation, the incessant attack from the slugs finally ate all the leaves right back to the neck in spite of me removing between 1 and 2 litres of slugs each evening.

This combination of events has led to pathetic yields of onions for this season. The mildew does not seem to affect the quality of the bulb itself but without lots of healthy foliage, the size of the onion is greatly diminished.

Mc55. If the onions still has a healthy leaf or two growing from the centre, I would leave them to develop further otherwise you may as well harvest what is there.
Title: Re: Onions dying
Post by: miniroots on July 10, 2007, 09:23:01
Given that I can't believe I haven't got mildew!  Maybe red onions are more resistant?  But then they are more susceptible to bolting, which they all have - bar one!
Title: Re: Onions dying
Post by: Tee Gee on July 10, 2007, 12:58:37
QuoteThis year so far has produced the largest population of slugs I have seen in all my life and this coupled to the rained out June has caused the problem.

I agree entirely plus lest we forget, we had a mild winter so the egg population was allowed to survive in greater quantities.

I have asked my wife and kids for two months of hard frost as a christmas present this year ;D

Quotenatural bloom which I believe to be a natural defence against airborne diseases.

Never looked at it in that way but it is feasible.

Regarding the slug trails not sure on that one but it certainly wouldn't have helped. Although I agree on your comment on wet conditions.

How I look at it is the mildew spores are borne in the wind and will stick to wet surfaces. This is one reason (in normal seasons) I don't use a hose i.e. I don't want to wet the plants only the soil around the base.

QuoteThird, the efforts to combat weeds and pests have compacted the wet soil hindering good growth.

Don't have that problem!! hip! hip! hooray! would you believe it I have found something that wasn't a problem this year.  ;D

Seriously though my 'bed' system alleviates that but as I mentioned in a previous post my neighbours weeds may have caused me problems.

Quotein spite of me removing between 1 and 2 litres of slugs each evening.

This is one reason I am not a totally organic gardener. There comes a time when you have to make a stand is it the plant or the pest that survives? this time I chose that the plant should survive and I used slug pellets.

QuoteThis combination of events has led to pathetic yields of onions for this season. The mildew does not seem to affect the quality of the bulb itself but without lots of healthy foliage, the size of the onion is greatly diminished.

Agreed!!

QuoteMc55. If the onions still has a healthy leaf or two growing from the centre, I would leave them to develop further otherwise you may as well harvest what is there.

I would just remove the worst affected leaves after all they are useless to the plant.

If this means removing them all then lift the onion.

Note

The reason I say it is my worst year is not that I won't lift crops

No! its the fact that I don't think I have one crop that has not been affected by one thing or another.

In previous bad years the problems have been specific and only affected some crops not every crop as this year.

Well these are my opinions please comment warts and all. By doing so we might learn something for future from comments made.

As they say two heads are better than one Eristic and I have given our views has anyone else anything to say?
Title: Re: Onions dying
Post by: cornykev on July 10, 2007, 14:56:30
My only question is that I have suffered the slug damage as well, but the foilage seems to be coping, it looks tatty but not dieing away, the onions are lovely purple colour but don't seem to have grown very much, are they just in need of some sun.  8) ;D ;D ;D
Title: Re: Onions dying
Post by: Eristic on July 11, 2007, 01:38:10
My foliage did not die away, it got eaten relentlessly untill there was none left. Normally in June I would expect to get maybe one flowerpot full of slugs each evening for 3-4 days before numbers diminished sufficiently to ignore them for 3-4 days until numbers increased again. Under these conditions the onions outgrow any damage. This year I lost the war and to be honest, I doubt that slug pellets would have saved the day either. I've still got onions but the yield is probably only 20% of normal.

Red onions have fared better than the Stutgarter for some reason.
Title: Re: Onions dying
Post by: polly on July 11, 2007, 10:29:26
Best onion crop ever, this year, from a spring sowing of sets.  Nice fat onions, only at the early stages of tapering off. I reckoin it's a few weeks at least before I lift them, but shallots will be earlier.   

The autumn sowing of sets was far less successful - smaller onions, tops eaten off (rabbits? crows?).    I did (finally) sow the spring ones deeper than I have in the past, and the rain on our very sandy site has probably helped (apologies to those who are waterlogged).

Can't say it all has to do with location/soil, etc, as a friend at the other end of the allotments had exactly the opposite experience - and we had the identical varieties - had bought a large quantity and split them!

Title: Re: Onions dying
Post by: GodfreyRob on July 11, 2007, 10:41:38
First time growing onions in new garden veg patch. Grown on raised beds so most ok - maybe 10% going to seed. I think the going to seed was down to the very warm dry May (can you remeber that!). Both red and standard varieties about the same.
Shallots look good too. Garlic tops starting to go rusty with yellow so I guess they will be ready for lifting soon.