Thursday, June 29, 2006

Fight the Blight.................

I went down to the plot today to dig up some more new potatoes, and noticed that the second row of earlies, and the main crop are both just about to start flowering. This is the time then to start piling on the water. So I did.

I read on someone else's blog the other day that "you should never water onions & potatoes" which seems strange, but I can't find the entry now. Potatoes need lots of water to yield a good crop, and the time to start is when the very first flowers appear. Dr Hessayon says "Water liberally in dry weather - This is most important once tubers have started to form." Commercial growers usually work to the rate of 2 gallons per square yard, and will apply this regularly in hot conditions.

One of the reasons why some folk are cautious about watering their 'taters, is that the prime watering time of mid June to mid August, is also the dreaded potato blight season, and this most devastating disease thrives in hot humid conditions.

The best way to avoid blight is by knowing how it is spread. The following is good practice, and was explained by Stefan Buczacki on his Garden Questions program on one of the cable channels today....( See - daytime TV can be good for you!)

1. Contrary to many people's belief, blight does not live in the soil. It is a fungal strain, who spores are borne on the wind over long distances.

2. The spores lands on the leaves, and will remain there in very dry weather. They cannot "travel" through the plant, but require rain (or watering) to wash them down the stems into the soil, where they attack the tubers. Therefore hot rainy summers will almost always result in various degrees of blight on intensively cultivated allotments. New potatoes will probably harvested by then, but main and late crops can be ruined if left unchecked. Although you can now get quite a few good blight resistant varieties.

3. Now you know how the spores reach the spuds, make sure that when you water, you keep the hose or watering can nozzle right down at the base of the stems, at ground level, and water each plant individually. This way you will avoid washing spores down the plant as much as possible. If using a hose, take the pressure jet off the end to eliminate too much spray.

4. If you do get an attack of blight, as soon as you see the leaves turning a sickly yellow and black, (this is very rapid as opposed to natural dying off) immediately cutting the helms right down to ground level may well save the crop underneath. Burn any infected material, or bag it up for disposal off the site.

5. Although it can't live in open soil, blight will remain in any stray tubers, so make sure when lifting the crop, that you remove every last little one....And don't throw them on the dump....take them off site and bin them. Re-infection from last year's compost heap is one of the most common sources of the disease.

But certainly don't let the fear of blight stop you from watering your spuds....(Sounds like a euphemism for something rude... Ed.)


Blogger Rebsie Fairholm said...

Having just got in from giving my spuds a good soaking I thought I'd reply to your post.

I'm all for watering potatoes, otherwise you end up with much smaller yields. So bung it on, I say.

But I think your point no.3 is spot on. Watering very low down so that you don't splosh it all over the leaves is a good idea. It helps to avoid creating a humid environment around the plants. And it also acts as damage limitation ... if there are invisible blight spores on the leaves it makes them less likely to be washed down into the tubers. So in the event of the haulms being attacked you may still be able to salvage the spuds.

I use sawn-off Ribena bottles stuck in the ground to get the water directly to the tubers (similar to your bucket system) but nothing works 100% ... it's all down to vigilance and luck.


11:48 am  
Blogger Greenmantle said...

It certainly is down to luck in large measures...Unlike your singing which is a thing of skill and great beauty...I have been checking it out lots.


12:16 pm  
Blogger hellyplot said...

Also got back from my plot this morning and wish I had read your blog before I went. Do water a lot once flowers appear however, have not been doing point three have been sploshing all over whoops, relatively new to this only took plot on in Hastings last year. Will do better from now on. Thank you.

9:29 am  
Blogger Allotment Lady said...


Great advice for newbies and lovley photos - you are really doing well.

As you know there is not chance of me watering my 330ft long allotment -so the potatoes have to take their chances along with the onions. Where I live is one of the driest counties in the UK and we are really suffering this year. I totally agree with blight resistant varieties and grow them myself - but some do not have the same taste or texture as the good old favourites - so I usually grow one variety that is not!

My new potatoes are yielding an average of almost 3lb per plant - with hardly and rain and no watering - and they taste wonderful. The wilting leaves I cut down to save water evaporation. It is working for me with my new potatoes, but am not doing it with my mids or lates and that would be fatal.

The onions are doing well, again, despite no water.

The only thing I water two or three times a week, and sparingly, are the tomatoes (71) and my pumpkins and squash.

The very best thing you can do in an area such as ours is to really look after your soil - plenty of well rotted manure - really makes a difference. I am convinced that my crops would not grow without it - and I know this by looking at neighbouring plots that do not take care of their soil!

Keep up the great work - you are doing a grand job

9:11 pm  
Blogger Greenmantle said...

This comment has been removed by a blog administrator.

9:30 am  
Blogger Greenmantle said...

How I envy you your 71 tomato plants Al!

I can't grow them succesfully here. They get blight and rot every year, before they are ready to harvest.

I'm not getting 3lb a plant on my spuds either.

9:31 am  
Blogger Rebsie Fairholm said...

Aww, thanks for your nice comments about my music! It means a lot to me that you checked it out.


12:35 pm  

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