What's up with my 'cumber?

[DeeBee]

Hi

I have a Telegraph Cucumber which I'm growing in a mini greenhouse outdoors in a large tub. It seems relatively happy, is growing well (I've just pinched out the top as it's as tall as the greenhouse will allow and the side shoots are developing) and I've had a couple of 'cumbers off it already and there are several more growing well. So far so good - except that all of the leaves have white spots - a bit like mould - on them. I can rub the spots off but they just keep coming back. I've read not to water them near to the stalk and so have inserted a pop bottle into the soil and water into that. I try not to over-water, keep the air circulating during the day but close it up at night and feed once a week but still the mouldy spots occur.

If it's just unsightly but not really a problem then I'm not bothered and I'll just leave it but if it's a problem that has to be rectified I'd like to get it sorted, particularly as this is my first year growing my 'cumber and it's done well so far. The mouldy spots haven't spread onto the two tomato plants that are keeping it company but should I move them out?

Many thanks for your help.

DeeBee

[Lesley Jay]

Hi DeeBee, if it is like a dusty mould then it will be powdery mildew. The spores are airbourne and it loves humid conditions like you find in greenhouses - but my plants got it every year on my allotment plots! An organic treatment is to spray the plants with skimmed milk diluted with water one part milk to nine parts water a few times a week. This works because of the salts and amino acids in the milk. The cucumbers shouldn't be affected.

[DeeBee]

Hi Lesley. Thanks for your super quick reply and very reassuring answer to my mouldy problem.

Couple of related queries:

Will semi skimmed milk work in the same way (got a fridge full and can get started straight away) or should I go and buy some skimmed?

Should I move the toms out of the greenhouse of just give them a precautionary spray while I'm spraying the 'cumber?

Have I done anything in particular to cause this or is it a regular occurrence?

Thanks.

[Lesley Jay]

Hi DeeBee, no it's skimmed milk that needs to be used. I don't know if it has got something to do with the fat content of the milk but research has been done across the world and apparently this organic method works.

Powdery mildew is host specific so the powdery mildew that is on your cucumber plant shouldn't affect your tomato plants. The spores will over winter on plant debris and start the disease off again in the spring so it's important to clear up all the plant debris and also don't compost the plant but bag it up for the refuge. You haven't done anything wrong at all - the spores are airbourne, it's just unfortunate that they landed on your cucumber plant.

[DeeBee]

Right, off to the supermarket and skimmed it is then! Many thanks for your help and advice Lesley.

[woodpile]

Thanks Lesley, I know a few natural remedies but I've never heard of that one.

[DeeBee]

Just a thought Lesley - if a plant is suffering from mildew and the foliage has to be destroyed rather than composted, is it OK to still collect the seeds from it, e.g., I've got it on some pansies but have been collecting the seed for next year. Will the seed be contaminated too or are they OK to save?

[Lesley Jay]

Hi DeeBee, powdery mildew is an airbourne fungus that lives on the surface of the plant, it doesn't spread through the plant tissue so the seeds should be fine.