Allotment Gardening Advice Help Chat
Growing => Grow Your Own => Topic started by: Anton on July 19, 2009, 19:56
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My runner beans had a touch of black fly so I went with a mixture of soap (ecovert) and water to spray on them about five o'clock yesterday evening. There was some sun but I didn't think it would do much any harm. Today I see some of the leave are a bit burnt. Right at the top where the plant is curling around the top of the cane the branch is burnt to a crisp. I suppose this was my soap mixture in the sun that did this damage? Could it be anything else (the plants are in flower and a few beans are developing). Will the plants recover?
Anton
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My french beans do this crispy leaf thing if it's been very windy, wind burn i suppose :(
They always seem to recover as long as you water them :)
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I seem to get this when i spray with soapy water (not me my plants)
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Hi
I've not used soapy water as a plant spray before as this gyo hobby is still rather new to me. But I was wondering whether the sunburn is due to the fact that the soap soultion is a surfactant which acts to reduce surface tension (although you were using it here to deter the pests) but then leaves a thin film or residue of soap molecules. This then behaves as a fine magnifying glass and concentrates the rays of sunlight which leaves the leaf surface as if it was under a greenhouse - with consequential increasing surface temperature.
This reminds me of the few occasions when I've got home from work and found the seedlings keeled over on those days when I've left the seed trays outside with the clear lids on and had not expected the weather to be too warm.
Cheers.
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Thanks for the answers. Well, I was surprise that it might be the soap because I do this quite often without any disasters. I think the suggestion that it might be the wind is a big possibility, as it was very windy the day I discovered the "crispy" leaves.
Anton