Am I killing my French beans with washing up liquid or is it something else?

[PorridgeAgainAbney]

They were doing so well a week ago, then I noticed lots of green and black fly, so have been spraying with washing up liquid for the past 3 days. Now they are looking very sorry for themselves.

Is it the washing up liquid? It's ecover so it doesn't seem to be as 'filmy' as when I've used fairy. Could it be that? (It is in a bottle that had the cleaning spray in it but I did rinse it first ). Should I buy a 'normal' one that will leave more of an oily film on? There are definitely less flies on it now, and there is new growth coming from the middle but they just look a bit droopy, and the leaves are a bit dry and mottled.

Or do you think it's another disease that's the problem? Or just the fact that it's colder/windier this week? I'm still taking them indoors at night.

Are you in an area where there may have been a frost during the night? We got a brief frost one night recently and it set some of my beans back.

No it hasn't been cold and I've been taking them in at anout 9pm then putting them back out around 8am. There was a really windy day this week, but I'm thinking I've maybe used too much washing up liquid on the flies as when I watered them this morning there was a whole layer of bubbles on the soil ?!

I think you could be using too much washing up liquid and it might’ve building up on the leaves. Try watering them with clear water and see if that helps.

You will only need a tiny drop of wul

I assume you are diluting it with water?

A cold wind can do that - the leaves are incredibly tender

I am diluting it but I think because it was staying very runny and looked like it was just pouring straight off I added more. Probably about the amount you'd use to wash up in maybe 200-300ml water. I've been a bit dim haven't I?

Mine did that at the same stage of growth about a month ago. Those leaves stayed droopy and mottled but they are taller now with lots more healthy growth and beans on! I'd just persevere.

This is from an American site but it's still relevant to the UK: laidbackgardener.blog/2019/12/08/garden-myth-dishwashing-liquid-as-an-insecticide/. Wash the insects off with a hose, supporting the leaves and stem with the other hand. Much better than detergent.

Thanks for all your input. I'll water with clear water again and see how they go with much less washing up liquid if the flies come back.

I'm going to plant them out this weekend so I'll put some canes up with fleece barrier around too as it gets quite windy (hillside garden) so maybe that will protect the plants a bit too.

Interesting Swanee. I wanted to get some of that but haven't been able to get to a garden centre so was using the ecover to tide me over until the weekend! I will get some tomorrow morning and hopefully my beans will forgive me .

The idea behind the washing up liquid spray is that the greenfly and blackfly breathe through holes in their skin, so you basically drown them, with a bit of washing up liquid to improve the wetting capability. There's no benefit in leaving a residue of dried up washing up liquid on the plant - it won't affect later arrivals.

I'd have though with seedlings that size it would be more effective simply to run each one under the tap and simply wash the aphids off.

I'm curious, though, as to how you managed to get enough of an infestation as to be problematical. My experiences is that the seedlings are not particularly attractive to aphids.

I personally have a hard time believing washing up liquid is as safe as it’s made out to be.

I think that massive pest infestations are indicative of imbalance and given time and enough plant diversity will fix itself.

Organic or non organic, ‘safe’ or not, I don’t think it’s wise long term to go spraying this or spraying that to get rid of aphids or ants or slugs whatever.

In my front garden, I have a huge variety of plants and very, very little trouble with pests.
Yes I do get some leaf damage from slugs/snails and things and I find clusters of aphids etc on certain plants but never out of control infestations, nothing ever seems to seriously damage any of the plants.

The back garden is a different story.
Both gardens are quite large and it takes a long time to get them where i want them because of time and money.

Unlike the front, the back doesn’t yet have a big diversity of plants and it’s overrun with ants and slugs/snails.

I can plant things like hostas in the front and they’ll survive, but they’d be eaten in a day in the back.

I would use plain water to wash off your aphids then I’d plant them outside but underplant them with either nasturtiums (to attract aphids instead of the beans) or garlic (to repel them)

The trouble with using washing up liquid is that it harms the good insects as well, try making up a garlic spray instead and see how you go with that, there are loads of recipes on Google. I walk around my garden and hunt out ladybirds or their lavae and put them on anything with greenfly on and they munch them or you could squash them(the greenfly) with your fingers.

you could squash them(the greenfly) with your fingers. That's not as revolting as it sounds. They're mainly water.