Otherwise healthy cucumber plant leaves yellowing?

Hello all

In my greenhouse I'm growing tomatoes and cucumbers primarily. This year growth has been a bit slow, but the plants look healthy generally and some small cucumber fruits have appeared. However two of the plants have some sudden yellowing on large leaves, which I'd like help identifying.

I'm thinking over or under watering is possible, but so is leaf burn. My children sometimes water for me and it's possible they've splashed the leaves. I have also used some liquid fertiliser once a week, and more recently some dry chicken manure.

Any thoughts? Thanks!

 

I think it might be leaf scorch, is the greenhouse shaded at all.
Cues are not great with bright sunlight.

 

If it's just a couple of leaves I wouldn't be too concerned.
Splashing water on leaves doesn't cause burn marks on leaves if the sun is out, so no need to worry about that.

I just wonder if maybe you're overdoing the feed a bit?
I feed mine once a week with an all purpose plant feed - either miracle gro, or phostrogen and every 2-3 weeks they get a seaweed drench in place of one of the usual feeds.
Tomato feed is fine for them too, once a week.

 

Thanks. I'm relieved if it's just burn, which is what I was hoping. There's no shade at all that side of the greenhouse no. I can be more careful with watering.

 

Thanks. I may be misreading sorry but do you mean you think it's not leaf burn from splashing?

I was thinking I may have overdone with the chicken manure. I only threw it down because I'd run out of the liquid feed but I possibly put too much.

 

I'm not thinking its splashing, I'm just thinking the leaf has got sunburn.

 

So do I
It's not caused by splashing water

 

I agree too - it's a myth about the water splashing, but it's very easy for foliage to get sunburnt.

You'll often see the scorching with young plants in late winter/early spring if you have them on a sunny windowsill. It doesn't take much for them to get really fried. It's just a later, slightly bigger version of that when you get it in a greenhouse, but some yellowing leaves aren't always a huge problem either if the plants are doing well other than that.

I'd also agree about the amount of food. It isn't always vital to feed a lot, especially if the soil is healthy.

 

Thanks all. So no need to shade the plants as long as they recover OK? They are all starting to look a bit sunburnt after today, tbh, which was really sunny, but heavy rain is on the way.

Final question: if I have over fed, is there any way to mitigate?

Thanks
Jack

 

Usually if plants are overfed they look 'wrong'
There may be extremely dark leaves or what looks like crispy burn marks on leaf edges.
If they're seriously overfed the plant will wilt as the balance of salts in the compost is wrong and will literally suck out all the fluids within the plant.

Feeding once a week is enough.
If you used chicken pellets sprinkled on top, then you could just remove them.
As long as your plant looks ok, then it is ok.

I have blinds on my G/H which I leave down all summer.
Cucumber leaves do scorch easily, but it's not going to cause much damage.
Enjoy your cucumbers

 

Years ago they always stated you can't grow tomatoes at cucumbers in the same green house, of course that's not quite true but it points out they like different growing conditions.
Toms need a dryish atmosphere and will take more sunshine, cucumbers like warm humid conditions and more shade, even filtered sunshine only rather than direct.

 

I had leaves turning brown and crispy and i think it was more cold and a lack of some nutrient. it wasnt sunburn for me, it was always the old leaves that went first too. maybe the plant was scrapping them for nutrients.

 

I often find the bottom leaves going brown and crispy I put it down to them being worn out a bit like the lower leaves on tomatoes go die off as the tomato gets taller and fruit forms and ripens.

 

Picking our 1st cucumber later , I feel a salad coming on .

 

I've had about 20 cucumbers so far, of which I've had about 2.
I'm not a big fan of eating them, but I enjoy growing them and the neighbours are appreciative.

But..... I went down the greenhouse just now and look what I found!!



A ripe tomato at last!!
So that's lunch sorted for me