Cosmos - yellowing lower leaves

This is my first year growing Cosmos from seed and the plants have been doing extremely well, growing tall and strong and now starting to flower.

Mostly they are in flower beds, but a few are clustered together in large pots.

The ones in the beds are mostly fine, only the occasional lower leaf is yellowing, but in one of the large pots many of the lower leaves (on otherwise healthy looking plants) are yellowing.

There's no sign of mildew, no dark (or light) spots, just yellow leaves.

I do get a lot of wind and rain in my area (particularly of late) so am wondering if there is some fungus at work here.

Any ideas please?

 

Fertiliser is washed out of the soil of plants in pots MadHedger. Try feeding them regularly with something like tomato food, you may find that makes a difference.

 

Thanks very much, I'll try that.

 

I'd say the same as Sheal. A regular feed with a tomato feed should soon sort them out

 

How often? Once a week?

 

Hi MadHedger,

Considering it's only an annual, I would go for half recommended strength once a week

 

Thank you kindly.