Cucumber problems

Fi mini cucumber plants in unheated greenhouse are growing .. but lower leaves (original ones) are going very blotchy …. Top leaves are fine …. Anything I should be doing.

(assorted pictures attached)

Have been spraying with Epsom salt solution in case its magnesium deficiency

 

Looks a bit like red spider mite to me, but seems a bit early in the season for that.

 

Does look very like RSM as Pete says.
Pots look a bit on the small size for cucs.
If you spray during the day you run the chance of scorch if the sun comes out and that could result in brown patches.

 

Not 100% sure but these may be the watering pots that are cut into a
grow-bag?

 

My cucumbers are a bit yellow too, I thought they had got scorched in the greenhouse....now I'm not so sure , sorry i cant be of any further help.

 

Those are not pots they are watering tops to Grow bags, so huge growing area.

 

Never really considered a grow bag as "Huge", more kind of just about "get by", if you feed and water like crazy.

 

"!Never really considered a grow bag as "Huge","

well its huge compared to a pot. Plus teh toppers add even more plant area. Grown cucumbers this way for several years.

 

Depends on how big the pot is that you use.

 

Used to grow mine in Grow-Bags but last year I switched to a 13L bucket
(for each plant) from b&q and didn't have any problems, was planning
on using the buckets again........but agree a bigger bucket / tub might be better.

http://www.diy.com/departments/black-plastic-1364-l-bucket/42451_BQ.prd

 

Back to original Q .... new year new plants .. same issue again.
Some people mentioned RSM ... but no suggestion as to how to deal with it.
I checked with magnifying glass no mites seen.

I know some have said don't get water on the leaves - only water on leaves is when I spray on Epsom salts mix .. can't avoid it then. ??


It seems that every year at start of growth when first big leaves arrive - it gets this issue .. once it moves on fruit arrives OK .... but keen to find out what this is.

 

I'd go with the sunscorch/water on the leaves theory. As long as the new leaves are healthy and there are plenty of them, you don't need to worry. Just keep an eye open for aphids and RSM. If you need to spray with anything, try to ensure you do it when the plants are shaded from the sun. AFAIK, there is no effective treatment for RSM, although the biological control would probably work well in a greenhouse.
http://www.defenders.co.uk/pest-solutions/spider-mite-control.html