[suziequeue]

Our courgette leaves are looking a bit yellow. The soil they are in is probably pretty cr4p and a friend recommended that we water with a high potassium fertilizer before mulching with manure.

Can anybody recommend a high potassium fertilizer? Is that just a normal tomato feed?

Thanks

[deepinthewoods]

i stir up a good dollop of fresh chicken poo in a bucket, leave it a week and feed them that. its powerful stuff for cucurbits, they love it.

[Fleecewife]

Yes it's normal tomato feed or comfrey liquid.  But potassium is more for fruit than for leaves, so I would go with the manure mulch, plus a liquid manure feed to deal with the problem before the mulch has reached the roots, or seaweed feed, and keep the tomato feed for once fruit is setting.  Next year you could prepare the planting holes with 3 spades of well rotted manure each, seaweed meal and chopped comfrey leaves, all mixed in well to the bottom of the hole.
The yellowing of your leaves could also be a virus in which case you are best to pick off the affected leaves and hope the plant survives. Cucumber mosaic virus, which does affect courgettes, tends to cause the yellowing to be mottled in a vague mosaic pattern, as opposed to following the leaf ribs, and the fruits are hard and deformed.