Q.Nutrient Deficiency Of My New Grapevine?
Hi, I’m new to these forums and I just bought a grapevine on the local nursery shop. The plant had a yellow taint on most of her leaves so I felt compelled to buy it and cure it. Do you think like me that it’s a nitrogen deficiency? (See image below) I would like to hear your thoughts on the problem and the remedy, as I planned to just hit it with regular care, some pruning and all round slow releasing fertilizer. Cheers! Pablo

Certified GKH Gardening Expert
I see something more sinister than a nitrogen deficiency. This looks more like the symptoms of downy mildew. This can be a problem, and will kill the vine without treatment.
General, broad spectrum fungicides will help, here. I would, also, put it into new soil. If it were me- I would line a large pot (with drainage holes) with gravel or growstone, mix some compost into some potting soil and use this as your soil.
These two remedies, together, will get rid of the illness and set it up for the next stage in life.
Here are some articles that will help:
https://www.gardeningknowhow.com/garden-how-to/info/using-fungicides-in-garden.htm
https://www.gardeningknowhow.com/edible/fruits/grapes/container-grown-grapes.htm

Thanks for the answer @BushDoctor
We still have 2 months free of rain and full of sunny hot days here and from what i've read, this fungal disease doesnt like dry and hot conditions.
Instead of doing anything I will try to monitor the plant because it has been a week and the spots are not progressing at all, not even affecting new growth. Our climate might aswell kill it for good. (Canary Islands)
I bought the plant from inside a nursery and it was very humid and with partial sun, so it might have caught the infection right there.
If the situation becomes worse I will follow your steps, thanks!