It does look like chlorosis. The cause? Too acidic growing medium?

It's not normal - how are you supplying nutrients?

Al

I was feeding with a 1/4 strength diluted MG.
After the first reply from James I added pellitized lime to the top of the gritty mix.
I hope that will make a difference.

Dave

It will probably make a difference, but most likely not the one you were hoping for.

First - there's no question the leaves are chlorotic - that's a given. Second - I think the guess James made is off the mark for a couple of reasons. First, when chlorosis is pH related, and it very often is, it's almost always related to HIGH pH, not low pH (acidic). The reason for this is that most micro-nutrients become MORE available as pH decreases. High pH causes several (mostly micro-nutrients) nutrients to precipitate and become insoluble, which makes them unavailable to plants, so adding lime would be exactly what you don't need - especially if you followed the recipe for the gritty mix. If you're using the gritty mix and your fertilizer doesn't supply Ca or Mg Yyours doesn't), you should use gypsum (not lime) as the Ca source, and Epsom salts as the Mg source - neither notably impact pH which is why they're a better choice than lime (for the gritty mix).

You didn't say how often you were fertilizing, and your watering habits enters into the equation as well, so it's difficult to say at this point whether your issue is a general lack of fertility, or if it's perhaps my prime suspect - a Mg deficiency (none to be found in how you're proceding and the interveinal chlorosis supports Mg as well.)

Al

Thanks Al and James for your good advise. I will add those items and hope to see a change in the leaf color.

I think that if you don't slow down, take a deep breath, and try to get a handle on what is and isn't likely to produce benefits instead of limitations, you'll soon be disappointed. You said you will "add those items", but no one I noted, including me, suggested you add anything. Adding nutrients/soil amendments on either your own or someone else's whim almost never ends up the way you hoped. Tweaking and fine tuning are best left to those who understand soil science and physiology - the big picture. You would be much better off if you concentrate your efforts on learning how to get the basics right. I promise you'll be amazed at how healthy your plants will be once you get the basics - a good soil and proper watering habits, the right light and temperature, a good fertilizer, are about all you need to keep yourself out of trouble ...... and of course, if you live in zone 6, your plants should be dormant/quiescent & snoozing away the winter in a nice cold garage or another spot where you can keep root temperatures between 28-42*.

Al