It's not uncommon to have the chlorosis your plants are exhibiting accompanying the use of soils that have large fractions of coir or CHCs. I mentioned (I think here) recently that there are pH issues associated with the use of CHCs that make many of the minor elements difficult for plants to assimilate, and excess water retention can make it difficult for root function/metabolism to work at the level of the plants genetic potential within the limiting constraints of other cultural factors. When making your own soil with CHCs, it's virtually impossible to use lime a a source of Ca/Mg because of CHC's already high pH. Odds are very good you're seeing some of the results of that high pH level in the chlorosis, as noted. If you don't/can't use lime you may well need to go to using gypsum + Epsom salts as your sources because almost all soluble fertilizers that utilize urea for their N lack Ca and Mg. These compounds are very good choices because their impact on pH is not significant enough to be a consideration. The things I would suggest, in the order I would select: * Start the repotting process into a durable, fast draining soil with a more favorable pH asap. * Acidify your irrigation water to help compensate for the high media pH. Add enough vinegar or citric acid (find where they sell supplies to make wine) to bring your irrigation water to a pH * If it was someone else, I would caution them to water correctly, so they are flushing the soil at every watering, but I'm sure you're wellversed in how to water correctly, so I'll spare the details. If I think of anything else, I'll let you know. Good luck, but I'm sure you'll have everything straightened out in no time. Be sure to remember this thread so you can post pictures and let us know what you did. Al

I uploaded a photo, but it's not showing. Any ideas what went wrong? I'll try again in this reply.

Agreed. Also, I know that heater looks reasonably new, but when it comes time to replace the water heater, consider a hybrid electric instead. They are cheaper to run than a gas tankless, and it would eliminate the flue altogether. Consider the cost of relocating that flue vs replacing the heater with a hybrid electric.

I wouldn’t be surprised by lemon cucumber, but I agree with GG48 that seeing the insides is needed