Looks like you have at least phosphorus (reddish stems / veins everywhere) + nitrogen (bottom leaves yellowing and dying) deficiencies, if not other deficiencies as well.
Measuring PH is a must, as it affects the uptake of all nutrients. You need to follow @Horticulturehobbyists advice, otherwise these plants aren't going to survive.
If you are trying to avoid buying fertilizers, you can try experimenting with getting phosphorus from sources like boiling banana peels or nitrogen from diluted piss (https://www.royalqueenseeds.com/blog-how-and-why-to-create-homemade-organic-fertilizers-n764).
Results will obviously be far less predictable though than with nutrients which have recommended dosages.
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