I planted several different heritage tomato seeds in coir (coconut fiber) in bog rolls (toilet paper rolls), bottom watered. They germinated in 4 DAYS and were doing great. Then the cotyledons turned yellow and fell off. Some of the seedlings died, but most of them are still alive but growing very, very slowly. What did I do wrong?
They are in a south window in a cool, unused room. I had a light on them at first; only the red bulb works. At two weeks, I added seaweed to the water. Then I went nuts trying to fix whatever it is--added Epsom salts, matches, compost tea to the water. Turned light off so they only get natural sunlight. Put plastic over them to help keep them warmer and moister. Then I poured off all the water and added plain well water. That seemed to help for a couple days, but this morning they are looking yellow again. Some of them have tiny true leaves developing.
Please help! Is it the coir? The toilet paper rolls? The red light? Too cool for them? The coir package says there are no nutrients in it whatsoever, and I bought it from a supposedly reputable seed dealer, but elsewhere I also read that sometimes it is processed with seawater.
I have more seed for most of the varieties so I can reseed if I have to. Thanks,