How long should it take for true leaves to appear on tomato seedlings?
Question:
How long should it take for true leaves to appear on tomato seedlings? Can I rescue these seedlings? I planted tomato and pepper seeds on 3/1 using an organic seed-starting mix & following the instructions of your excellent seed starting video. I placed them on a heat mat. Within 4 days, the tomato seeds had germinated, and began to grow rapidly (Pepps took a little longer). When I saw the tom seedlings were getting leggy, I adjusted the grow light to be closer (6″ or so). I also boosted the heat in their space to be around 69 at night and up to around 75 during the day. I put a fan on them. A few started to show signs of true leaves about a week ago, but the development is at a snail’s pace. Now they look yellow to me, and I fear I’ve overwatered. I am following the same process as last year — if anything keeping them warmer. Could it be the TP tubes? (A YouTube trick.) Could it be the grow light has lost its effectiveness? I’ve used the same ones for years. The pepper seedlings seem to be faring a little better.
Answer:
You should normally see true leaves appear on tomato germinants/seedlings somewhere in the neighborhood of 10-14 day after sprouting, so you’re definitely behind schedule. The seedlings you have are leggy and beginning to yellow–I fear the medium looks too wet, so you probably have some root rot or damping off occurring. Your protocol doesn’t sound unreasonable to me, and the toilet paper tubes aren’t a terrible idea for biodegradable seedling pots (though I would probably cut those in half–it’s a long tube of soil to drain), but I would switch to a sterile, soilless medium that will drain more readily and make sure there isn’t any water standing in the trays. Ideally, your growth medium will be light, moist but not wet, and somewhat loosely packed. I would advise starting with fresh seeds–efforts to dry the soil at this point probably won’t prevent weakened plants at maturity.
While this may sound like discouraging news, you are actually still early to start tomatoes indoors, anyway, so there is plenty of time to get a new batch of tomatoes going! And hopefully your little crop of vigorous pepper plant seedlings nearby will help soften the blow!
Happy gardening.