When to fertilize the seedlings?
 

Ok the tomatoes have been up for about a week, and the Shish-ito peppers 4 days I've been told when I fertilize the seedlings for the 1st time make sure to use a liquid fertilizer and dilute it with water to no stronger than 1/4 strength. Is there a rule of thumb to use as a guide on when to fertilize for the 1st time? When I pour the fertilizer water mix into the bottom of the tray holding the seedlings, should I add so the mix is 1/4" up the side and do I leave it there for the plants, or do I drain it after the seed trays are wet? Thanks for the help.

There are lots of different theories and practices regarding fertilizing seedlings. Personally, I don't fertilize them at all until they have at least 2 sets of true leaves, usually more, sometimes much more, lol. Then I pot them up into solo cups using a potting mix that contains fertilizer and I never use a liquid fertilizer at all. They get the first dose when they go into the garden.

I'm going to mirror what Sue wrote above. I wouldn't fertilize before potting them up. There have been years that I didn't fertilize at all.

Many say that one should start the 1/4 strength fert after the first true leave open. No, I wouldn't let the plants sit in water all the time. Just get them well wet from bottom water, then remove so they can drain.

Nan

I fertilize when seedlings have their first set of true leaves. Liquid fish and kelp or just fish emulsion (depending on what I have on hand). 1\4 strength is correct for seedlings. Let them soak it up for 20 minutes or so . I use what is left over on other plants or just toss it. Good luck!

I wait for mine to get the first set of true leaves, then I use 1\4 strength M G let them bottom soak for 5 minutes.

I've been mixing a tiny bit of Schultz pelleted time-release in my seed-starting mix. The stuff is cheap, and works almost as well as Osmocote. Even with a seed touching a pellet of the fertilizer, they seem to grow fine without burning. The nutrients come out of the time-release stuff slowly enough that it won't burn plants.

Worm castings are another proven and effective fertilizer, and a component of the more expensive seed-starting mixes. They too tend to not burn plants, even though a tiny bit goes a long way.

I see I'm not the only one to divide the suggested dose of fertilizer by 4. I take a common liquid fertilizer. When do I start fertilizing ? it depends on the volume of mix tomatoes are growing in. The smallest the earlier but never before true leaves appear.

I have occasionally grown seedlings directly in 'hot' prefertilized mix. Did great tbh. I personally add some organic pellets to the bottom of the cups, for the roots to reach them when they grow a bit, but using quality time release premixed per instructions is ideal for ease of use and peace of mind.