I've heard that basil is more sensitive to cold than tomato. I'm wondering if it's still a little cool for them. They are not getting any sun by the sounds of it.

Cilantro doesn't like it hot, so it makes sense they are going well.

Is there a place outside where the plants can sun themselves for much of the day? They might need to be acclimatised carefully at first.

Basil usually does grow slowly at first so there's probably no need for concern. While using a fan does create sturdier plants it does seem to slow down the top growth. Usually I wait until seedlings are about a month old before using a fan.

I start fertilizing as soon as the first set of true leaves is out, and the plant is working on the second set. Starting with a very weak solution of fish/kelp, and gradually increasing the concentration every week. Otherwise they just stall, especially if you are using a sterile, no-nutrient potting mix.

Sorry guys, I never got any sort of notification that anyone had responded to me. Tete, they do get lots of sunshine. They're in a south-facing window with a grow light to supplement so they don't stretch. I live in 6A so last frost isn't until the beginning of May here - it's snowing right now actually! I actually moved the grow light a bit further away. I thought it could be too intense for them. It's LED (the 2-foot GE grow light balanced spectrum), not fluorescent, and it was only about 4 inches away.

Gj, I did slow it down with the fan. My tomatoes didn't like it and started curling. I still use it, but from much further away so the leaves barely move. I'm not sure how the basil feels about it, but when I repotted them they did have amazing roots.

JoJo, I realized this is part of my problem. I have never started seedlings before and didn't know anything about fertilizing. There's so much conflicting advice. I started them in Jiffy Mix which has no fertilizer. I was so afraid of fertilizing them too soon that my tomatoes developed awful deficiencies and my latest round of basil started to turn yellow. What npk fish emulsion do you use? I have Neptune's Harvest 2-4-1 but I'm concerned there isn't enough nitrogen and was thinking of getting some 5-1-1 and mixing them. I also got them OUT of those peat pots and into some plastic cups. Those peat pots are just awful. I spent all day watering them.

My first round of basil (the subject of this post) that I was growing to keep indoors is now doing fine and is working on the third set of leaves. Between giving my plants fertilizer and getting them out of the peat pots, the change in my basil was nearly immediate. By the next morning they had doubled in size. I wasn't sure if it was the fertilizer or the plastic cups that was helping, so I didn't fertilize my next (for outdoors) round of basil, and now they are yellowing and I'm trying to fix it. I had bumper crops of basil when I bought transplants for the garden (18 months worth of pesto in the freezer! I thought it was hilarious the absolute piles of basil I had), but starting from seed is a whole different ball game! I'm more confused now than when my son was a newborn.

Neptune's Harvest is fine -- you don't have to augment it. Even when I use a very weak solution, the seedlings seem to double in size overnight -- you're right about that! Try to resist the urge to feed them more -- just stick to the instructions for seedlings. Keep in mind yellowing could also be a sign of overwatering, so watch out for that. The great thing about fish and kelp emulsions is that they are so gentle but very effective.

When I gardened back East, I would switch to Espoma fertilizers once my plants were in the ground. Now I just use fish/kelp emulsions for everything all year round, even cactus :) No issues with nitrogen deficiency so far, and my "soil" is just sand and gravel.

That was another issue - UNDERwatering! I read that seedlings tend to get overwatered, so I waited far too long to water my tomatoes in addition to waiting too long to fertilize. They started flipping their leaves over, yellowing, and are only now recovering. I am lucky that tomatoes are so determined to grow. I haven't fertilized them anymore but will probably do it again in a week or so for my tomatoes only. My tomatoes were extemely deficient. Entirely purple underneath without a hint of green anywhere - like iridescent, neon violet colored, with yellow tops. It wasn't due to soil temps because the soil is 70 degrees. The purple is slowly starting to fade and now they're that weird warm brown color that you get when you mix green and purple together.

I wish that when people gave their fertilizer schedules, they mentioned what kind of medium they started and potted on their seedlings in. It seemed odd to me that some people staunchly advised against ever fertilizing their seedlings until transplant time or potting into 4" containers - but they never mentioned that they are using a mix that has fertilizer in it already or they use tiny little cells and pot on after the first true leaves. My gut kept saying that they needed fertilizer!

Kari, as much as I like this site, to me there's no substitute for a solid foundation of a good book. In my case it was The Vegetable Gardener's Bible by Edward Smith.

Instead of getting bits and pieces of information from multiple (and sometimes unverified) sources online, stick to one method and one schedule that's proven to work.

I've known folks who start their seeds in Miracle Grow, or another mix that already includes fertilizer, or grow their plants in compost -- there is just too much confusion with crowdsourcing.