Most seedlings have enough nutrients in the seed itself for the first week or so after germination. A decent soil mix for seed starting should have adequate nutrition for another week after that. Fish fertilizer tends to be pretty high Nitrogen, which could promote fast but not sturdy growth, making your seedlings more vulnerable. A slow-release low-input fertilizer will generally produce a better seedling, in my experience. Compost tea or worm castings would be my first choice.

Arent you supposed to not fertilize seedlings? Now I'm wondering if I should have been fertilizing my plants all this time. I wasnt going to give them anything until a few weeks after transplant.

"Arent you supposed to not fertilize seedlings? "

Wow!

Bill(me) is right, and of course whatever you give them better be very fine, and the mychorrizae and bacteria in fine cold compost will help the seedlings. But if you want also something chemical, it should be something like 10-10-10.

This is strictly for seedlings, fruiting plants need a lot more K and substantially less P. Tomatoes need twice as much K and 33% of the P. I make my own 10-10-10 with a small bag of 18-24-6 I bought when the local Franks closed years ago, plus wood ash. One cup of 18-24-6 plus five cups of wood ash, spread in a trash can of sifted compost, perlite, and peat from a bale that has been around a long time, and everything mixed well.

How would you feed the seedlings with worm castings?

I agree not to feed seeds, but my sister is much better at raising seeds then I.
She mix a small amount of blood or bone mill in the seed soil.
She grew 200 tomato & 100 pepper seedlings for Spring planting one year.
They were up & running in no time.
But I would never try that myself, which is why I let her do the seeds.

Most all seedlings do not need, nor tolerate, fertilization until after they have developed their second set of true leaves.

And even then it needs to be diluted, used at 1/2 strength of less. Its use is also determined by what growing mix you are using as many have nutrients already added, the size of the container, and how long until they can be transplanted to the garden. So you have to take all those factors into consideration.

You don't mention what type of seedlings you are talking about and the needs differ from plant to plant. Some need only a small amount and some need none at all, some need only N while some benefit from some low dose P.

But as a very general rule, IF you are going to feed them, there is nothing wrong with fish emulsion as long as it is diluted and it has distinct advantages over MG when it comes to seedlings.

Dave

My potting soil for starting seeds is a mix of Fort Lite and sifted compost. This is adequate for almost any seedlings started in cell trays. I use Fort V for soil blocks. Whenever I transplant, I mix additional compost into the soil, I always try to transplant into a better medium than what the seedlings are currently in, so the roots immediately begin to multiply. With tomatoes and winter squash I add large quantities of compost, and they take off.

For using compost or worm castings as a fertilizer, I just top-dress and let watering carry nutrients down into the soil. I want a very gentle addition for small plants

On the subject of fertilizer, what do you think about Wal-Mart "saving the environment" by no longer selling any fertilizer containing phosphate? I looked at the two kinds of fertilizer they have gotten in so far and they are both 10-0-10. I guess they think all fertilizer is going to be used on lawns and will certainly run off into the water table.
Since Wal-Mart announced this policy, my local nursery has upped the price on 10-10-10 by 25%.

Have to admit that I am the lazy type. I find it easiest to simply take a good potting soil that has a certain amount of fertilizer in it and mix it with sterile seed starting mix. Last year I used either Dr. Earth or plain old Miracle Grow potting soil and mixed it with the seed starter in even amount.

I then seeded into full sized 4" pots - generally 2 - 3 seeds per pot. I'll thin after germination.

The lights are on adjustable pulleys and kept 1/2" above the top of the seedlings. I have a soft fan blowing over the plants and the room is aprox 68 degrees. I use heat mats underneath during germination.

This seems to work fine and my seedlings are better than the local nurseries. They don't get leggy at all. I may fertilize at 2 - 3 weeks with dilute fish fertilizer.

The light situation seems to be the factor that promotes legginess not the fertilizer. If the lights are too dim or far away then I get leggy seedlings.

Oh, I grow various vegetables and wave petunias this way.

Scott

"Most all seedlings do not need, nor tolerate, fertilization until after they have developed their second set of true leaves. And even then it needs to be diluted, used at 1/2 strength of less."

I agree. And this means using seed starting mix, not potting soil.

I like very dilute fish emulsion because it is bound to have all the trace minerals.

"The light situation seems to be the factor that promotes legginess not the fertilizer. If the lights are too dim or far away then I get leggy seedlings."

I agree. This is basic.

Also, after germination at warm temperature, reduce the temperature and grow them cool.

Jim

On the subject of fertilizer, what do you think about Wal-Mart "saving the environment" by no longer selling any fertilizer containing phosphate? I looked at the two kinds of fertilizer they have gotten in so far and they are both 10-0-10. I guess they think all fertilizer is going to be used on lawns and will certainly run off into the water table. Since Wal-Mart announced this policy, my local nursery has upped the price on 10-10-10 by 25%.

Not a Walmart policy, it is a 2 year old federal mandate discussed here a great deal in the past. It is geared toward reducing the over use of high Phos ferts in all applications, including its excess use in the home garden where it is seldom needed. So if you want it or are one of the few growers who actually need it, then yes you will pay more for it.

Many manufacturers, suppliers, and vendors are following the recommendations and reducing or eliminating it from their products and I for one am very happy to see it.

Most home gardeners would be very surprised to discover exactly how high the P levels are in their garden. But they don't want to spend the $10-12 to have a professional soil test done so they just keep adding it and contributing to the issues. Garden water runs into the water table just like lawn water does.

Dave

I use seed starting mix. Once I pot up the seedlings I give them an occasional very weak fish emulsion solution.

I am trying diluted tea after reading a gardenweb faq.

Here is a link that might be useful: Tea Fertilizer

I'm a little surprised to hear so much support for using dilute fish emulsion for seedlings. Sure, if the seeds are in the ground, but in sterile growing media?

My understanding is that w/o the soil microbes, the roots receive almost no nitrogen from fish emulsion, as it isn't broken down sufficiently for easy uptake w/o bacterial action. Since container germination often uses sterile media to prevent damping off, early fish emulsion use seems to subvert that too.

I'm I off base here? Because I'm becoming a bit petrified into my opinion that the sterile fertile microorganism scale is thee determining factor for choosing which fertilizers & amendments I use.

I use compost tea or nothing most of the time, soluble inorganics if there's really a problem. Also, someone correct me if I'm wrong in thinking that compost tea does a bit of an end-around on this problem, as the tea has nitrohumates that are more usable to baby roots is sterile media, but don't promote (and may even suppress) damping off.

I use the Epsoma Start liquid fertilizer, the plants love it.