Is organic fertilizer even effective on soilless media? or is it just compost that is wasted on it… maybe your wuestion will elicit clarification about that. i would also like to know if there’s a difference betwee liquid fertilizer purchased as such and powdered fertlizer that you apply as a solution after mixing with water.…

I’ve wondered the same thing i heat sterilize my seed starting mix so there are not beneficial organisms alive in it, which I believe are needed for organic nutrients to work. i am not a soil scientist so I may need correcting there. i would like to market my seedlings this spring as organically grown so am hesitant to grow them using chemical fertilizers

I grow all my seedlings in container soil and never fertilize them. It always makes me wonder why people like to complicate things so much?

There is nothing complicated about supplying basic nutrients plants require to thrive and be productive. If no nutrients in the soil mix/media, then they will need to be applied manually. ALL container plants require this.

High quality potting soil has enough nutrients for seedlings from germination until the time when they can be moved to their permanent location.

Unless it has been incorporated during processing, "high quality potting soil" has virtually NO nutrients!

Nevertheless my seedlings grow very well in such a soil without fertilizing 🙂

Perhaps people are thinking of different media. Certainly seed sowing media sold here do contain fertilisers.

I grew the past seasons tomato seedlings in nothing but peat in my south facing window. I usually add some mushroom compost or well composted horse manure. What I do is put a layer of peat in the bottom of a 12 oz foam coffee cup. Then a layer of peat mixed with the above. On top is a layer of only peat.. The bottom layer serves as a filter. The top layer as a buffer.

While this years seedlings weren't quite as full as usual they grew into useful plants. I'm guessing that the more light your plants get; the more fertilizers they need.

I remember when there were many sources of seedlings each spring. While they were grown in green houses they were no where as large as those sold today. But since the growers were scattered all over, there wasn't the same problem with diseases and fungus problems as there is today. There wasn't much difference in the size of those plants to what I grew this year in my window.

floral, it would be highly unusual to find a prepared seed starting soil with fertilizer additives in the US. These are typically very loose, lightweight ingredients and sterilized to minimize the plethora of fungal issues that can affect germination and seedling development. And seeds supply all their own nutrient requirements until well into the seedling stage and time to pot up anyway, so no fertilization of any kind is required at this early stage and is just wasted or an unnecessary expense.

And if you did find one, I'm pretty darn sure it would not be an organic addition!!

Plenty of organic seed starting mixes are available here containing nutrients sufficient for several weeks. I wonder why the difference?

Don't the cotyledons (seed leaves) provide nourishment for a while?

I use Maxicrop seaweed extract and compost tea to water seedlings once the true leaves emerge.

Maybe it's the difference between "seed starting mix" and "potting mix". I use Proplan HP for seed starting. It has no nutrients. When I pot them up, I use Proplan for Herbs and Veggies which has added ferts which are organic.

Did you mean promix Labradors? ive been looking at it but i use quite a bit while growing my tomatoes for family and friends. have hesitated due to cost . i think Walmart has it here. will check it out Thanks for your help!

I DID mean Promix Ken. Proplan is a dog kibble that I haven't used in years {LOL}. Sorry about that! I have corrected my post.

I've been growing tomatoes from seed for more than 20 years. I use a professional seed starting mix, but never bother with any fertilizer for my seedlings.

I would very lightly soak seed starting mix with MG. like one third strength.

Later when the seedlings grow true leaves I fertilize the with the same.

After potting I up the strength a bit.

I have never used organic ferts on seedlings and starter