Organic fertilizer for seedlings

(Question)

Hi there

2 weeks ago i sowed seeds for tomatoes and cilantro and now they have germinated and see true leaves for both.

I sowed them in starting mix so no other organic material for seeds to feed on. I wanted to ask if i should add any fertilizer while watering them?

I prefer organic fertilizer and what i could find in other online resource was some kelp mixes, fish emulsion and organic choice from miracle gro.

I couldnt find any in canadian websites so i was looking for help to see what my options are.
This is resource i was following
https://www.youtube.com/watch?v=DUsD_fduWew

thanks

(Answer)

Thank you for contacting the Toronto Master Gardeners

Sowing your plants indoors and raising them into seedlings while it’s still chilly outside is a way to get a jump in the growing season.

When seedlings first emerge from the soil they are still feeding off of the food that is stored in the seed. The first two leaves produced ( in the case of dicots) are called cotyledons. Cotyledons contain the remainder of the stored food reserves of the seed, and they keep the seedling fed until the first true leaves sprout and the plant can begin photosynthesis.

Once you see the appearance of the first two or three sets of true leaves emerge, the seedlings will require a lot more of light, make sure to move them to a bright room to prevent the formation of long skinny etiolated stems.

Once your seedlings develop 3-5 leaves, this is the time to thin out your seedlings if you haven’t done so already. At this point, you should begin fertilizing your seedlings. Some brands of soiless mix contain small amounts of fertilizer so before you reach for the fertilizer make sure that you are not using a soiless mix that already contains fertilizer.

You can use a general purpose fish emulsion fertilizer diluted to 1/3 it’s normal strength once a week.

Garden Making has an excellent PDF entitled Starting Seeds Indoors.

You may also be interested in the Toronto Master Gardeners Gardening Guide: Growing from Seed