Mine are 3 feet tall with fruit on them in 4X5 pots and have never been fertilized (and the soil is just sterile potting mix). They show no signs of any stress whatsoever. So in my opinion you can hold off as long as you want. I'll be planting some of mine this weekend! Yay!

As seedlings, they are already getting more than enough. ;) Once they are in the garden, assuming no hole preparation for planting, then you can go back to feeding them as you wish. But keep in mind that excessive feeding causes more problems than underfeeding does.

Dave

I am confused here.

One person says they have 3' tall plants in 'sterile' planting mix. Question: Does this planting mix come in a bag that says it feeds for X months?

Another says that as seedlings they are getting more than enough. A 6" plant isn't a seedling any longer and isn't getting anything from the original seed so what do you mean?

As a rule I begin fertilizing plants once the first true leaves form and I use a quickly available synthetic, not an organic source of nutrients that has to pass through the gut of a microbe before being available to the young plant. Works great in the soil, not so great inside the house in tiny little containers.

Another says that as seedlings they are getting more than enough. A 6" plant isn't a seedling any longer and isn't getting anything from the original seed so what do you mean?

Good question. ;) No, I do not agree with the comment "Mine are 3 feet tall with fruit on them in 4X5 pots and have never been fertilized (and the soil is just sterile potting mix)." That is a miracle. ;)

What I meant was since they already feeding them fish emulsion (their choice, not mine) at 1/2 strength weekly they are getting enough for now. Fish emulsion is used by many, quite successfully apparently, and it's form of N and micros is readily available to the plant according to the manufacturer.

They are already 7" tall and still have a month to go before planting out so more fish emulsion is only going to create 3' tall, gangly plants.

It's a "seedling" in the sense most use that term in that it is still in a small container and not yet in its final grow place - be that in-ground or in a large container.

As a rule I begin fertilizing plants once the first true leaves form and I use a quickly available synthetic, not an organic source of nutrients...

Your approach clearly works. I prefer transplanting them at cotyledon stage or first true leaf stage to small cells filled with a quality growing mix (usually ProMix BX) to which I add low-dose time-release fertilizer. Doesn't leach out with the frequent watering and is slow release but still readily available. And as you know from my posts on stage transplanting, they don't stay in the small cells for long. ;)

Hope this helps clarify.

Dave