Honestly I would be very surprised if most people start lettuce and other leafy greens indoors rather than direct seeding them. And I would strongly discourage them from doing it.

I know many new gardeners will try it indoors the first few years but IME most seem to quickly move on to direct seeding them. In fact most - not all - of them don't require or even tolerate heat to germinate.

But if I understand the stagnation and poor growth problems you are having with your direct seeding of them it sounds more like soil nutrient issues. Do you know for a fact that your early spring soil is sufficiently high in nitrogen for them to thrive? Many aren't since N vaporizes so easily.

These are containers, correct? So soil pests probably aren't an issue. Is it possible the containers are too deep for leafy greens and their shallow roots can't cope with all the extra moisture in so much soil? Another possibility is over-crowding perhaps?

Dave

On the soil....I never really fiddle much with my soil as a whole... I have historically only had flowers and shrubs, and tend to stick with perennials and that simply 'work' in my existing organic potting soil, and to which I simply add some fish fertilizer. Beyond that I don't tend to alter the pH of my soil. I try to keep things as simple as possible, and if a certain plant doesn't work in my sun/zone/soil, then I try something else. ;-)

But as mentioned, I'm sorta new to the veggie thing. I didn't realize greens might need extra nitrogen. I can say that my kale always does swimmingly well, once the seedlings get to a certain size. Ditto for mizuna/mustard greens. But even using this same potting soil and fish fertilizer, I've never had luck with my bibb lettuce seeds, the chard or the arugula.

It also never occurred to me that a pot might be 'too deep' for my greens. Most of my pots around anywhere from 6-10" deep. But I guess it would make sense that if some greens in particular don't like their roots too wet, that a larger pot (and after being watered) is going to retain more water...maybe more than certain greens would like...

Yeah there is a concept called "perched water table" - it is the depth at which the soil moisture collects or ponds (oversimplified). But the deeper the container the lower the pond in that container so shallow rooted plants can't reach it. As a result they can go back and forth between too wet and then too dry and that can cause problems.

But nitrogen is crucial to leafy greens for good growth and since it can vaporize so easily and also drains out of the container whenever you water, it needs to be supplemented regularly. Fish emulsion is fine for doing that.

Dave

Winter sowing is something you may like Winter Sowing

Be sure to check out their FAQs and there is related forum Growing from Seed which may be helpful. Or do a google search on seed starting temps - you will find lettuce will not germinate when it gets too warm.

HTH

Thanks Dave. Water table thing makes sense as you explain it..that water will naturally fall to lowest levels of soil in container, where these particular roots can't reach. But then didn't you say something about bigger containers making the roots too wet?....so I'm a bit confused how roots would be too wet if they are unable to reach the lower/wetter parts of soil.

As for fish emulsion, while I use it with my flowers/shrubs, I've been hesitant to use it on my greens, etc. I have this notion that somehow the fish emulsion will taint any 'food' I'm growing...make it fishy? ;-)

Thanks on the winter sowing suggestion, Gumby. I have heard of winter sowing but don't really know much about it.

I have also looked a bit into hydroponics, so that's another thing I might try ...either to get a head start on plants in spring, and/or to supplement what I'm able to grow on my balcony....

I transplant all our lettuces in a high tunnel and outside. It is much faster and easier to get uniform and predictable stands. But we sow and plant 300 plus heads every 3 weeks. It takes a little more time to transplant, but I can do a 60 foot row in about 30 minutes if the lettuce plugs pop out of the tray quickly.

"I have this notion that somehow the fish emulsion will taint any 'food' I'm growing..."

I'm not sure about why you're having trouble with germination, but as for the fish emulsion... it will only 'taint it' if you spill some of it on the plants lol.

In my view... lettuces grow so fast, that as long as you have even a moderate amount of N in the soil (relative and in balance with other nutrients) you'll be fine. Same goes for practically all fast-growing greens. Something like chard, broccoli, raab, cabbage, etc... greens that are longer-lived... do need a good supply of N, but something that is harvested as fast as lettuce, spinach etc... you'll do better simply making sure that the soil is healthy before you plant, or if using fish emulsion, fertilizing while they are young and have a few weeks to get repeatedly rained upon.

If you are having trouble with germination with lettuce, even with new seed, put it in a plastic tupperware tub and put it in the freezer. Leave it in the freezer. Pull out the seed when you want to plant it, plant what you want and put it back in the freezer. We get nearly 100% germination and all we do is put the seed on top of the soil in the 72 trays we start it in and gently push it down and water from above. We sit them on a table in the basement and when they start to germinate, we move them out to the high tunnel. Germination is usually in a 1.5 -2 days.

Thanks...my problem is not so much germination, but that the chard seedlings in particular, never grow beyond seedlings...they remain essentially stagnant...often times with the seed head not even fully detaching itself from the seedling...

Also, I don't have much space...just a balcony that's maybe 50 s.f., and the rooftop where the landlord has allowed me to keep a few pots...

So are you saying that your veggies will be grown in containers all their lives? When you said 'outdoors' I think most of us would have imagined in ground planting. Container growing needs different techniques. What mix are you using?

FWIW I start always some lettuce inside because I have a massive slug and snail problem. I don't have lights, just a glass porch. But I then transplant outside into the ground. I don't need or want uniformity because I don't require a mass of lettuce at one time. Uneven growth is actually a plus if you want your lettuces in succession.

how much sun do your plants get?

Once the seeds have germinated I like to water pots from the bottom - that avoids washing the nutrients out of the bottom.

Check this seed germinating chart - note how diff lettuce is for days & temp. And how long some take when the temp isn't just right.
http://tomclothier.hort.net/page11.html

Floral UK.... all my pots, whether they be for my flowers/shrubs, and now my beginnings of lettuce greens, all contain this organic potting soil described as:

"Ocean forest is a powerhouse blend of premium earthworm castings, bat guano, and sea-going fish and crab meal. Composted forest humus, sandy loam, & sphagnum peat moss give soil light, aerated texture Ph adjusted at 6.3 to 6.8."

I also perlite to all my pots.

Beyond that, I just water and occasionally add fish fertilizer.

Yes, all my plants are in pots. I do not have a yard.

However, as mentioned, my kale has never had any issues and always does very well. Last year was my first year growing mizuna/mustard greens, and that also did very well once it got going. But none of the others (bibb lettuce, spinach, chard or arugula) did well last year, or seem off to a good start this year either..

You can very easily over water lettuce.