So this was my first year of doing a vegetable garden and I have had some hits and misses.

My main miss seems to be with starting my seeds indoors under a grow light. I watch Monty Don of Gardeners World do lettuce trays of plugs and he gets these great plants ready for transplanting but I seem to be missing something.

  • I use seedling starting soil from the local supplier.
  • I plant the seeds to the recommended depth.
  • I've been watering from the bottom up to encourage root depth development.
  • I cover them for humidity then remove once they start to germinate.

The issues I've seen are:

  • seedlings getting leggy
  • Seedlings not progressing past the initial sprout leaf stage or if they do get secondary leaves they don't develop much more.
  • Lettuce seedlings getting leggy then producing more roots further up the stem.

The leggy bit I figured was not enough light so I raised the trays and added an additional LED bar and that seems to be helping with the legginess but not the development.

Should I be fertilizing these things as well and if so what type and how often?

My tomato seedlings were a joke and my kohlrabi seedlings also sort of grew to 2-4 inches then haven't done much else since.

Is there a definitive guide to the whole process because obviously I've missed something that should be dead simple. Every video I watch has people doing what I think I'm doing then later they show these wonderful ready to transplant plugs. Heck, I remember my dad starting saved marigold seeds every year in the basement under grow lights and he never had any troubles while I can't seem to get a tomato to germinate much further than the two secondary leaves.

Garden sown seeds I appear to be a green thumbed god but as a tray starting newbie I'm a total embarrassment.

1 Answer 1


Generally warm to sprout ( 80 F+). After sprouting as cool as possible to prevent getting "leggy". Strong light is also necessary to reduce "leggy". No fertilizer is needed for seedlings.

  • 1
    I disagree on a few points: 1) In the US, seed packets usually tell you what temperatures crops germinate best at. Eighty degrees is way too hot for most vegetables (lettuce sprouts poorly or not at all at that temperature. OTOH, melons would love that much heat). 2) Fertilizer is needed after seedlings get their second set of true leaves. I'd also recommend bottom heat, with a thermostatically controlled heat mat, if germinating seeds in an unheated space like a basement or garage. Ask a bunch of gardeners for recommendations, get a bunch of answers :)
    – Jurp
    Aug 7, 2022 at 11:36
  • 1
    I did means in very general terms , not in all cases. And I assumed a potting soil would have some minimal NPK. Aug 7, 2022 at 16:35

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