Stagnant seedlings HELP

[PrickPrickBloom]

I really questioned my methods yesterday when someone on the forum I sent seeds to over the winter messaged me with pics and their seedlings are probably 2x bigger in size then mine from last September. So my question is do seedlings stay stagnant and eventually die off even though they don’t appear t be growing? I went all in on my first sowing with 70+ varieties all but just a few seem to be growing a lot in size. I left most in baggies 3-5 mo’s took out. They are under led lights but probably only 3-5 hours a day as someone is fire paranoid (not myself) On a table also right next to a North facing window, room temp is usually around 70 F. I started with daily waterings and now am back to about every 2-3 days. Just curious if they are green and like mini mes there still ok? Just curious as to how some are getting monsters in so little time and mine seem beyond slow motion other then a couple species...

[Aloinopsis]

Some species grow extremely slowly. I have Blossfeldia which are a year old and under the size of a pencil lead. I have some Mammillaria who are 3 months old and the size of olives.

[crispy224]

I will say when I first started growing cacti seedlings about 2-3 years ago. My seedlings grew very slow. I hardly ever watered them and never fertilized them. I now use very diluted liquid fertilizer every other watering like 1/5 the strength and my seedlings grow quite a bit faster. obviously cacti seedlings can survive drought and poor nutrients they just won't thrive.

[greenknight]

They need more than 3-5 hours a day of light - 8-16 hours will make them grow faster.

[7george]

On a table also right next to a North facing window, room temp is usually around 70 F.

This is cold, almost winter for cacti. Give them 30+ C maximums daily, also longer days (direct sunshine or grow lights)!

[toadstar]

I'll respond to your pm here: I have a set of T5 fluorescent lights that I use for my cacti seedlings. The lights do get a little warm so I've never used a heat mat but I'm not sure of the exact temperature either (I'll try to measure that soon). They're on a timer for 12 hours a day.

I use the typical baggy method for germination. Most of the seeds that I've tried so far are of common/cheap/easy species that tend to sprout within a week or two. And because I'm not fastidious about sterilizing my soil, I open up the bags to let it dry out slightly to help combat any algae and mold growth after a month or sooner if needed.

For the next few months then on, they get watered 1-2 times a week with a half strength houseplant dose of Miracle Grow every other week. By the time winter rolls around I cut back watering and only do so when they're starting to look a little shriveled.

The first time I started from seed I was in the same boat and my seedlings hardly grew at all for the first couple of years. They still grow slow but a little bit fertilizer helps some.

The Trichocereus grandiflora seedlings that prompted the question at two months old.
Some other Stenocactus and Rebutia seedlings at about one year old.

[PrickPrickBloom]

Ya I kind of figured they were lacking lighting. I just got my LED lights maybe 2 months back and some have seemed to perk up a bit since running them, but some not at all figured some are just very slow growing. If I had it my way they’d be on a timer for 12-14 hours a day, not just when we are at home. I do have some liquid fertilizer I add into the water. Thanks for the advice guys!

[Vingames1]

Ya you need to have them on a regular light schedule and more than 5 hours a day or they’ll never grow