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I’ve got variegated seedlings 10 months old. They have quite a few spines, but the bumps they grow maybe have one or two per seedling and aren’t much bigger than months ago. They seem undersized for this age. I have them under a gro light 8 hours a day uncovered and the soil is kept moist but not soaking wet.

Have you been fertilizing them?

jerrytheplater wrote: ↑Wed Mar 15, 2023 9:00 pm Have you been fertilizing them?

Yes I have twice.

I've just learned this myself, but you should be fertilizing your seedlings just as often as the full grown plants.

I did it by "mistake" in two pots containing my Frailea parviflora that had seeds sprout along with the adults. I didn't do anything special for the seeds. I have to dump the pots in a few weeks and plant all of the seedlings. They have really grown well compared to another pot of Frailea castanea with seedlings only. Not as much fertilizer in the second pot.

Secondly, it was also the advice of a really accomplished grower of cacti and succulents on this forum. He sows seed a lot. He told me I should be fertilizing my Euphorbia tulearensis from the moment true leaves start to show. I'm doing it every other time I water. I have been and they are doing well. They are at two leaf stage now.

A photo with some type of scale included so we can see the size would really help.

I can’t upload photos too big, very annoying!
I’ll try fertilizing more.

8 hours of light is too short a day in my opinion. Aim for 12 at least. Remember, most cacti are summer growing (or spring and fall growing) and at the solstice, days exceed 14 hours of light. Try to simulate those conditions. Together with that is warmth. Your seedlings will slow their growth if they are kept too cool. 80F (27C) during the day is probably good enough. Night temperatures can be much cooler.

MrXeric wrote: ↑Thu Mar 16, 2023 12:10 am 8 hours of light is too short a day in my opinion. Aim for 12 at least. Remember, most cacti are summer growing (or spring and fall growing) and at the solstice, days exceed 14 hours of light. Try to simulate those conditions. Together with that is warmth. Your seedlings will slow their growth if they are kept too cool. 80F (27C) during the day is probably good enough. Night temperatures can be much cooler.

I can give longer light. My temps are in the upper 60’s so you might have solved why they barely are growing. As it gets warmer out the room they are in gets hotter as summer gets closer.

keithp2012 wrote: ↑Wed Mar 15, 2023 10:57 pm I can’t upload photos too big, very annoying!
I’ll try fertilizing more.

I use https://picresize.com/ to make my photos smaller. Others use Imgur as a photo hosting site.