CactiGuide.com

Naturally, I overwinter all of my adult cacti simply by leaving them alone, as it's too cold and dark for them to grow at all, and I've heard it gives them a nice resting/hibernation period that will help them know when to flower and start growing next spring so they can grow healthily and flower prolifically.

However, for my seedlings indoors and under grow lights, I'm not sure whether I should do the same? I have heat pads and lights, so they definitely COULD grow a bit, but it's also really cold in my basement and I have no way of climate controlling the entire room, so I'm not sure if it's warm enough. Also, I don't know if just because I COULD get them to grow means that I SHOULD. Like I said, I've heard letting them just kinda hibernate over the winter months will help them grow and flower more in the spring - but then again they're still not big enough to flower so maybe it would just be best to push them to adulthood as soon as possible.

Any thoughts or advice on this? Do any of you guys overwinter seedlings, maybe even just for a few weeks, and does it seem to help them grow faster/healthier afterwards?

Since you have artificial lights and heating you can keep the seedlings growing for the first winter. Some growers keep them in such controlled conditions for two or even three years without hibernating the seedlings, but, in general, after 1 to 1,5 years of age seedlings will be big and strong enough to overwinter same as mature plants.

Nino_G wrote: ↑Sun Jan 14, 2024 8:57 am in general, after 1 to 1,5 years of age seedlings will be big and strong enough to overwinter same as mature plants.

Indeed. Any plant the size of a pea can survive a cold and dark room without water for at least four months, that is how long mine have to stay in an unheated room during the winter. Only the seedlings of the previous year do get a little bit of water once or twice. I use a plastic bottle and poke some small holes in the cap, so water drips out when I squeeze the bottle and I pour some water over the seedlings. Hardly enough for the pots to really get soaked, just the top layer and some roots that are present there. That is it.

I am on my second season growing from seed. I have been starting them in early winter,mainly because I have more time. And when spring comes they have a huge head start and keep right on growing (That was my experience the first season anyway) Second batch will go outside in a few months,when everything goes outside
But this winter I tried both ways with the first year seedlings which are now just over a year old. ( Some under grow lights with heat mats sharing same timer) And the rest in cool room with little light and hardly any water. The fact is neither is really growing. They somehow know it's winter even though they are somewhat warm with light.
Sooo in my opinion it's kind of a waste of lighted space to put second year seedlings under lights. And my "unlit" seedlings seem to be doing just fine being somewhat dormant in rooms dipping into the upper 40's with little light.
But when started in say October they seem to grow all winter and right on through summer. But after that as was said above they act like adult plants from my limited experience.

FredBW wrote: ↑Mon Jan 15, 2024 12:10 am I am on my second season growing from seed. I have been starting them in early winter,mainly because I have more time. And when spring comes they have a huge head start and keep right on growing (That was my experience the first season anyway) Second batch will go outside in a few months,when everything goes outside
But this winter I tried both ways with the first year seedlings which are now just over a year old. ( Some under grow lights with heat mats sharing same timer) And the rest in cool room with little light and hardly any water. The fact is neither is really growing. They somehow know it's winter even though they are somewhat warm with light.
Sooo in my opinion it's kind of a waste of lighted space to put second year seedlings under lights. And my "unlit" seedlings seem to be doing just fine being somewhat dormant in rooms dipping into the upper 40's with little light.
But when started in say October they seem to grow all winter and right on through summer. But after that as was said above they act like adult plants from my limited experience.

Good advice!