How to care for spruce seedlings?

[TimTheNewb]

I have germinated some blue spruce and some black spruce. There are about three seedlings of each, and they range from 1.5" to 2.25" tall. Pics attached.

I have them on a heating pad. I just checked with a meat thermometer and the soil at the bottom of the little pots reads about 80 degrees F. Near the top it's closer to 70 degrees F.

I water them every day with 4-8 sprays of a water bottle.

I have them under a light that automatically turns on for 12 hours and off for 12 hours.

I have no clue what to do now.

Do I leave them on the heating pad? Or take them off? Is it warmer is better, or do these plants need some cold? If they need some cold, how do I know when to let the soil get cold?

Each little pot has three seedlings. Do I keep them together? Separate them somehow? Will they compete against each other?

This light wasn't made for plants. I want to keep growing these inside, and I don't have good window space. Should I get a better light?

Should I water differently? More? Less? Do that thing where you let the water run through while it sits in the sink? I'm not very good at knowing when the soil is moist or dry, I don't think.

When do I want to move these to bigger pots?

Thanks for any help you can offer a total newb.

 

[sorce]

Seems hot at the roots.

Welcome to Crazy!

Sorce

 

[TimTheNewb]

I turned off the hot pad. Any more help?

 

[JeffS73]

A proper grow light would be better. Use weak fertiliser, don't spray it on the leaves. If they wilt, water more, once a day is ok but I normally water until water comes out the bottom of the pot. Water needs to flush through, to reduce salt build up at the roots.

You can keep them together for at least a season, after that I would separate them, say beginning of Spring 2022. Spruce are slow to get going but you can get a fair bit of growth by seasons end.

They won't do well if you keep them inside permanently, at most I would say till the end of Summer. They need to prepare for and go through dormancy to set new buds, the best way is the natural cycles of nature. You can push this around a bit.

Heres an example of a Sitka spruce I grew last year. Took months to get going then took off. I wired down the leader to bush it out:

 

[TimTheNewb]

Looks great. Thanks for the advice, I'm going to take it.

I like to understand things from first principles. Can you help me understand the factors involved when you say "They won't do well if you keep them inside permanently"? Is it about temperature and light fluctuations that we don't have indoors? Or something about exposure to fresh air, with all its invisible contents (pollens and what-not)? Or is it a moisture thing? A combination?

Thanks for your help!

 

[JeffS73]

Well, like most temperate species, Spruce have evolved with and take advantage of seasonal changes. It comes down to light and temperature. If you can replicate that indoors, great, but if you can't, the tree will lose vigour and eventually die.

For example, I started some larch very early last year, and some very late around midsummer. By autumn, the early seedlings were looking stressed, from the look of their needles and lack of growth. I surmised that they had been expecting dormancy. Larch drop needles and put energy into buds for next year, triggered by shortening days. So I put them outside, but I think they missed a month of hardening and bud development. I will know this year what the repercussions are.

As a result, my late sown larch are now entering dormancy in the garage, in February! They get cold temps and short days there, but no frost. My hope is that they will have adequate time to prepare for the next season, albeit not a deep dormancy.

My take home has been you can tweak it, but you can't cheat it!