I don't believe it.

I could not believe my eyes this morning. I made a light box 5 days ago (see earlier post) and filled it with trays of seedlings. I also put some Coleus in that I had bought as plugs 9 days ago, and repotted. I removed the tray this morning to rearrange the items, and saw the following.



The two Coleus on the right had been left out of the box because there was not enough room. The other Coleus had been in the lightbox for just 5 days. The empty tray (lower right) was what the Coleus were in 9 days ago when I bought them. You can see how they would not fit in now. It is interesting to note, but totally logical, that the more green in the leaves the larger the plant - chlorophyll at work.

It has confirmed that the light level in the box is roughly right. In addition because the box is enclosed the tubes have raised the temperature inside some 7C above ambient.

 

That's pretty convincing, Peter! So now what with the coleus? Will you be gradually hardening them off now? I would probably have put them directly into my greenhouse, and they would be growing quite slowly. It would be interesting to compare how the plants fare afterwards, which ones perform and last best........ how about using those two as controls throughout? Or will you pop them into the light box now?

 

Debdro - I hadn't given them a thought. I just saw them looking cheap! - �£2.99 for 12. I have always fancied a try.

I know they like it warm - is your greenhouse warm enough now - or is it heated. I have just had a google and it says minimum of 15C, but will just tolerate 10C if dry. This does create a bit of a problem of what to do next. And yes I should keep those two as a control - I will go and take them out of the lightbox where I put them a couple of hours ago.

 

My greenhouse is on frost-guard this year, but last year, when I grew a load from seed, I did have the heating on a bit higher than that, so I can't be too sure about that. They certainly grew well under last year's conditions. I started them offin one of those large polystyrene cell trays that you get from commercial growers, where you get hundreds of tiny cells. I had a lot of success using that, putting it into a VERY large clear plastic bag.

Definitely interesting,isn't it? :D

I found this bit of info on a site about coleus, which rather agrees with what you said...

"Coleus plants will adapt to a wide range of temperatures above 55 degrees, but will grow best when they are kept between 70 and 85 degrees. "

It's on a nice site called The Garden Helper

 

Pete, Dendy, I think 70and 80 degrees they recommend is just too high for coleus as it will induce them to flower (and we don't want that) and cause leggy growth. I have just germinated 100 Wizard and 200 Black Dragon at 22c and had 80/90% success rate, and will grow on at 14/20c.
The Black Dragon will be planted out in a bed 1st week of june so may have cool nights to contend with but they usually get going by july.
This is just my own experienceof them.

 

Thanks Strongy - thats interesting. Will they survive in a greenhouse, or in my case a summerhouse, where it could go down to zero but not below - I have a thermostat set at zero. The information I saw said not below 10C.

 

I dont know how to go to previous post so what is a light box?

 

Hi Jean. I posted this only a two or three days ago but here have been so many threads that it has got buried. I should have given a link http://www.gardenerscorner.co.uk/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=1;t=002728

Basically it is a box for growing plants under artificial light - and also heat because the lights heat up the box as well. As highlighted recently by the lady growing cannabis, who has appeared once or twice on the news. Its also useful for seedlings and other plants as well over the winter when light levels are low. It makes the plant think it is mid summer.