what's sprouting in my cold frame

Kathleen Sayce ksayce@willapabay.org
Sun, 26 Feb 2012 13:48:59 PST
Kathleen wrote

> Veltheimia bracteata gets water spray from the open section, so 
> those plants are growing strongly.

Jane wrote:
Kathleen, how cold do you think it gets in that frame? I have a huge 
pot of this Veltheimia that I grew for many years in the solarium of 
my previous house (still for sale, solarium and all), but my new 
house has nowhere much to keep plants completely frost-free in 
winter. Kept in the living room it doesn't flower. I've been 
wondering whether I should try some of the bulbs in the center of the 
bulb house, or just send them all to the BX.

Kathleen's reply:
The one still-working wireless thermometer I have says it stays between 45 and 60 F most of the time. It has three sections; in winter I crack one open 4 inches unless temps drop below 37F outside, in which case I close all the sections. Given that the temperature cannot be even everywhere inside, I suspect some areas drop to 36-38 F if I am slow to close it up as freezing weather approaches. It does not frost, in so far as I can remember to keep it shut on cold nights. I noticed snow in the hills today down to 1700 ft, and it's been hailing, snowing and raining in showers today, but the cold frame was at 48 F overnight and is now in the high 50s. 

Once temps are above 45 F at night consistently, I open all the sections to 4 inches with blocks, and for the summer, put each lid up on 8 inch high spacers so that air can circulate easily. Calochortus love this; they are much happier in the cold frame than outside. So does Scilla peruviana and other bulbs can tolerate cold but like drier conditions than my climate provides. 
Photos are at:
http://flickr.com/photos/n7ong-photos/… for those who might be interested. 

Which brings me to a suggestion: many of us have cold frames and other climate modifying structures. Might PBS have a section where these structures could be shown, a Growing Methods and Structures section? Greenhouses, Jane's lovely new house-sized cold frame, covered porches (a la Ina), traditional small cold frames, wire racks, etc?

Cold frames are a slippery slope to cold greenhouses, and house-sized cold frames, I know. Mine is 4 x 12 ft and it's jammed full now with pots of seedlings and tender species, only some of which are leaving for new homes this spring. Only took two winters to fill. 



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