Growing romaine lettuce through the winter!

I think I’ve alluded to the growing of lettuce in cold frames in some earlier blogs. Not sure, but that's part of getting old I guess. My mind goes, comes back and then goes again. But, if you're wondering whether it can be done. The answer is yes! Just make sure to check out my seed starting video.

So OK, any earlier blogs not withstanding, I decided to start twenty romaine plants from seed about three weeks prior. (I choose romaine because they can withstand cold temperatures and are generally healthier than leaf lettuce). These have now grown to transplant size (about 2 to 3 inches tall) and have been transplanted into both of my small cold frames (10 in each) that were originally built in 2008. (I produced a You Tube video on these in case you might be interested). Over the last few days, I have refurbished the frames by adding some fresh paint and resealing the glass panes in the window frames that cover the top of each. As you can see, the end result looks pretty good.

During the past two fall and winter seasons, I learned that if I started my plants early enough, I could grow them to close to maturity and then hold them in a kind of suspended animation until I got a chance to harvest them later in the year. The key to doing this was to monitor the inside air temperatures (I used a wireless thermometer to monitor changes from inside my home) and to add heat via a forty watt bulb when needed. I’ve found that by keeping the air temperature in the frames in the forty to fifty degree range, I could keep the plants healthy for a long period of time. I also had to make sure not to let the leaves touch the window panes above the plants on cold days as that would turn their tips brown. That’s one of the reasons I decided to add a little height in one of the frames (designated as CF1). It was only four inches or so, but I think that will help. We’ll see this winter how that works out.

Head-space Increase

By adding a quickly made frame made from 2x4’s onto the top of CF1, I was able to increase the head space appreciably. In CF2 and CF1 the growing surfaces are the same at about 32 inches wide by 21 inches deep (roughly 4.7 square feet each). Head space, however in CF2 is eight inches in the back which tapers to 3 inches in the front compared to CF1 which now has 11 inches in the back versus 6 in the front. The increased area should allow for larger plants. That is one thing I hope to quantify as we go through the fall. By mid November all growth will have basically stopped and I’ll do a follow up blog at that time.

Soil Condition

At the last minute, I decided not to add any amendments to the soil in either frame. A casual inspection revealed to me that the soil is dark with a high crumb structure. It also appeared to be high in humus content, so I will wait to see how well the romaine starts grow before making any changes. If needed, I have blood meal available to increase the nitrogen content. (I may elect to do a full soil test by the end of the month, but for now I want to go with my gut instincts).

So that’s the deal. I’ve cleaned up my cold frames and transplanted the young lettuce starts. All that’s left to do is hope these plants get big before the cold stops them.