“Lettuce Keep Cool” with the CANOVI Heat Tolerant Lettuce Trials

Posted on Wednesday, 6 August 2025 under The Bauta Family Initiative on Canadian Seed Security

In partnership with The Bauta Family Initiative on Canadian Seed Security, we have been conducting and participating in the CANOVI (Canadian Organic Vegetable Improvement) trials for the last 3 years. This year, all three of our Seed Farm Hub Sites are participating. The lettuces are planted out around the summer solstice on June 21st and assessed for characteristics as they grow through the heat of the season.

At our Sandown site, some varieties suffered during planting, and a few seedlings were lost. However, the moderate weather conditions have been ideal for lettuce growth, with many plants showing significant growth and some now big enough to harvest.

In 2024, our Vancouver Island Coordinator planted some seeds she acquired at a market in Oaxaca, Mexico. The seed was labelled “Lechuga Lisa” (which we later found out simply translates to romaine). After observing the crop in the first year, we let a unique red offtype go to seed and planted seeds from that this year. That particular variety, a gorgeous red romaine, planted at the same time as the CANOVI varieties, is now thriving and exceeding the growth of most of the other lettuces planted. In our seed work, we often look for regionally adapted varieties, but alongside that, there is much value in acclimatizing seeds from other areas to a new growing situation. The networks we develop with nationwide and sometimes even global seed saving initiatives will provide us with resilience and adaptability that strengthen our food systems.

Lechuga Lisa. This lettuce was planted May 16 and transplanted June 19. This 1.75lb head was harvested on July 24.

As part of the 2024 Citizen Seed Trial, we tested how readily two lettuces would cross with one another when planted in close proximity. The result was less than 3% of the time in the varieties we tested with over 100 gardeners across BC. At our hub site in Aldergrove, we collected seed from one of these chance crosses and are growing them out this season. There is a red and a green variant, and they appear to be very heat-tolerant, growing in a greenhouse and showing few signs of bolting to seed at the beginning of August. If they make seed by the end of the year, these may be another great contender for heat-tolerant lettuces for our region.

See pictures of the CST 2024 cross here:

Humans are not the only ones enjoying the lettuces.

This work was made possible by funding from the Victoria Foundation, The Bauta Family Initiative on Canadian Seed Security, and the Greater Victoria Savings Credit Union (GVSCU).

For more information on the Canadian Organic Vegetable Improvement trials, please visit SeedChange’s YouTube channel, where you will find past webinars and helpful tutorials.