As the title implies we have a challenging discussion ahead of us today, growing a crop like garlic in extreme cold! The standard in our part of the world is fall sowing hardneck garlic and spring sowing softneck. Just a quick point of clarification Hardneck varietys are the slower maturing more cold hardy garlic that produce a scape, possibly even a head that will produce small bulbs. Softneck garlic on the other hand is quick to mature, produces no scape, yields more bulbs and needs warmer temperate weather.
We start both hardneck and softneck garlic by doing a late winter or early spring sow, almost always around a decent sized heat sink due to our climate. The only way to sow this time of year in our area is with the afromentioned heat sinks. They keep that specific microclimate much more stable as well as keep the soil lose. We tend to use either large rocks or the foundation of structures for our heat sinks, things like below ground water tanks or sidewalks etc. would also be a great choice.
With Softneck this yields mixed results, if we sow to early and get a late year evening of -40 it will certianly spoil the crop. When your growing season is around 100 days or less this is a reality you have to accept. When we have a favourable early season (warm) the softneck thrives, yielding abundant delicious small cloves great for curing or going straight into the kitchen!
Saving the best for last, Hardneck being so cold hardy is obviously our favourite cultivar to play around with. We've actually never had a harvest fail with hardneck using the heatsink method. The coldest temps our bulbs have survived is roughly -45, even after weathering such extreme temperatures they produce 4-8 full sized bulbs at the base and hundreds of mini bulbs for next season on the scape. In that trial we used blue and red russian garlic, specfic cultivars grown in our part of canada for over 100 years and easily sourced at your local grocer's.
Thanks for taking a minute to explore growing garlic in extreme cold temperatures with me this morning and feel free to reach out with any follow up questions you have.