I got my Brussel sprouts started early. They are in the ground (zone 5), but I think we are getting one more 30 degree frost on Friday. They are small little seedlings right now. My question is, can they stand a frost even in the seedling stage or do I need to doctor them to make sure they don’t die? Also, they are very dark green in color and are quite small despite getting good sun. Do you think there might be a pH problem? I believe my soil is a little basic so I tried watering them with diluted vinegar a week ago. Any pointers here are appreciated.
I would have thought watering them with vinegar would do them more harm than a light overnight frost. Acetic acid is used as a herbicide and as a moss and algae killer. It is unlikely to make any permanent change to soil pH.
Brassicas are "cold climate" plants (they prefer temperatures below 70F/21C and usually "bolt" if the temperature reaches 80F/27C) and mature plants are frost hardy down to at least 20F. Sprouts can be buried under three feet of snow in winter for weeks, with no ill effects. The distinctive flavour of sprouts is actually a natural antifreeze compound.