This is a direct response from Jerin to me when I asked a similar question about winter frost
Thanks for reaching out with your question about winter frost. Yes you use it stand alone or with ruby but no bases the second to last week for 5-7 days before starting your flush week. Don’t over water obviously but if you water every day 5 is good enough. And if your more like every other day you would want to go the full week to get at least 3 waterings with winter before starting flush. Hope this helps. Let me know if you have any other questions.
Also if you don’t do a plain water “flush” week the final week of flower let me know and I can give you alternate instructions. This isn’t how we originally had people use it but there are a lot of people who step down nutes the last couple weeks but don’t go to plain water before harvest. Long story short you would use winter alongside your nutes the last 2 weeks of flower as opposed to standalone the second to last week followed by a week or so of plain water.