Yes. Chard and collards and other thick stemmed leafy greens are water blanched for 3 min. Spinach and similar tender leafy greens for 2 min.

Dave

What is your climate like? For me chard, kale, etc can be harvested fresh in winter so I wouldn't take up freezer space for an inferior product if I could it eat fresh. What temps do you get? Do you use row covers?

Ordinarily, in upstate New York we would have had a heavy frost by now with temperatures in the 30 degrees Fahrenheit range in November & December. In January we usually get below zero for a number of days. I usually harvest kale until these below freezing temperatures arrive. So is chard as tolerant to cold as kale?

No, in general chard is not quite as cold tolerant as kale. Kale will often hold up to the hardest freeze of 25 degrees but chard tends to develop some leaf damage at 30 degrees unless somewhat protected with row covers. But humidity and wind also play a role so there are no absolutes.

Dave