In Short, YES! Cellulose insulation can be sprayed directly on block or concrete walls in the basement and we recommend it.  First you want to inspect the integrity of the walls in the basement. Are there cracks that have moisture or are there areas in your basement where moisture is coming in through your walls? If there is moisture or there are visible cracks, you will need to address those issues first.

If you have a sound dry wall, then you can absolutely spray cellulose directly on the block or concrete walls in your basement. I have personally sprayed hundreds and hundreds of basements over 30 years and only have happy clients that are glad they sprayed cellulose insulation in their basement.

Cellulose naturally resists mold with the all-borate properties it fights against mold and mildew. this is a great compliment for a basement. But if there is water in your basement, you need to fix that issue first.

Also, Cellulose has a higher R-value and its effective because it stops air from passing through making it a great benefit in the basement ant the entire home.