diff --git a/app/models/form/admin_settings.rb b/app/models/form/admin_settings.rb
index 3a7150916..1e6061277 100644
--- a/app/models/form/admin_settings.rb
+++ b/app/models/form/admin_settings.rb
@@ -67,7 +67,7 @@ class Form::AdminSettings
   validates :bootstrap_timeline_accounts, existing_username: { multiple: true }
   validates :show_domain_blocks, inclusion: { in: %w(disabled users all) }
   validates :show_domain_blocks_rationale, inclusion: { in: %w(disabled users all) }
-  validates :media_cache_retention_period, :content_cache_retention_period, :backups_retention_period, numericality: { only_integer: true }
+  validates :media_cache_retention_period, :content_cache_retention_period, :backups_retention_period, numericality: { only_integer: true }, allow_blank: true
 
   def initialize(_attributes = {})
     super