The 3-2-1 combo mix is comprised of 3 parts ProMix HP; 2 parts mini Bark Chips; and 1 part Perlite. Lowes carries all 3:
https://www.lowes.com/pd/PRO-MIX-Gro...ontrol/3745337
https://www.lowes.com/pd/Garden-Time...n-Bark/3731889
https://www.lowes.com/pd/Sta-Green-8...ure/1000329705
Mix all 3 together in a wheelbarrow then thoroughly wet the Mix before placing in the EarthTainer. Be sure to blend 3 cups Dolomite Lime in as well as adding the fertilizer strip as per the EarthTainer written instructions below.
Raybo
