Wildflowers are prolific and won't require a lot of your attention. Some even say they are growing tremendously well, when just scattered on top of the soil and watered down well. No need to really use sand when spreading these in containers... the important thing would be to just compress them into the soil, making sure not to bury them. A light spread over your container's surface would suffice. We would recommend containers no less than 12 inches deep. PRO Tips for Growing Wildflowers Successfully ⟐ Save the Bees! Plant a "Bee-Friendly" Garden Today ⟐ How to Grow Beautiful and Healthy Sunflowers ⟐ 38 Edible Flowers To Plant In Your Garden ⟐ How To Attract Beneficial Ladybugs Into Your Garden ⟐ Plant THESE To Attract More BEES!