Fertilizing Container Gardens Some potting mixes come with fertilizer already mixed in. Some don't. Either way, container plant roots can't spread out looking for additional food in the soil nearby, so you will need to replenish soil nutrients regularly.
Good choices are a time released fertilizer mixed in when planting or a water soluble fertilizer every 2-4 weeks.
Watering Container Gardens Lack of water can quickly kill plants in a container garden. Unlike plants grown in the ground, container plant roots can't move down deeply in search of subsurface water. Check your containers daily for water needs. Check twice daily in the heat of summer and with smaller containers.
taken from https://www.thespruce.com/tips-for-great-container-gardens-1402378
Till next time, this is Becky Litterer from Becky's Greenhouse, Dougherty Iowa