Gardening should be soothing, relaxing and carefree, right? And it usually is. Except when you’re standing in the garden center trying to decide how many plants to buy for each of your pots, planters and outdoor containers. Are three plants enough in the deck planter, or would four be better. Five plants would make it look fuller, but is that too many?
There are several guidelines to sort the situation. First, decide between the two main planting categories that determine plant quantities:
- Instantly Full Look: These containers decorate outdoor spaces for graduations and open houses. We’d like them to look full-grown and at peak bloom immediately. Unless the event is months away with plenty of grow-time, the container needs to be potted generously with full-bloom plants spaced closely. Add plants until it looks immediately pleasing. Instantly full planters will become too crowded as the season progresses. To keep them healthy all summer, trim individual plants as needed.
- Traditional Spacing: These containers are planted so each plant has the space it needs to develop. Instead of immediately full, plants are given growth space. It takes two to three weeks for the plants to fill in the spaces, but traditional spacing gives the best summer-long flowering and is best for plant health. Traditional planting provides the longest lasting, healthiest container.
General Guidelines for plant quantities in traditional spacing:
- 10 to 12-inch diameter container – use 3 plants.
- 14 to 16-inch diameter – use 4 to 6 plants.
- 16 to 20-inch diameter – use 6 to 8 plants.
Plant quantities depend on plant type, so check labels. For example, one vigorous spreading petunia (such as Waves or Vista Bubblegum) counts as at least 3 non-spreading plants. But generally, except for vigorous, mounding spreaders, these plant quantities are good guidelines.