University of Illinois Extension
Planting Annuals - Gardening with Annuals - University of Illinois Extension

Planting Annuals

Annuals, also referred to as bedding plants are sold in a variety of ways.  Depending on the grower and the size of the plant you are looking for, you can buy annuals in cell packs or individual pots.  Cell pack annuals are sold in plastic trays with individual cells or growing pockets. The cell numbers can range from 3 to 4 to 6 per pack with the cell packs sold in units called flats.  These are smaller plants and are a good plants value when many plants are needed to plant a particular location.  A few weeks may be needed for them to grow out and fill the planting bed.  Annuals can also be bought as individual plants in 3, 4, or 6 inch pots. These annuals are much larger and more mature plants and are useful when only a few plants are needed for small garden spaces, containers or to fill in as the season progresses.  These larger size annuals require less time to produce a “finished” look in the landscape.  

If the plants will not be planted immediately after purchasing, place the flat or pots in a shaded location and be sure to water them as needed.  Just prior to planting make sure the soil in cell packs or pots is thoroughly moist.

When ready to plant, remove the plants from the cell packs or pots.  The best ways to do this is to either gently squeeze or push up the bottom of the cell pack if it is pliable or turn the container upside-down, tap the edge of it lightly against a firm surface and the plant will fall out into your hand.

Most cell pack and container grown annuals will have roots that are very well developed and dense. It is a good idea to loosen the roots slightly before planting.  Do this by either breaking the root ball apart gently or cutting down the sides of the root ball with a knife.  This helps to encourage better rooting into the soil of the garden bed.   Some bedding plant growers offer multiple plants grown in containers with without individual cells. In this case, separate the plants by cutting between them with a knife.

When transplanting plants grown in individual peat pots, remove the rim of the peat pot that sticks up above the soil surface of the pot.  If left on and if the rim sticks up above the soil in the garden, the peat pot will act as a wick drying out the soil in on the inside of the pot.   Also be sure the peat pot is thoroughly moist before planting.  Roots have an easier time penetrating a moist peat pot than a dry one.

cell packs of annuals

Plants should be planted into the garden at the same level or slightly lower than they were grown in the container.   

Spacing depends on the type of annual you are planting.  Refer to the planting guidelines on the label for proper spacing.  A general rule of thumb suggests that annuals be planted a distance apart that equals one-half of their mature height.  Closer spacing obviously will result in a bed that fills in much quicker.

Carefully firm the soil around the plant and water well to work soil around the root ball and to eliminate air pockets. A starter fertilizer could also be applied at the same time plants are watered in.  Water as needed to maintain uniform soil moisture around the roots.