Getting annuals in the ground

Annuals are simple to plant. Just follow the label directions for spacing, and dig a hole deeper and wider than the root ball. Add some compost to the hole or mix the native soil with organic matter. If desired, you can add some dry fertilizer in the planting hole and water it in, or you can fertilize the annual after .
Annuals are most frequently sold in market packs, in which six or so plants are each in separate cells. Merely turn the pack upside down and gently push each plant out of its cell from the bottom. Don’t pull them out from the top because the stem may break off from the roots. After removing the plants from the packet, plant them in the ground so that their rooting mass is slightly below the soil surface. Firm the soil around the plants and then water them in well.

Planting annuals later in the season

Of course you can plant later in the season! Plant and replant all summer long if you want and into fall if you garden in a mild climate. As long as the plants are willing and able to grow and produce flowers, why not? Because blazing hot weather is stressful, avoid planting during such spells or at least coddle the newcomers with plentiful water and some sheltering shade until they get established. A dose of all-purpose fertilizer (applied according to the instructions and rates on the container) may also hasten latecomers along.

Planting in late spring

The majority of annuals are frost-sensitive. In other words, a freeze can damage or kill them. Frigid temperatures also make annuals much more susceptible to disease damage. If these small plants are damaged by cold, they may never quite recover. Don’t risk it: Plant your new annuals in the ground only after all danger of frost is past. The same goes for plants you’re putting in containers (though you can bring the pots indoors on chilly nights if you have to).

Gardening fever hits us all on the first warm spring day. But warm air isn’t necessarily what you’re waiting for — warm soil is. If the ground is still semifrozen or soggy from thawing cycles or drenching spring rains, it’s better to wait another week or two. No, you don’t have to take the soil’s temperature before proceeding. Just remember the wise advice of garden author Roger Swain: Don’t put plants in a bed you yourself wouldn’t be willing to lie on!

Filling in the garden after the last frost

If you live in an area with a long growing season, you can go ahead and sow annual seeds straight into the ground, secure in the knowledge that they’ll sprout, grow up, and start pumping out flowers, all in plenty of time. This approach is generally easy and cheap. Gardeners with shorter summers can either start seeds inside or buy seedlings.
Freezing weather kills or at least severely damages most annuals. Therefore, the trick is to know your last spring frost date and your first fall frost date —these dates bookend the annual-gardening year. (If you don’t know, ask an employee at a local garden center, a more experienced gardener, or someone at the nearest office of the Cooperative Extension service. Note that the dates are averages; they can vary somewhat from one year to the next.)