Lots of new and even not-so-new gardeners have trouble knowing when it’s safe to plant. Weather varies greatly from one spring to the next, so it’s not always possible to give planting time by date, but rather it may be better to go by daily high and nightly low temperatures. Watch those nighttime lows! It’s easy to get fooled by sunny days, think it‘s safe to plant annuals, and not realize until your new baby plants look limp and black that it was freezing every night because of those clear skies.
Here’s a basic, pretty reliable, best-guess list of what can be planted in what conditions.
Any time the soil is neither frozen solid nor baked solid:
Pansies and Violas (virtually indestructible plants!)
Bulbs in their seasons
March – as long as it’s not freezing every night, with days in the 50s and low 60s:
All of the above plus:
Martha Washington or Regal Geranium
Osteospermum (African Daisy)
Fairy Primrose (P. malacoides)
April – nights in the mid 30s to mid 40s, days in the 60s:
Anything listed above, if still available, plus:
Begonia, fibrous or “wax” type
Calibrachoa (“Million Bells”)
Geranium, upright and ivy
May – Nights in upper 40s to 50s days in 60s to 70s:
All of the above, plus:
Portulaca (moss rose)
Sweet Potato vine
Vinca (annual, not the groundcover vine, it can be planted anytime)
Remember there is no such thing as “average” weather. Averages are reached by going to all extremes and then pooling the results.