Monitoring Soil Temperature: Key to Weed Control and Caladium Planting

Just as body temperature determines vacation outcomes, soil temperature dictates garden success. Flowers won't bloom, seeds won't germinate, and peach trees won't fruit without proper warmth. Two landscape tasks are directly affected by soil temperature—knowing yours can mean success or failure.

Too Late for Lawn Pre-Emergent?

Summer weeds like crabgrass need several consecutive days above 55°F to germinate. Surface seeds warm quickly; buried seeds take weeks. To know if it's too late for weed preventer, check soil temperature. Use an indoor/outdoor thermometer with bulb 1 inch deep, or the Georgia Environmental Monitoring Network for accuracy.

In Duluth recently, 2-inch soil temperatures hovered in the low 50s. Some crabgrass has germinated, but many haven't. Applying pre-emergent now and watering it in still provides good control. Monitor your area's soil temperatures to decide.

Planting Caladiums

Caladiums are tropical bulbs needing soil above 65°F, preferably 70°F+. Cool soil damages them—they may refuse to sprout. Though in garden centers for weeks, wait until early May to plant. Buy now but store in a warm, dry closet. Or start bulbs in black plastic pots for a head start, then transplant when leaves reach 6 inches.

More Information:

• Flowering Bulbs for Georgia Gardens
• Caladiums as Landscape Plants