What temperature is too cold for lemongrass?
Written by
Julia Anderson
Reviewed by
Prof. Charles Hartman, Ph.D.Lemongrass is sensitive to temperatures below 40°F (4°C), with frost producing immediate damage. It is a tropical plant, and its cells rupture when ice crystals form within them. I know from experience that losing plants in a sudden freeze really hurts. Protection becomes necessary more often as the forecast predicts near-freezing conditions.
Critical Thresholds
- Sustained damage occurs below 32°F (0°C) for over 4 hours
- Growth stops completely under 40°F (4°C)
- Root death begins at 25°F (-4°C) without insulation
Ground Plant Protection
- Apply 8-inch straw mulch before first frost
- Cover plants with breathable frost cloth overnight
- Install thermal blankets during extreme cold snaps
Container Solutions
- Move pots to garages or sheds during cold waves
- Group containers together against warm walls
- Wrap pots with bubble insulation for root protection
Microclimate Creation
- Plant near south-facing brick walls absorbing daytime heat
- Use water barrels as thermal mass releasing warmth at night
- Install low tunnels for extended season growing
Adopt emergency measures for unexpected temperature drops. Water the soil deeply before sunset, as soils retain heat better when constraints are applied to contain it. Cover the plants with cardboard boxes overnight, and remove the cardboard in the morning. I use old sheets and blankets for surprise frost warnings. These steps help prevent plants from reaching a state of no return due to cold damage.
Evaluate cold injury in spring cautiously. Trim damaged leaves when new growth forms. If crowns survived, plants usually rejuvenate from roots. My Florida garden recovers after mild winters; northern plants get replaced. Limitations in your region mean realistic expectations.
Reliable overwintering of container gardening is critical in the cold zone, so plan on moving pots indoors by bright windows before the first frost. Temperatures between 45°F and 55°F (7°C-13 °C) are fine and don't require watering during that time. Overwintering indoors will guarantee survival, which is difficult to achieve with in-ground plants. Return plants outdoors after the last frost date has passed.
Read the full article: How to Grow Lemongrass Successfully at Home
