Preventing Overheating Under Garden Cloches On Bright Sunny Spring Days

Cloches provide delicate plants with protection from frosts, cold winds, and animal damage while warming soil in spring for easier planting.

Glass barn cloches and cold frames are semipermanent structures requiring careful installation; plastic domes and jars offer less-expensive alternatives suitable for individual plants; even these covers must be vented to avoid overheating.

Temperature

As with clothes, garden covers come in various thicknesses to meet individual requirements. Thin coverings allow sunlight to reach plants but provide only minimal protection, up to 28 degrees. Covers with greater insulation may need venting on hot days; layering straw, compost, shredded leaves or pine needles over these greater insulation covers can provide temperature regulation while simultaneously supporting perennial roots and shrubs with strong spring returns.

Water

Frost cloths, garden blankets and old sheets can quickly create an effective barrier that keeps tender plants safe from frost. Use breathable fabric such as wool or cotton rather than plastic which traps moisture and damages plants. When using plastic, ensure it does not touch directly on plants directly and promptly remove when temperatures increase to prevent overheating.

Mulch serves as a natural insulator and maintains uniform soil temperatures, offering added protection. Applying 2-3 inches of mulch around the base of each plant – keeping an inch away from stems – may help avoid temperature fluctuations and protect sensitive transplants.