How to keep plants alive in winter outside?
Apply mulch and water soil before a freeze. Cover plants with breathable fabric; add heat if temperatures are forecast to be dangerously low. Remove covers when daytime temps rise and surfaces thaw. Covers and mulches reliably protect against light frost (a few degrees below freezing) and short-duration freezes. For best results, water the soil in the morning before a freeze, focusing on the soil, rather than the leaves, as wet leaves are more prone to freeze damage. During fall and winter, plants generally require less frequent watering, so check the soil moisture before watering to avoid overwatering.