Winter Plant Protection Guide for USDA Zones 7 or Lower
Winter Plant Protection Guide for Planting After August 1st, in USDA Zones 7 or lower.
When planting late in the season, either pot up plants in a container and store in a protected area like a greenhouse, unheated sunroom, unheated garage or, unheated out building with plenty of light. Light should be as close to 50% full sun or brighter.
These are not house plants, so if you keep these plants in a heated house, you will likely kill them. Houses do not provide enough light and maintain too high of temperatures and too low of humidity. Plants need a temperature of 20-40 degrees to experience dormancy so they have vigor in the Spring when temperatures start to rise. Plant outside as soon as your temperatures is over 25 degrees at night in the Spring.
When planting in a container, ensure that your potting soil has very good drainage. 25-30% stone grit (3/8- Pumice, fine crushed gravel, very coarse sand, 1/4 decomposed granite or very fine pea gravel). Then mix in 30% 3/8- fine bark, 15-20% peat, 10% perlite and no more than 10% garden soil or compost. Do not use Big Box or Chain Store potting mixes meant for vegetables, annual flowers or house plants or you will kill your plants with root rot. Even the name brand potting mixes advertised on TV will kill your plants, they are not designed for plants that are not an annual. Do not use any mix that has Moisture Control or water gel.
When planting in a container, fertilizer needs to be low salt. Organic fertilizers like fish, alfalfa, bat guano, kelp, bone meal and rock phosphate are OK, just keep the nutrients balanced, and watch the nutrient level so you do not add too much or too little. Do not use "hot organics” like blood meal or fresh chicken manure under 1 year aged. Chemical fertilizers should say on the label "for container growing". Do not use 10/10/10 or 16/16/16 and similar fertilizers as they are high salt and will burn your plants.
During Winter, water only when the soil dries out or plants can quickly succumb to root rot.