What does overwintering plants mean?

Overwintering plants means keeping a tender plant alive through a cold season it would not survive outdoors. You do this by moving it indoors, wrapping its stems, or mulching over its crown before the cold arrives. The method depends on the plant's cold limit and how cold your yard gets.

When should you start overwintering plants?

Start when the adjusted overnight low in your yard approaches the cold limit of your most tender plant. Tender plants have to come in before the first frost, so a few days of margin helps. In our own garden the effective first frost sits around September 30 once our offset is applied, weeks ahead of the published October 22.

Which plants need overwintering?

Any plant whose cold limit sits above your yard's real low needs overwintering. Tender annuals and peppers die near freezing, tropicals like bananas need a frost-free dormant spot, and half-hardy perennials such as some salvias survive in place under mulch. Group each plant by its limit so you know which to act on first.

How do you overwinter potted plants?

Hose off the foliage, check for pests, then carry the pot into the brightest cool room you have before the first frost. Cut back leggy growth and water far less, because a dormant plant drinks little. Keep it cool and on the dry side so the roots do not rot through winter.

October 9, 2026

How to start overwintering plants by your yard's real low

Overwintering plants means keeping a tender plant alive through a cold season it would not survive outdoors. Whether you move a plant indoors, wrap it, or mulch its crown depends on the plant's cold limit and the real low your yard hits on the coldest nights. The zone map gives neither number. Below are the steps we follow and the night we act.

Step 1. Find your yard's real low

The zone map gives a regional average. It does not tell you the temperature in your yard tonight. Dense cold air slides downhill after dark and settles in the lowest corners of a yard. Walls and paving hold daytime heat and release it after dark. These effects push your low away from the forecast. In our own garden the station reads 7°F colder than the forecast low, and our first fall frost in 2025 landed on October 3, nearly three weeks before the published first-frost date of October 22.

Free users enter this offset by hand in Settings, where negative means colder. A Pro connected station learns it after about 14 days of overlapping outdoor readings. Either way the offset shifts the forecast lows and the frost dates the app shows you. You can see how your area compares with nearby stations using the microclimate checker.

Step 2. Sort your plants by their limit

A plant dies in winter when ice forms inside its tissue and ruptures the cells. The temperature that triggers this differs by plant. Group yours by cold limit so you know which ones need action first.

Tender, dies near freezing. Chillies and peppers, basil, coleus, and most summer annuals. Move or lose them before the first frost.
Tropical, kept dormant indoors. Bananas, brugmansia, tender fuchsias. Wheel them in before nights drop into the 40s °F.
Half-hardy, protected in place. Many salvias, some dahlias, young figs. Mulch the crown or wrap the stems.
Hardy, left alone. Garlic, strawberries, and anything rated below your real low. Leave them out.

See winter care for banana plants and overwintering chilli plants for two worked examples.

Step 3. Pick the night

Start when the adjusted overnight low approaches the limit of your most tender plant. For us the effective first frost sits around September 30 once our offset is applied. The published date of October 22 runs almost three weeks late. A frost alert fires for every garden, free and Pro, on the afternoon before a night at or below your threshold, so you get a prompt to act. Do the move a few days early for tropicals that resent cold roots.

Step 4. Move, wrap, or mulch

Potted plants are the easiest to save, because you can carry them out of the cold.

Hose off the foliage and check for pests before the pot crosses the threshold.
Cut back leggy top growth so the plant fits its winter spot.
Set it in the brightest cool room you have, and water far less, since a dormant plant drinks little.
For in-ground tender plants, pile mulch over the crown or wrap the stems with fleece once the cold arrives.

What can go wrong

The real low tells you the air temperature at sensor height, not how cold a pot's rootball gets. A pot sitting above ground loses heat on every side, so its roots can freeze while the same plant in the ground survives. Group pots together and lift them off cold paving to slow the loss.

Bringing a plant indoors moves its pests indoors too. Inspect the foliage and soil before the pot comes in, and again a week later, so an infestation does not spread to your houseplants.

Open your plant list, write each one's cold limit beside it, then set your offset so the app shows you the night each plant has to come in.

Common questions.

What does overwintering plants mean?: Overwintering plants means keeping a tender plant alive through a cold season it would not survive outdoors. You do this by moving it indoors, wrapping its stems, or mulching over its crown before the cold arrives. The method depends on the plant's cold limit and how cold your yard gets.
When should you start overwintering plants?: Start when the adjusted overnight low in your yard approaches the cold limit of your most tender plant. Tender plants have to come in before the first frost, so a few days of margin helps. In our own garden the effective first frost sits around September 30 once our offset is applied, weeks ahead of the published October 22.
Which plants need overwintering?: Any plant whose cold limit sits above your yard's real low needs overwintering. Tender annuals and peppers die near freezing, tropicals like bananas need a frost-free dormant spot, and half-hardy perennials such as some salvias survive in place under mulch. Group each plant by its limit so you know which to act on first.
How do you overwinter potted plants?: Hose off the foliage, check for pests, then carry the pot into the brightest cool room you have before the first frost. Cut back leggy growth and water far less, because a dormant plant drinks little. Keep it cool and on the dry side so the roots do not rot through winter.

Related guides

Free planting tools

When to plant shows the last date to sow each crop before your fall frost.
Microclimate checker shows how much colder or warmer gardens near you ran than the forecast low.
GDD estimator adds up a typical season's heat and shows which crops can ripen where you are.