Q. Is it possible to grow dwarf citrus trees indoors in the winter without a greenhouse? I have a large, sunny patio where they could spend the summer months.
A. In the Midwest, dwarf citrus trees make excellent outdoor warm-weather container plants. Most are hardy to 30 degrees and do quite well when provided with warmth, humidity and full sun. To successfully overwinter these plants indoors, take the following precautions:
- In early September, move your plants from the sunny patio to a shaded outdoor spot for several weeks. This will help them to acclimate gradually to less light.
- Check your plants thoroughly for insects before bringing them indoors. Continue to watch carefully for signs of aphids and scale. Lightweight oils and insecticidal soaps will help control these pests.
- Move the plants to a south-facing window or a bright sunroom where they will receive maximum light. Avoid sites close to heating vents or doors that will be opened in cold weather.
- Reduce watering during winter months. Water only when the soil is dry to the touch.
- Provide supplemental humidity. This is essential, especially when the plants are in bloom. Overly dry air will cause them to drop their flowers, resulting in no fruit production.
- Citrus trees are heavy feeders of a high-nitrogen, acid fertilizer during the growing season. Do not fertilize during winter.
- As weather permits in spring, gradually introduce your plants to outdoor conditions