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How to overwinter tropical plants indoors
10 key tips for successful overwintering
Q: I have two Mandevillas that thrived on my balcony all summer. Now that cold weather is approaching, I've moved them indoors to bright spots, but they're dropping and wilting leaves. How can I keep them healthy until spring? Should I fertilize them? Can Mandevillas grow indoors year-round?
A: First, keep in mind that the plants we call "indoor plants" or "house plants" are all tropical. However, not all tropical plants are suitable for indoor living. Some, especially shade-loving ones, thrive in indoor conditions, which is why we refer to them as "house plants" (philodendrons, monsteras, calatheas, peperomias, and many others, including some succulents). Others are less adaptable to the lower light and humidity typical of indoor spaces, but with a little extra care, you can overwinter them inside and move them back outdoors in spring. Mandevillas are no exception! Even tropical trees, including fruit trees, can tolerate a few months indoors if given the right conditions for semi-dormancy. Below are the 10 key tips for successfully overwintering tropical plants indoors.
1. Maximize Light: The more light, the better. There's no such thing as too much indoor light. If windows aren't enough, use LED grow lights, which stay cool and won't dry the air. Rotate plants every few days to prevent uneven leaf loss.
2. Reduce Watering: Less light and cooler temperatures mean plants need less water. Allow the soil to dry between waterings, and avoid overwatering - combination of cold + wet is especially harmful.
3. Maintain Moderate Temperatures: Most tropicals are happy with daytime temperatures around 75F and nights at 50-60F. In sunrooms or greenhouses, some can handle 45F if watering is kept to a minimum.
4. Boost Humidity: Avoid placing plants near heaters or vents that dry the air. Misting daily helps, or place pots on trays filled with water and pebbles to raise humidity around them.
5. Monitor for Pests: Check leaves weekly to catch insect problems early, as pests can cause serious damage or even kill the plant indoors.
6. Fertilize Smart: Use ONLY liquid, amino-acid-based fertilizers like Sunshine Boosters throughout winter; they won't burn roots since their dosage adjusts with reduced watering. Avoid dry, granulated, and EDTA-based fertilizers during winter and dormancy.
7. Use Micro-Nutrients: Along with macro-elements (fertilizers), supplement with micro-elements like Sunshine Superfood and bio-stimulants such as Sunshine Epi to build strong plants with robust immune systems, better able to withstand unfavorable conditions and resist diseases.
8. Hold Off on Pruning: Leaf drop and leggy growth are normal responses to winter. Wait until spring to prune, when new growth starts, to encourage branching and healthy foliage.
9. Don't Repot Yet: During dormancy, roots slow their growth. Repotting too soon risks root rot. Wait until spring when new growth appears to transplant into a larger container. Typically, roots grow in proportion to the above-ground parts.
10. Let Them Rest: Winter is a natural resting period. Avoid forcing growth - your plants will reward your patience with vibrant leaves and flowers when spring returns.
