Giant Spear Lily
Getting started -- A 2-4 quart pot should hold it for at least 6 months. Don't transplant it to too large of a pot. You can use ordinary potting soil, provided that it is well-draining. Transplant gently to avoid damaging the roots. After a year, you can transplant into the ground in mild-winter areas. The soil should be well-draining (clay soils need amending).
Your plant was grown in filtered light, so acclimate it to more light slowly, over the course of a few weeks. I recommend shading it from strong afternoon sun the first month.
Long-term care: Aim to keep the soil about halfway moist most of the time. Don't let the soil dry out completely. You can monitor the soil moisture with a moisture meter probe, which are about $5 at garden shops and home improvement stores.
Feeding -- Feed every 1-2 months using a general purpose fertilizer at 1/2 the recommended dose. If your potting soil contains fertilizer, your plant shouldn't need feeding for the first 2 weeks. Unlike some Australian plants, this one can handle phosphorous, but use a fertilizer with an equal or greater amount of nitrogen ("N") than phosphorous ("P"). Careful not to overfeed your plant.
Repot your plant to a larger container whenever the roots start circling around the bottom of the container or poke out of the holes. As it grow larger over the coming years, repot it to a larger container as necessary.
If you grow it indoors and the humidity drops below 40%, consider using an ultrasonic room humidifier, which you can get inexpensively from home improvement stores and thrift shops.
The Giant Spear Lily is said to handle 5 or 10 degrees of frost, although it's best to give them overhead protection from frost, especially the first few years. In hotter areas, some afternoon shade may be needed, especially if you notice leaf burn.
If you have any questions, feel free to email me.
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