When the leaves start to turn brown and die down, gradually stop watering and allow the plant a resting period, but still keep the bulbs in a warm place. Remember they come from a tropical climate, so a minimum winter temperature of 10 degres C is advisable.
The bulbs will show signs of their approaching rest period in late summer and autumn. Leaves will limp and slowly die back. No new leaves will be produced. At this time, watering the plant must be stopped and the plants allowed to dry out.
By giving the plant a liquid feed during its period of leaf growth, it may not be necessary to re-pot the plant for two or three years, with at the most, a top dressing in spring. However, after three years it is best to change the soil. Re-potting should be carried out in the dorment period, late summer to autumn.
To re-pot the plant, spread newspapers over a table or floor. Turn the pot upside-down and carefully tap out its contents. With the plant removed, carefully separate the earth from the bulb's roots. Remove all the old dried roots together with stale compost.
The bulb will most likely need a larger pot. Hold the bulb over the pot and start filling it with fresh John Innes No. 2 compost, spreading the new roots amongst the compost. Plant the bulb so that the top of the bulb is exposed as before. The top of the compost should be at least 10 mm or 1/2 inch from the top of the rim.
Firm the earth around the plant and water. If the plant is a named variety, label the plant and return it to its growing area.
The bulbs can be bought online under the name of Amaryllis in the UK from these garden centers.