Why is a potted amaryllis only sends up leaves and not flower? This is the second year this has happened. I’ve been following Sonia Day’s instructions from The Real Dirt, Toronto Star, which she details precisely.
Amaryllis require a minimum of 8 weeks cooling off period between 4 -10 degrees Celsius, to produce flowers. They also need to be stored in a dark place. They can be bagged in thick brown paper and stored in a refrigerator, but don’t store apples in the same fridge as this can sterilize them. You could also store them in your garage, as long as it doesn’t get below 4C. After two to three months of cooling off you can pot your bulbs. Soak the bulbs in warm water for two hours prior to placing the bottom two thirds of the bulb in a nutritious potting compost. Store bought potting soil is ideal. Press the soil down firmly, so that only one third of the bulb is above soil level. Water sparingly and place in direct light in a warm spot (at least 20 degrees Celsius) The bulbs need the light and heat to stimulate flower growth. Overwatering in the early stages of growth can rot the bulb. Continue to water sparingly until the stem appears. Increase watering as bud begins to appear. Fertilize monthly with liquid fertilizer (a 20-20-20 blend is good) It takes about 8 weeks for Amaryllis to bloom from potting time. Rotate the pot to ensure all sides of the plant get adequate light, and to encourage straight stem growth.
If a bulb doesn’t flower after all these steps have been taken it may be undernourished and unable to produce a flower for the season. Continue to feed and water until the leaves turn yellow and wither as the plant goes into dormancy. This will allow the bulb time to replenish its stored nutrients for next season. Trim off the dead leaves and begin the cool storage phase again. Your bulbs should be firm like onions prior to planting in the spring. Good luck!