Amaryllis Care Indoors: Watering, Feeding and Turning the Pot

Warmth to start, then cool to hold the flowers

An amaryllis is driven out of dormancy by warmth. Put a freshly potted bulb somewhere at 68 to 75F (20 to 24C), near a radiator or on a warm shelf, and it will break within two to three weeks. The same bulb in a room at 60F (16C) may sit for six weeks and then grow lopsided and slowly. If a bulb has been potted for a month and shows nothing, the answer is almost always more warmth, not more water.

Once the flower stalk is up and the first bud begins to split, the advice reverses. Move the pot somewhere distinctly cooler, around 60 to 65F (16 to 18C), and out of direct afternoon sun. A cool room roughly doubles how long the flowers last: a fortnight to three weeks instead of seven or eight days. Warmth over 75F (24C) with the flowers open pushes them over quickly and stretches the stalk into something floppy.

The stalk elongates fastest in the dark hours, which is why an amaryllis on a warm windowsill with cold nights behind the curtain grows strangely. Bring the pot into the room at night in winter rather than leaving it trapped between the glass and a closed curtain, where the temperature can drop into the forties Fahrenheit (single figures Celsius) and check the bud.

Turn the pot or the stalk leans out of it

An amaryllis flower stalk bends towards light more strongly than almost any other houseplant, and it does it fast. Left facing a window for a week, a stalk two feet (60 cm) tall will be leaning at a noticeable angle by the time the buds open, and the weight of four open trumpets on a leaning stalk drags the whole pot over. Once a stalk has set at an angle it does not straighten again.

The fix is entirely mechanical: give the pot a quarter turn every day from the moment the shoot appears. Do it at a fixed time so it becomes automatic, when you draw the curtains or when you make coffee. A daily quarter turn keeps the stalk vertical and produces a plant that looks the same from every side, which matters because you cannot rotate it for a visitor once it has committed to a lean.

Turning also evens out the leaves. Amaryllis leaves emerge in two opposite ranks, and an unturned plant ends up with one rank stretched and pale and the other short. That is not just cosmetic, since it is the leaves that build next year's flower, and a plant with half its leaf area shaded is storing less.

If a stalk is already leaning badly, support it rather than trying to correct it. Push a slim green cane in at the edge of the pot, well clear of the bulb so you do not spear the basal plate, and tie once with soft twine a few inches below the flowers. One loose tie is enough. Standing the pot inside a heavier outer pot also stops it going over.

Never push a cane in beside the neck of the bulb. The perennial roots run straight down from the basal plate and a cane through them opens a wound that rot gets into. Always insert at the very edge of the pot and angle the cane inward.

Watering: less than you think until the leaves are out

The rule is that water follows growth, not the other way round. A potted bulb with no shoot has almost no roots and cannot use water, so it stays barely damp. Once a shoot is two inches (5 cm) high, begin watering properly: soak until it runs out of the base, then wait until the top inch (2.5 cm) of compost is dry before doing it again. Push a finger in rather than judging by the color of the surface.

In a snug pot in a warm room that usually works out at once a week while the stalk is growing and every four or five days once the leaves are fully out in summer. Those are starting points, not a schedule. A pot that is still heavy and dark at the drainage hole does not need water regardless of the calendar.

Water around the rim rather than into the crown of the bulb. Water sitting in the neck where the leaves emerge is the direct cause of the soft brown rot that takes the crown out. For the same reason, empty saucers within half an hour; a pot standing in water permanently will kill the roots from the bottom up.

Overwatering shows before the bulb is lost, and it is worth knowing the signs. A yellowing outer leaf that goes soft and translucent rather than drying, a sour smell from the compost, and a bulb that gives slightly under thumb pressure at the neck all mean water is standing. Tip the plant out, cut away any brown mush with a clean blade, dust the cut with sulfur or leave it to dry for a day, and repot into fresh gritty potting mix in the same size pot.

Feed hard once the leaves are up

This is the part most people skip, and it is the part that decides whether the bulb flowers again. The flower you are looking at was built last summer. The flower for next year is built by the leaves this coming summer, and the leaves need feeding to build it.

1. Start feeding when the first leaf is fully open Do not feed a bulb that has only a flower stalk and no leaves; there is nothing to use it. Once the first strap leaf has unfurled, begin a balanced liquid feed at the strength on the bottle every two weeks.
2. Switch to high potassium by midsummer From about halfway through the growing season, change to a high-potassium liquid feed, the sort sold for tomatoes, every ten to fourteen days. Potassium builds the flower bud inside the bulb; heavy nitrogen builds soft leaves and a soft bulb.
3. Give it the strongest light you have Full sun for as much of the day as possible. Indoors that means the brightest window in the house. A plant standing in a dim corner all summer will produce leaves that look fine and store almost nothing.
4. Move it outdoors once nights are above 55F (13C) A summer outdoors doubles what most bulbs store. Harden it off over a week in shade before putting it in full sun, or the leaves scorch. Sink the pot to its rim in a bed to stop it blowing over and to slow drying out.
5. Keep every leaf you can Do not cut, tie or shorten leaves for tidiness, and remove one only when it has gone fully yellow. Each leaf lost early is a measurable amount of flower not built. Six to eight healthy leaves through the summer is what a two-stalk bulb is made of.

Records that tell you why it did or did not flower

Keep four dates for each bulb: potting, shoot emerging, first flower open, and the day you started feeding. Add a leaf count taken in late summer. Those five numbers explain almost every amaryllis outcome. A bulb with four leaves at the end of summer very rarely flowers the following season; one with seven or eight almost always does.

Note the bulb's diameter each autumn when you handle it too, measured across the widest point with a tape. A bulb that has grown from three inches (8 cm) to three and a half (9 cm) over a summer has stored well and will flower. One that has shrunk was underfed, under-lit or watered too little, and you can fix a specific one of those next year rather than guessing.