Gadenin日本語Get the appThe year in four phases
Keeping a poinsettia for a second winter is not difficult, but it is unforgiving about timing. The year splits into four phases, and each has one job that determines whether the next phase works. Miss the hard cut in spring and you cannot build a bushy plant over summer. Miss the start of the dark treatment in autumn and there is no way to catch up.
Everything below is written by season rather than by date so it reads the same in either hemisphere. Anchor the whole year on the date you want the color, and count back ten weeks from it for the start of the dark treatment.
| Phase | Season | The one job that matters | Watering |
|---|---|---|---|
| Display | Midwinter | Keep it above 55F (13C) and out of drafts | When the surface dries, empty the saucer |
| Cut back | Early to mid spring | Take every stem to four to six inches (10 to 15 cm) | Barely moist until new shoots appear |
| Grow | Late spring to late summer | Pinch the tips twice to build a bushy plant | Freely, plus half-strength feed fortnightly |
| Color up | Mid autumn to early winter | Fourteen hours of unbroken darkness nightly | Normal, checked before covering it each evening |
Midwinter: hold the display
Nothing needs to be done to a plant in full bract except to stop it being killed. Hold it at 60 to 70F (16 to 21C), give it the brightest window you have, keep it off cold glass overnight, and away from doors, heating vents and ripening fruit. Do not feed it and do not prune it.
The single practical action is to check the sleeve or foil came off and the saucer is emptied after every watering. A poinsettia in a warm room in a sealed sleeve is on a two-week clock.
Spring: cut back and start again
Once the bracts dull and start dropping, the display phase is over and the plant goes into its growing year. This is the phase people skip, and skipping it is why second-year plants look leggy.
- Cut every stem back hard Down to four to six inches (10 to 15 cm), cutting a quarter inch above a leaf node. Wear gloves, the cut stems bleed white latex. Leave three or four nodes on each stem so it has buds to break from.
- Reduce watering while it is bare A leafless plant uses very little. Keep the compost barely moist until new shoots are an inch long, then return to normal. More cut-back plants are lost to overwatering at this point than to the cut itself.
- Repot if it is rootbound Once new growth is properly away, move it up one pot size into a free-draining mix. Only go one size, and only if roots were circling the outside of the old root ball.
- Move it to the brightest spot you have New shoots grown in poor light come thin and stretched, and no later work fixes that. This is the phase where light does the most good.
Summer: build the plant
This is the growing phase and the one that decides how big next winter's display will be. Once nights are reliably above 55F (13C), put the plant outdoors in dappled shade, moving it into brighter light gradually over a fortnight. It will grow far harder outside than in.
Feed a balanced liquid feed at half strength every two weeks and water freely, because a plant in full growth in warm weather dries fast. Pinch out each growing tip when a shoot has made four or five leaves, then pinch the resulting shoots when they in turn have four or five leaves. Two rounds through the summer take a four-stemmed plant to twelve heads or more.
Stop all pinching at least eight weeks before the dark treatment starts. Bracts form on shoot tips, so a tip pinched too late in the season has nothing left to color.
Autumn: the dark treatment
Bring the plant back indoors before nights fall below 55F (13C), checking the leaf undersides for pests first. Then begin the routine that produces the color: fourteen hours of complete, uninterrupted darkness every night, and ten hours of bright light every day, for eight to ten weeks.
Stop feeding as the treatment begins and keep watering normal, checking the compost before you cover the plant each evening rather than after. Expect the first pink flush in the top bracts after four or five weeks. When the color is full, stop the covering and move it to its display position for the winter.
| Week of treatment | What to expect | What to check |
|---|---|---|
| Weeks one to three | No visible change | That the dark place is genuinely dark |
| Weeks four and five | First pink tinge at the top | Enough daytime light, it is easy to skimp |
| Weeks six to eight | Color spreading and deepening | Temperature holding at 64 to 70F (18 to 21C) |
| Weeks nine and ten | Full color, true flowers still closed | Stop covering, move it to display |
What to record through the year
Four dates carry the whole cycle and each one directly informs a decision twelve months later. Write down the date of the hard cut back, the dates of each summer pinch, the date the dark treatment started, and the date the first pink appeared.
From those you learn your own plant's timing: whether you cut early enough to fit two pinches in, and how many weeks of darkness your conditions actually needed. Add the date you moved it outdoors and back in, plus the night temperature you were comfortable with, and the following year becomes a matter of following your own notes rather than reworking it from scratch.