Gadenin日本語Get the appFirst decide whether the spike is still alive
Before you reach for the pruners, look at the spike itself. A living spike is green, firm and slightly glossy along its whole length, and it will often still have a green tip. A spent spike turns yellow, then straw brown, then dry and hollow, usually starting at the tip and working down. Which of these you have decides what is worth doing.
A spike that has gone brown all the way down has nothing left to give. Cut it off at the base, about half an inch (1 cm) above the point where it emerges from between the leaves, and forget about it. Leaving a dead spike attached does no harm but no good either, and the dry hollow stub is a comfortable place for mealybugs to hide.
A spike that is still green after the last flower drops is a genuine choice, and the rest of this guide is about that choice. There is no single right answer. What you should do depends on how vigorous the plant is, and on whether you would rather have some flowers soon or better flowers later.
Judge the plant, not just the spike. A healthy moth orchid ready to be pushed for a second flush has at least three or four firm, fat leaves and a pot full of plump silvery-green roots. A plant with two limp leaves and half a dozen live roots should not be asked to flower again; cut the spike right off and let it rebuild.
Where to cut, and what each cut does
A flower spike carries a series of small triangular bracts spaced along its lower half. Under each bract is a dormant node, and each node holds a bud that can either branch into a new flowering side shoot or, occasionally, grow into a keiki, a small plantlet. Cutting the spike just above one of these nodes removes the hormonal dominance of the tip and can wake the node up.
Count the nodes from the bottom. The convention is to cut about half an inch (1 cm) above the second or third node from the base, which leaves enough spike to work with and puts the new branch at a sensible height. Cut with a sterile blade, straight across, and cut cleanly rather than crushing the stem. Sterilize the blade in flame or with rubbing alcohol between plants, because virus is transmitted on cutting tools.
| Where you cut | What usually happens | When to choose it |
|---|---|---|
| Just above the second or third node | A side branch flowers in 8 to 12 weeks | Vigorous plant, you want flowers soon |
| Just above the node below the lowest old flower | A short branch with a few flowers | Spike is long and you want a tidy plant |
| At the base, half an inch (1 cm) above the leaves | No more flowers this cycle, strong new growth | Tired plant, or you want a full spike next year |
| No cut, spike left whole and green | The tip may extend and flower again on its own | Spike still green with an active growing tip |
| Any cut on a brown, hollow spike | Nothing. The spike is dead | Never. Remove it at the base instead |
How a node branches, and how long it takes
After you cut above a node, nothing visible happens for several weeks. Somewhere between four and ten weeks later, the bract lifts and a small green point pushes out from under it. That point becomes a side branch, and it takes another six to eight weeks from there to open its first flower. Reckon on two to three months from cut to bloom in good conditions, and be patient rather than cutting again in the meantime.
The branch will carry fewer and smaller flowers than the original spike. That is normal and not a sign of ill health. The plant is flowering on stored energy that it built up before the first flush, and the second flush is always the lesser one. A plant asked for two or three branches in a row will eventually flower itself into decline, which is why growers alternate: push for a branch one year, cut to the base the next.
Sometimes the node produces a keiki instead of a branch: a small plantlet with its own leaves, and eventually its own roots. This is more common in warm humid conditions and on plants that have been fed nitrogen heavily. Leave a keiki attached until it has two or three roots at least two inches (5 cm) long, then cut the spike either side of it and pot it in fine bark. It will take two to four years to reach flowering size.
If nothing happens after twelve weeks, the node is not going to move. Cut the spike off at the base and turn your attention to leaves and roots instead.
Do not seal, wax or paint the cut end. A clean cut on a healthy spike dries on its own in a day. Sealing traps moisture at the cut and is a common route for rot to enter the spike.
Reblooming needs cool nights, not more fertilizer
The single most common mistake after flowering is to reach for the feed. Extra nitrogen after a flush produces exactly what nitrogen produces: leaves. A plant fed hard in a warm room grows fine broad foliage and stubbornly refuses to make another spike, and the owner concludes that the plant has stopped flowering when in fact it has never been asked to.
What actually initiates a fresh spike from the base of the plant is a drop in night temperature. Roughly two to four weeks of nights around 55 to 60F (13 to 16C), with days still in the seventies F (low twenties C), tells the plant that the season has turned. In a house held at one temperature day and night all year, that signal never arrives. This is why the same plant flowers every year on a cool porch and never in a centrally heated lounge.
So the plan after flowering is simple. Cut according to the table above. Feed at half strength while the plant is in active leaf and root growth, and stop when growth slows. Then, in autumn, give it the cool nights. A brand new spike coming from between the lower leaves, rather than a branch off an old one, is the reward, and it will always be the better display of the two.
The weeks after the flowers drop
The period straight after flowering is when a moth orchid does most of its growing. A new leaf usually starts to unfurl from the center within a few weeks, and fresh roots push out from the stem. This is the phase that pays for next season, so treat it as the important part of the year rather than the boring part.
Keep watering by the roots as usual, letting the medium approach dryness and then soaking it through. Feed weakly and regularly while a new leaf is visibly expanding, using a balanced orchid fertilizer at a quarter to half the strength on the label, and flush the pot with plain water every fourth watering to stop salts building up in the bark.
This is also the natural moment to repot if the plant needs it, because the bark has broken down or roots are climbing out everywhere. Repot in the weeks after flowering rather than while a spike is in bud, when disturbance causes buds to drop.
Finally, take the stake out, or at least loosen the clips. Most plants are sold tied hard to a stake that keeps the spike upright and the plant looking uniform. Once the flowers are gone the stake serves no purpose, and clips left in place for a year cut into the tissue as the spike thickens.
What to write down
Record the date the last flower dropped, where you cut, and how many nodes you left. Then record whether anything came from that node and how long it took. Two or three seasons of that turns a guess into a fact about your own plant: some clones branch readily from the second node, others never branch at all and are only worth cutting to the base.
Note how long the flowers actually lasted, from the first opening to the last drop, and note the temperature of the room they were in. Cooler rooms hold moth orchid flowers for three months or more, while a warm room shortens the display considerably, and the record makes that trade-off visible when you decide where to put the plant next time.
Keep a note of when each new leaf starts and finishes expanding, too. A healthy mature moth orchid makes two or three new leaves a year. If your record shows only one, the plant is short of light or root, and no amount of cutting spikes in the right place will fix that.