Question
Hi Wayne,

I purchased a Phalaenopsis orchid at "Lowes" garden center 9 days ago with six full blooms along the upper part of the one main orchid stem. The blooms began to fade 4 days ago and was told by a nursery to pinch the white, thin bloom stems off near the main stem which I did and it might rebloom. No sign of reblooming near the six pinchoffs yet but further down from the previous bloom stems, (on the main stem), there are 4 swollen nodes,(I think I heard them called bracks), equally spaced on down to the base of the plant. The upper two nodes are swollen and have a purplish paper thin leaf-like sheathing tight over them with a green BB sized bump appearing now underneath this purplish sheathing on the node. The green spot almost feels like the hard head of a pimple. Is this a sign I might have two nodes preparing to bloom?
The two lower nodes have a purplish-brown sheathing but are less swollen, almost flat, with nothing green underneath. Since the upper two of the four nodes below the previous bloom portion of the main stem appear more energetic than the lower two nodes on the same main stem, does this mean that orchids generally tend to send their nourishment towards the upper nodes of the main stem?

I've also heard that cooler air can sometimes shock an orchid into bloomong or reblooming. Would placing an ice gel pak near the base of the plant, not touching the plant, or bringing an ice gel pak near a potential bloom node cause the nose to send out a bloom or bud forth earlier?

Thank you very much!

Mark P.

Answer
Mark, thank you for your interesting questions.  I have not seen a good explanation as to why the upper nodes tend to be the ones most likely to produce flower spike branches. Clearly, mother nature has programmed the upper nodes on green, old flower spikes to behave in this manner. It may be that this feature has been naturally selected because flowers on the upper part of the plant are most visible to pollinators and hence most likely to be pollinated. As growth hormones become active in the upper node (s), it (they) produce hormones that inhibit similar activity in the lower nodes.  This helps to conserve the plant's energy while maximizing the pollination prospects. You may want to remove that part of the old flower spike above the uppermost node showing some activity to prevent similar activity in any nodes above that as such activity would inhibit growth in those nodes now showing some activity.  It is generally recommended to cut a green flower spike above the third node for this reason.  Be prepared that any node has the potential to produce either or both a branch in the flower spike and/or an entire new plant (called a keiki).  It appears that keiki production is more likely under low light conditions and floral branches under higher light conditions.  Bracts are coverings of the nodes to prevent damage to the merristemmatic tissue responsiblefor new growth at that point.

The only potential influence of cold on phalaenopsis flowering is as a stressor where the plant may flower as a survival mechanism.  I'm convinced that this is not the best way to induce flowering as it might affect overall plant health and could play a role in root rot or mesophyll collapse. Some commercial growers providing phalaenopsis to Lowes or Home Depot will retrieve plants that have finished flowering. They then remove that portion of the old green flower spikes above a node and get a second flowering in the same year and same temperature range. Fairly bright light can indcue or enhance flowering. Most phalaenopsis flower in the spring as the day length increses, so day length can play a role in flowering.

You may want to consider repotting the plant in a fir-bark based orchid pottting mix as this is generally recommended following flowering. You can judge this by the overall health of the leaves.  Plants that are in moss or a degraded potting mix can go downhill quickly and, by the time leaves start yellowing or drooping, root damage has already occurred.  I have purchased many plants from Lowes and Home Depots and there is no consistency in the shape of the potting mix at time of purchase. I recently talked to the nursey person at a Home Depot at an Ohio Home Depot after finding water standing in the pots of many plants.  He said that the supplier told him to water them twice a day.  Generally, the interest in these nurseries is to get the plants out of the door as soon as possible without consideration for the implications of growing the plants long term.