Unity College Dartmouth Greenhouse Week 5

Week 5: 11/21/16-11/23/16; ~17.3 hours left

While this week was a short week, a lot happened so it feels like it was longer.

Photo taken by my co-worker Terry

My older brother came to visit me while I worked this week so it was nice.  He actually came to get his orchid checked out by the Greenhouse workers.  It was a Dendrobium sp hybrid.  The orchid had not flowered in years and would only occasionally produce new growth.  My co-worker Terry helped diagnose its condition and requirements for flowering.  She is very knowledgeable about orchids as she is usually the one in charge of their upkeep.  What was determined was that the orchid needed to have a winter dormancy.  All the species that makes up the hybrid have to go through a dormancy period where you stop watering and fertilizing of the plant for the winter months.  The hope then is that the orchid would then bloom in the spring once the temperatures had warmed and the light had increased.  After this year's dormancy, the orchid should be repotted and a change of substrate.  As I may have mentioned before most if not all orchids are epiphytes (grow on other plants or surfaces that are not soil).  They do not live in soil so they require a substrate that has a certain level of aeration. When the substrate starts breakdown, it starts to choke the orchid.  This particular orchid hybrid was potted with coconut husk substrate.  Coconut substrate degrades faster than substrates like fur bark. Once the dormancy is over switching to fur bark would be best. Orchids also like to be pot-bound rather than 'over-potted' so it needs a smaller and taller pot.

According to my brother, the flowers look similar to these Dendrobium here in shape and size.

Mainly this week I finished clipping down the plants in the Tropical Room. The Yam vine ended up winding its way up past the sun screen and around the water pipes and the hydraulics in the door. It was like untangling rope but more difficult as the vines branched out every which way.

While using a ladder to clip can be dangerous, the fact that there were so many support structures around me allowed me to maintain my balance relatively easily while being in unusual positions.  To maintain those positions one must move slowly and incrementally, and be very aware of the pressure exerted on anything.  One cannot put too much pressure in one place.  I usually try and keep my pressure on the sides of structures, not fully downwards. And as always REMEMBER TO BREATHE!

Photo taken by my boss Kim

I had to trim back the philodendron in the Tropical Room (Philodendron erubescens). We have two types of philodendrons in the Greenhouse.  Both are very large and have a tendency to grow where ever they can get away with. Unlike vines, they don't tangle around themselves nor have modified leaves to grab with.  In order to climb, they use whorls of adventious roots (above-ground roots that are used for purposes other than absorbing nutrients) to grab at and support themselves as they grow.  In the case of our greenhouse, it means climbing the walls and structural supports of the Tropical Room.


In order to cut it down to size, I had to saw two of its stems off.  The stem itself was very fibrous and dense. It kind of reminded me of a combination of bamboo and rhubarb.

Each fresh leaf scar will produce a vibrant red and pink sap that beads profusely. It stained a little on skin so I could see it being used as a natural dye.


Recently most of the citrus plants have been producing fruits, so the Subtropical room has had a very pleasant smell this week. The Greenhouse has a lot of citrus species and hybrids; from Lemons to Sweet Limes to Kumquats and a couple of hybrids that I had not even heard of.  Some of the major producers in the Subtropical Room were the Lemons.  Most of the lemon varieties we have are not the lemons we typically think of; ie the "store-bought-lemon" (Citrus × limon; citrus hybrid).  They are sweeter than store lemons but still sourer than an orange.  I found out to my surprise that most of the edible citrus fruits that we think of are in fact a series of hybrids that were bred from other older species like the citron and the mandarin.  Unlike apples which are multiple varieties and subspecies of one original species; citrus fruits are hybrids on top of hybrids.

Meyer Lemon (Citrus × meyeri; citrus hybrid). It is roughly the same size as a store-bought lemon, maybe a little smaller.  The tree itself was fairly laden with them so my boss gave me some of the ripened fruit to me for Thanksgiving.  I was very touched by the gesture as they were grown from the Greenhouse.  The smell of the rind was very strong even before peeling.  The rind itself was thinner than a typical lemon but still harder to peel than an orange.  the flavor was much stronger than that of a grapefruit but still had a particular sweetness to it.  It was still very potent so I could only eat it one section at a given time. This made it very good in teas.

Pondarosa Lemon (Citrus limon × medica; citrus hybrid).  This fruit was huge, especially when it was compared to the size of the tree it was on (the tree was only at most ~3 feet, including the pot). Unlike with the Meyer Lemon the fruit took a long time to ripen or at the very least a long time to stay on the tree.  You can never be quite sure unless you pick it.


A banana 'tree' flower inflorescence (a group of tightly packed flowers like lilacs) (Musa acuminata).  The inflorescence does not flower all at the same time, the lower flowers bloom first and gradually bloom upward.  You can see the fruit starting to form at the base of the inflorescence.  This species of banana produces a dwarf version of the cultivated banana we are used to.  It is actually thought to be a precursor of that cultivar.

The Scarlet Ball Cactus (Parodia haselbergii) finally bloomed!  It had not bloomed since I started working here except for a few dead blooms that had not been removed.  I had removed the dead blooms before any new buds came in.  My hypothesis was that the dead blooms were preventing the cactus from creating fresh blooms and by removing them it allowed new blooms to come in.  Often if a plant has gone through its seeding stage and the seeds are allowed to stay on the plant, it will not have the need to flower as the next generation is "secure" so to speak.  If you remove the flowers before they seed, it triggers the plant to 'think' it is under stress and will produce more flowers as a response.

Have a good week! Happy Thanksgiving weekend!