Sorry I have been busy with thanks giving preps, so this blog post is late!
At the greenhouse we have multiple substrate and soil type based on the requirements of the plants, the substrates are usually used for the orchids and other epiphytes. We have 3 major soil mix types: Metro Mix (for the general unspecific plants); Cactus Mix (for the xerophytes and plants that require high drainage); Tropical Mix (for the plants that are in the Tropical Room).
This week I got to learn how to mix up a new batch of the cactus mix soil, which I was very excited about. Since being put in charge of the Xeric Room (ie Cactus Room), I have done a lot of re-potting and dividing and so the cactus mix had become very depleted. Each soil mix has their own particular recipe specific to the plants that are to be potted. Cacti need soil that is well drained and some what alkaline ('basic', ie acids and bases).
The bin that the cactus soil mix is held in.
To measure out the larger amounts of ingredients we usually use metal basins that each about half a bushel. I first measured out "garden variety" potting soil mix (I made a pun there) as the base for the mix. Then I added a decent amount of sand (I don't think that it matters what type of sand, just the size of the particles). The sand adds drainage to the soil and matches the natural soil type that cacti grow in.
The next two ingredients are used to help with the drainage allowing the roots to dry out
Perlite is a volcanic rock that is very similar to pumice but is a brilliant white. It is very chalky and dusty. Turface is a gritty gravel like mineral that has a reddish coloration. According to my boss it has been used in athletic fields for drainage and traction (ie the reddish-brown areas of a baseball field). I had to ware a face mask while handling the perilite and turface due to the dust they created. By themselves the aren't particularly toxic or caustic, it is the actual inhalation of the dust they create that is harmful. As a final additive we add a small amount of the pellet fertilizer, 10-10-10 and Calcium Carbonate (CaCO3) because cacti usually like the soil to be a little more alkaline.
Perlite (left) and Turface (right) I was unable to take pictures of the process itself as the dust would damage the camera.
When mixing up the soil I would use a metal dust pan to fold the layers together on the prep table in the prep room. After mixing, I was able to re-pot some of the plant
It is very satisfying being able to not only re-pot plants your self but mix up your own soil as well.
This Wednesday was the last Botanical Illustration Class that was to be held during my stay as an Intern. I had not known this earlier but Dartmouth College worked on a Trimester Schedule not a Semester schedule. The students classes ended this week and they would restart after New Years. This also effects the other community events that the College offers during the semester. I am somewhat familiar with the trimester method as my older brother got his bachelors degree at a college that had a similar set up.
During the class we mainly did a wrap up of what we had learned previously and the teaching artist's work. Many of them were on local Vermont spring ephemerals such as ladyslipper orchids and crocuses. We went on to discuss in detail the botany of the native ladyslippers. One in particular I had not known about or realized was so local was the Yellow Ladyslipper or Cypripedium parviflorum (it was originally included with the species C. calceolus, which is a European species). The specific epithet "calceolus" means "calcium rich" and refers to the fact that the orchid only grows in alkaline soils. Local orchids are unique in their germination methods. Unlike other seeds, orchid seeds have no extra nutrition added (ie no endosperm or pericarp). To germinate those seeds, mycorrhizal fungi are require to be present in soil. This mutualistic relationship allows the orchid to gain enough nutrients from the fungi to grow.
We also were reminded to practice regularly even though there will be no more class. That is the only way we will improve. Everyone in the class was very kind and helpful allowing me to take part even though I am not an OSHER member or signed up for the class. I hope to see them in the future outside of the class.
As with any greenhouse, we have to keep control of the growth of the plants so they do not strangle the other plants or the greenhouse itself. Many of the plants in the different rooms ended up strangling and choking the equipment and pipes. Since it got to the point where the climate controls for the rooms were getting effected, I was tasked to clip back those vines and plants so that they don't choke the greenhouse. I worked mainly in the entry room, main hallway, tropical room and cacti room. It was very difficult work as I had to use a ladder and many of the vines had gotten seriously tangled within each other and the greenhouse infrastructure. The wax plants were probably one of the worst to work with as not only did they have a thick waxy cuticle and milky stick sap that is almost impossible to get off. I make a specific point that there were enjoyable parts of this work as I was able to view parts of those plants that otherwise were hidden.
A Bougainvillea vine blossom tangled up in one of the misting pipes. There were a good amount of thorns on this plant so it was very tricky to remove.
Two views of the Bower Vine (Pandorea jasminoides), the vine itself (left) and a flower (right). Many of the vines had escaped up into the sun screens to get more direct sunlight.
Have a great break!