This question (which is, in fact, a group of related questions) is partially explored in Transforming Mythic Europe. In my opinion, a good philosophical answer is the following.
Magi mostly care about magic.
Through magic they can achieve all modern technology achieves and more, and more easily and reliably. And they can be fabulously rich. So a magus seeking a solution to a problem will first think "can I purchase an existing mundane solution, however expensive"? If and only if the answer is no, he'll think "can I obtain a good solution through simple personal magics"? If and only if the answer is no (which is very, very rarely the case) he'll think "can I develop a new technology"? This is particularly true since disrupting the mundane world is frowned upon as a source of endless problems.
So yes, a magus can make a ReTe railgun ... though really, isn't is safer and easier to just sling big boulders yourself? A magus could think of printing presses and moving types ... but really, why bother when you can easily create enough wealth to support all the mundane scribes you need? Why fountain pens, when a little ReAn/He/Te can ensure your quill writes just as beautifully if not more? In this sense yes, I do agree that most magi would not make mundane glass for a greenhouse, they'd use a D:Ring effect to make the roof and walls transparent - without the risks associated to the fragility of glass.
I am definitely not an expert, but I have a feeling - it is not stated in the Species chapter of the Jerbiton House, so I might be wrong - that iconic species do not carry heat (will it be the haptic species ?). So a one-way, transparent stone roof, although perfect to protect you from indiscreet spy and solid as rock, will only provide a cold light, so heat will have to be provided. That's the only reason why a mage would decide to go with glass panel versus transparent stone.
At the end, my mage will go with the Orb of Greek Sunlight, since it will guarantee him that his plants will get the proper sunlight (heat and light). The green house was a nice-to-have that will have to wait until he had better understanding of agriculture, and various Arts.
An alternative to glass given the location, is to use sheets of ice. Ice can form in natural sheets on lakes, be flat and very clear, so a ReAq effect built into a window frame to keep water within the fram in a solid state would work. The solidity of the ice I think can be divorced from its temperature, so it would not necessarily cool the interior.
For other devices, something to replicate a talking to plants spell to see how they are that can be given to mundane gardeners so they can tend appropriately while the maga is elsewhere.
Longterm would be a massive device that (with a high enough Artes Liberales) translates the moods of the plants into sounds, so one can sit in the garden and listen to the music of the plants.