If you already all the hardware working to monitor and control your green house, then you only need to add a layer of software that will allow you to publish it to the web or trough VPN.
I strongly suggest you to use VPN in order to make your project safer. if not, you will need to have another software layer to include the security encoding like AES 256. AES Security will be a real head heck to implement for you. so use VPN... so much easier. Also most of the router will allow you to configure VPN without having the huge knowledge on security.
If you use another computer or tablet that run on Windows or Linux (depending of your version of LabVIEW) you can stay in LabVIEW and use VI-Server calls. If not, you will need to implement html layer to your code or TCP-IP protocol that you can determine as you wish. The you will need to develop the web client to communicate trough this TCP-IP protocol.
Another idea that I prefer, is the use of Database. This allow you to keep the history of what happen in your green house. Moreover, secure web application can be developed in the language of your choice to connect to this database. But this is another level of knowledge.
Exception of the VI-Server approach, this project will require you to increase dramatically your level of knowledge on another IDE and or technology.
I think once you design your application on paper, if you post it, many people will be able to help you on the specific impediment you will encounter.
Benoit
