For a greenhouse, there is no need to contrast a local controller and a cloud service as good and bad options. They have different roles. The local controller must perform critical actions near the equipment: stop the pump, comply with limits, read sensors, control lights or ventilation. The cloud is convenient for remote access, reporting, notifications and collaboration.
Problems begin when the cloud becomes the only place where a critical decision can be made. If the Internet is lost, and the pump must stop due to a leak, the system should not wait for an external server. It is safer for plants and water when basic rules are followed locally.
What to give locally
Locally it is worth maintaining automatic watering, emergency stop, water limits, response to leakage, basic ventilation and maintaining fresh data. The controller must understand what to do if the sensor disappears or the Internet is unavailable. For a mini-farm, this is not a matter of convenience, but of reliability.
Local automation doesn't have to be complicated. This can be a ready-made hub, a GrowerHub, Home Assistant controller, or another node. It is important that it follows the rules without constantly accessing the cloud.
What's convenient in the cloud
The cloud is convenient for phone viewing, notifications, reports, team access, backups and updates. If the owner is not near the greenhouse, remote control is needed. But remote control should show what happened locally, and not be the only performer.
For the team, the cloud helps with roles and journaling. The owner sees reports, the operator receives tasks, the observer sees the status. This is difficult to do only locally without external access.
Hybrid model
A practical option is a hybrid. Critical rules and data collection work locally. The cloud synchronizes state, sends notifications and builds reports. If the Internet is lost, the plants are not left without basic care. When the connection is back, the history is synchronized.
This approach is especially important when scaling. The more zones, the more expensive the error of dependence on one external service. The article reliability of automation without the Internet reveals fault tolerance in more detail.
Conclusion
For a greenhouse, it is better to choose not “local or cloud”, but the correct distribution of responsibility. Critical activities remain local, remote access and analytics live in the cloud. GrowerHub should support this model: security near the equipment, convenience and reporting - where the user works.