homeassistant will be your easiest and most reliable path.
Lots of options if you want to roll your own.
Home automation is the residential extension of building automation.
It is automation of the home, housework or household activity.
Home automation may include centralized control of lighting, HVAC (heating, ventilation and air conditioning), appliances, security locks of gates and doors and other systems, to provide improved convenience, comfort, energy efficiency and security.
Warning: Working with electricity can result in injury, property damage, or even death if it is not done properly. Please keep this in mind while assisting others. If you are not sure about what you are doing, hire a licensed professional.
homeassistant will be your easiest and most reliable path.
Lots of options if you want to roll your own.
have you considered using OpenHAB for your greenhouse automation? It's highly customizable and can work with wired sensors and triggers. You can set up a dashboard to monitor the environment remotely and integrate with various devices for irrigation and HVAC control. It's worth checking out for your project!
There are many projects for doing this sort of thing.
Home Assistant can do the job but it's a bit of using a swiss army knife when you just need a hammer.
Node-red on a pi can get you the automation plenty of gpio to mqtt bridges even pwm to SSR to control ac fans and the like (though this is an insurance issue).
Mind you you can still run home assistant on top for the gui and other integrations.
Not being the most tech savvy and being tech illiterate are two completely different things. If you are tech savvy enough to use complex features of a graphic user interface, GUI, even if they are a bit weird to set up, I recommend something like a hubitat hub. I would not recommend home assistant for you as you are not the most tech savvy person. If you are pretty much tech illiterate, you're probably just gonna have to use timers. The automation solutions for tech illiterate people don't allow for much automation flexibility. If you're somewhere in the middle and have Apple products, you can actually make very powerful HomeKit automations that run completely locally. They are pretty easy to set up as long as you don't need to use the convert to shortcut action.