the better you define your 'environment' the better.
assuming a simple hydroponic garden in a warehouse, you have a significant stability of environmental conditions.
in a tunnel greenhouse, less control, but by your choice. double or triple wall, geothermal heating/cooling, etc
But, you assume a simple IBC tank of 250 gallons (1,000 liters) for your main storage tank
and 4 others cut in half for 4 growing beds.
A swimming pool pump for circulation
A few peristaltic pumps for adding various nutrients ????
You can put in your growing tanks with a skimmer on top, like a swimming pool. That is your level control for the growing beds
You circulate water so you have control of the temperature at many points, but only need to know one for the storage tank and all the rest will be close.
light sensors, no problem.
a trio of water level switches. high : stop filling, low : start filling, and medium for S&G, you need 3 inputs.
[ S&G is a technical term often used in engineering for adding extra things that would be helpful, not not absolutely required. Slang of S&G = American for laughing so hard it comes out the other end, spoken as s#!ts and Giggles. I do not know the translation into British English]
light level in each of 4 tanks, = 4 inputs
lights off and on, 4 outputs
water temperature for control = 1
water heater for control = 1
tank water level = 3
fill pump/valve = 1
temperature = 1 per tank = 4
light sensor = 4
light controller = 4
figure 18 inputs and outputs to get started. easily done by any of the available micro-controllers we discuss on this forum.
even an ESP8266 with some expansion cards.
What you didn't ask was to put that information on your local web/network/datalog
You will need to use either a wired in network card or some WiFi device.
Also simple and common. The new NANO-33 IoT boards or an ESP32, or the ESP8266 with some expansion cards.
It is always helpful, nay, REQUIRED to Define the project before selection of parts. The answer to your 30,000 foot overview question is YES, the Arduino is a good platform and YES, there are a variety of low cost sensors that can be obtained and YES, this forum can help you each step along the way. and YES, there have lots of people that have done this before.
The answer to your focused, part number question is based on your detailing the thing you need to do.