Use a NodeMCU (ESP8266 based) because it have WiFi included. It can work as a light web server. You can serve HTML, but not large files (like many .js).
Instead of HTML you can use websockets to get only data from NodeMCU and all the other files (html, js, images) from another bigger server. Websockets is fast, but you still have to deal with .html, .css, .js and other files in your webserver.
If you want something even easier and lighter, take a look at MQTT, which was developed with IoT in mind.
There is lot of MQTT client for Android/Iphone/PC/Mac. You use your client to send data and commands to your NodeMCU. No need to program anything here; you simply construct a visual interface by adding controls (buttons, meters) to a blank slate. No brains job.
You will need a broker, a server that acts as a relay, receiving commands/data from your Android and resending it to your NodeMCU. And your NodeMCU can publish temp, humidity, light levels and other data to your broker. You can use multiple client at once. There is no limit.
Your broker can be an public Internet broker (many) or a private one in your LAN. There is many brokers available for different platforms. You can run one in your smartphone or any old PC. Mosquitto is a free one.
Depending on your configuration, you will be even able to access your green house from Internet and look at your girls from far away.