When you go towards Shahaniya from Ryyan it is at your righthand side. When you climb the flyover that is after you pass the Sheik Faisal Museum take immediate right and come back 500 meters on the service road (Parallel to the main road) it is next to Shahaniya Sports Club. You will find a small board Arab Qatari Agriculture company something like that. The timings are 7.00-12.30 & 2.00-4.00. I'm not so sure about the afternoon timings. They also sell some fresh vegitables that they produce in the farm. You will find variety of plants there. They are also cheap compared to the ones that you get here in Doha. I went there a couple of months back. hummmm... need to go again..