Orlah: The status of fruit tree saplings set on synthetic grass
Question
1) A private individual brought fruit tree saplings from the nursery and left them for a period of time on synthetic grass before planting them in his garden. Does he need to restart the orlah count?
2) We were asked a similar question by a nursery that sells fruit trees to private customers. The owner wanted the nursery to look nice, so he covered the nursery area with synthetic grass. Can the saplings be placed on the synthetic grass?
The question is whether or not synthetic grass is considered a detaching surface (if so, when placing saplings on it, one must recount the orlah years).
Answer
To include nursery years in the orlah count, the trees need to be in sacks or containers with a 2.5 cm diameter hole in the bottom and be placed on the ground or a non-detaching surface (such as porous surfaces) while their roots are exposed to the ground at all times. Therefore, halachic supervision of the nursery is necessary to ensure that the saplings remain on the ground from the beginning of their production. If the sapling is moved and placed on a detaching surface (plastic sheets, etc.), the orlah count is interrupted, and a new count begins from the time of the most recent placement on the ground.
Synthetic grass has two main components: the base comprises (1) a mesh including various plastic materials, and (2) the grass fibers, also made of plastic materials. High-quality synthetic grass has high fiber density. The base is a three-layered mesh woven from plastic materials such as Palrig and latex. Perforations with a 0.5 cm diameter are made in this mesh to prevent waterlogging in the event of heavy rain and to facilitate water absorption into the soil. Throughout the mesh, there are rows of stitching for attaching the synthetic grass. Water also seeps through these stitching rows (see picture). This mesh is similar to Palrig sheets, which are also porous[1] and allow water to seep through them.
[1] Indeed, there are various types of Palrig sheets. Some have a waterproof plastic lining added to them; however, for the most part they are not completely waterproof.