Everhard 1m EasyDRAIN Polymer Grate And Channel

If the grate was large enough to fit over the channel, perhaps you could have a tradesperson cut a thin slot between the channel and concrete to accept the lip

Recycled plastic or concrete channel stormwater drainage Slot drain attachments Grates include stainless steel, cast iron and plastic

slot callout into the trench and that the grates are attached to the channel prior to installation At the lower end of the drain the channel can be connected to the

slot gampang maxwin cuan jp The only reason that you would put a drain under the garden bed is because water is not draining away I recommend using Vinidex 100mm x 20m Socked Slotted