The decking between my property and my neighbours is divided by a very large concrete planter box. It is very roughly 4x1x1 metres (13x3x3 feet) internally. Over the top of the planter, down the middle is a wooden fence dividing our properties. So each of our gardens shares the same soil.
Due to waterproofing issues, the existing soil is currently being removed to repair the concrete, giving me an opportunity to improve the set up.
A knowledgeable friend has warned me that sharing the soil in the planter with the neighbours is a recipe for trouble - if we have different plants with different needs for water, fertiliser, etc., it will be difficult to maintain. There may also be difficulties preventing weeds and enthusiastic plantings from taking over the other side's garden.
She recommends I put some sort of divider between the two halves so we can maintain our own soils separately.
My question is in two parts:
- Is this good advice?
- What sort of product (thin plastic lining? thicker plastic? wooden sheets? weed mats?) should I be looking for to put in the planter box before it is filled with new soil?
I tried asking at nursery, but the assistant looked confused about the request and had no suggestions.